-
Life (Basel, Switzerland) Mar 2024Homochirality is an obvious feature of life on Earth. On the other hand, extraterrestrial samples contain largely racemic compounds. The same is true for any common... (Review)
Review
Homochirality is an obvious feature of life on Earth. On the other hand, extraterrestrial samples contain largely racemic compounds. The same is true for any common organic synthesis. Therefore, it has been a perplexing puzzle for decades how these racemates could have formed enantiomerically enriched fractions as a basis for the origin of homochiral life forms. Numerous hypotheses have been put forward as to how preferentially homochiral molecules could have formed and accumulated on Earth. In this article, it is shown that homochirality of the abiotic organic pool at the time of formation of the first self-replicating molecules is not necessary and not even probable. It is proposed to abandon the notion of a molecular ensemble and to focus on the level of individual molecules. Although the formation of the first self-replicating, most likely homochiral molecule, is a seemingly improbable event, on a closer look, it is almost inevitable that some homochiral molecules have formed simply on a statistical basis. In this case, the non-selective leap to homochirality would be one of the first steps in chemical evolution directly out of a racemic "ocean". Moreover, most studies focus on the chirality of the primordial monomers with respect to an asymmetric carbon atom. However, any polymer with a minimal size that allows folding to a secondary structure would spontaneously lead to asymmetric higher structures (conformations). Most of the functions of these polymers would be influenced by this inherently asymmetric folding. Furthermore, a concept of physical compartmentalization based on rock nanopores in analogy to nanocavities of digital immunoassays is introduced to suggest that complex cell walls or membranes were also not required for the first steps of chemical evolution. To summarize, simple and universal mechanisms may have led to homochiral self-replicating systems in the context of chemical evolution. A homochiral monomer pool is deemed unnecessary and probably never existed on primordial Earth.
PubMed: 38541666
DOI: 10.3390/life14030341 -
International Journal of Molecular... Jun 2023Acromegaly is a rare disease with several systemic complications that may lead to increased overall morbidity and mortality. Despite several available treatments,... (Review)
Review
Acromegaly is a rare disease with several systemic complications that may lead to increased overall morbidity and mortality. Despite several available treatments, ranging from transsphenoidal resection of GH-producing adenomas to different medical therapies, complete hormonal control is not achieved in some cases. Some decades ago, estrogens were first used to treat acromegaly, resulting in a significant decrease in IGF1 levels. However, due to the consequent side effects of the high dose utilized, this treatment was later abandoned. The evidence that estrogens are able to blunt GH activity also derives from the evidence that women with GH deficiency taking oral estro-progestins pills need higher doses of GH replacement therapy. In recent years, the role of estrogens and Selective Estrogens Receptor Modulators (SERMs) in acromegaly treatment has been re-evaluated, especially considering poor control of the disease under first- and second-line medical treatment. In this review, we analyze the state of the art concerning the impact of estrogen and SERMs on the GH/IGF1 axis, focusing on molecular pathways and the possible implications for acromegaly treatment.
Topics: Humans; Female; Acromegaly; Selective Estrogen Receptor Modulators; Receptors, Estrogen; Estrogens; Adenoma; Insulin-Like Growth Factor I; Human Growth Hormone
PubMed: 37373068
DOI: 10.3390/ijms24129920 -
JACC. Clinical Electrophysiology Feb 2018
Topics: Cardiovascular Infections; Cohort Studies; Defibrillators, Implantable; Humans; Pacemaker, Artificial
PubMed: 29749939
DOI: 10.1016/j.jacep.2017.10.007 -
Journal of Obstetrics and Gynaecology... Apr 2016Surgical ovarian wedge resection was the first established treatment for women with anovulatory polycystic ovary syndrome (PCOS) but was largely abandoned both due to...
Surgical ovarian wedge resection was the first established treatment for women with anovulatory polycystic ovary syndrome (PCOS) but was largely abandoned both due to the risk of postsurgical adhesions and the introduction of medical ovulation induction. Laparoscopic ovarian drilling (LOD) is an alternative method to induce ovulation in PCOS patients with clomiphene citrate resistance instead of gonadotropins. Surgical therapy with LOD may avoid or reduce the need for gonadotropins or may facilitate their use. However, the procedure, though effective, can be traumatic on the ovaries, which may cause postoperative adhesions and/or diminished ovarian reserve. In over-enthusiastic hands, this day-care procedure might lead to iatrogenic premature ovarian failure in young women. Some trials have compared LOD with gonadotropins, but, because of variations in study design and small sample size, the results are inconsistent and definitive conclusions about the relative efficacy of LOD and gonadotropins cannot be extracted from the individual studies. Today, evidence-based reviews conclude that there is no evidence of a significant difference in rates of clinical pregnancy, live birth or miscarriage in women with clomiphene-resistant PCOS undergoing LOD compared to other medical treatments. The reduction in multiple pregnancy rates in women undergoing LOD is the only pro-LOD argument. However, there are ongoing serious concerns about the long-term effects of LOD on ovarian function.
PubMed: 27046958
DOI: 10.1007/s13224-015-0799-1 -
Heliyon Sep 2019Zambia is endowed with mineral wealth that includes copper, cobalt, gold, nickel, lead, silver, uranium, zinc, and numerous precious and semi-precious stones. Mining... (Review)
Review
Zambia is endowed with mineral wealth that includes copper, cobalt, gold, nickel, lead, silver, uranium, zinc, and numerous precious and semi-precious stones. Mining activities are predominantly found on the Copperbelt and North-Western Provinces, although these minerals are dotted all over the country. Copper mining in Zambia dates back to the 1900s and this period witnessed massive investment in mine development with concomitant increase in support facilities including building of new towns, roads and other commercial infrastructure. The mining sector has therefore evoked considerable national attention for its potential to contribute towards economic growth, job creation and poverty alleviation. However, mining and mineral processing by its very nature comes with environmental costs and the effects can continue long after the mining has stopped. The aim of this article was to review the relevant publications on the impacts of air pollution arising from mining operations with respect to human health, plants, animals and infrastructure and synthesize the views of researchers and suggest any additional research required to inform policy and remedial actions. This review has revealed that there is a paucity of studies on mining-related air pollution in Zambia. The main identified air pollutants were SO and particulate matter (PM), both fine and ultrafine (PM, PM, PM and PM). The main sources of these pollutants were flue gases from smelter operations and dusts within the mines and those blown from both operational and abandoned waste rock, overburden and tailings dump sites. The identified occupational diseases for miners in Zambia were silicosis and tuberculosis, which have been compounded by the prevalence of HIV/AIDS. In the hotspot townships of air-borne exposures from smelter emissions in Mufulira, ambient air SO levels exceeded the 'safe' limits of international and National standards. Moreover, the top soils have turned acidic and have become laden with heavy metals (Pb, Zn, Cu, Co and Fe). These metals were also found in the dust deposited on leaves of crops. There were also visual signs of impaired vegetation cover and corroded housing infrastructure in the affected areas. In the vicinity of the abandoned Pb-Zn mine in Kabwe, the soils have been contaminated by heavy metals and pathological lead poisoning of children and wild mammals have occurred. The review article has further examined study gaps and suggested areas that need further research in order to address the challenges arising from the legacy of copper mining in Zambia. These include comprehensive PM characterization from mining environments, extent of occupation exposure to air pollutants, efficiency and efficacy of airborne control technologies, health risks and epidemiological studies in mining towns, and the influence of exposure to PM on pulmonary tuberculosis and HIV/aids among miners.
PubMed: 31687579
DOI: 10.1016/j.heliyon.2019.e02485 -
Orthopaedics & Traumatology, Surgery &... Feb 2017Capsule/ligament lesions of the lateral compartment of the ankle lead to lateral laxity, which is a prime contributor to chronic ankle instability. Lateral ligament... (Review)
Review
Capsule/ligament lesions of the lateral compartment of the ankle lead to lateral laxity, which is a prime contributor to chronic ankle instability. Lateral ligament reconstruction stabilizes the joint. Exhaustive preoperative clinical and paraclinical work-up is essential. The present article classifies, presents and criticizes the main techniques in terms of long-term stabilization and reduction of osteoarthritis risk. Anatomic ligament repair with reinforcement (mainly extensor retinaculum) or anatomic ligament reconstruction are the two recommended options. Non-anatomic reconstructions using the peroneus brevis should be abandoned. Arthroscopy is increasingly being developed, but results need assessment on longer follow-up than presently available. Postoperative neuromuscular reprogramming is fundamental to optimal recovery. Finally, the concept of complex ankle instability is discussed from the diagnostic and therapeutic points of view. The various forms of ligament reconstruction failure and corresponding treatments are reported.
Topics: Ankle Injuries; Arthroscopy; Decision Support Techniques; Humans; Joint Instability; Lateral Ligament, Ankle; Plastic Surgery Procedures
PubMed: 27871968
DOI: 10.1016/j.otsr.2016.06.026 -
Animals : An Open Access Journal From... Feb 2024The historical relationship between humans and dogs has involved selective breeding for various purposes, such as hunting, guarding, and service roles. However, over... (Review)
Review
The historical relationship between humans and dogs has involved selective breeding for various purposes, such as hunting, guarding, and service roles. However, over time, there has been a shift in preferences from functionality to aesthetics, which has influenced the diverse sizes, shapes, and coats of dog breeds. This review looks at fashionable dog breeding and questions the ethics of prioritising looks over health and behaviour. It aims to alert potential owners, breeders, and regulators to the importance of considering a dog's overall well-being, not just its appearance, which has resulted in fad breeding, leading to genetic disorders, health issues, and a loss of biodiversity. Ethical concerns arise from breeding brachycephalic breeds with respiratory conditions, inbreeding causing inherited disorders, and overbreeding popular breeds while shelter dogs remain unadopted. Additionally, the impact of cosmetic surgeries on popular dog breeds, as well as the neglect of behavioural traits in favour of physical characteristics and strict breeding practices are also considered. The current breeding model can have a negative impact on the emotional and cognitive well-being of dogs, resulting in issues such as aggression, anxiety, and other behavioural problems that can significantly reduce their overall quality of life. Unregulated breeding practices and the demand for rare breeds can lead to illegal breeding, compromising animal welfare. Prospective owners, veterinarians, kennel clubs, and legislators all need to play a responsible role in protecting animals.
PubMed: 38473141
DOI: 10.3390/ani14050756 -
American Journal of Physiology. Renal... May 2004The evolution of the vertebrate kidney records three occasions, each separated by about 50 million years, when fish have abandoned glomeruli to produce urine by tubular... (Review)
Review
The evolution of the vertebrate kidney records three occasions, each separated by about 50 million years, when fish have abandoned glomeruli to produce urine by tubular mechanisms. The recurring dismissal of glomeruli suggests a mechanism of aglomerular urine formation intrinsic to renal tubules. Indeed, the transepithelial secretion of organic solutes and of inorganic solutes such as sulfate, phosphate, and magnesium can all drive secretory water flow in renal proximal tubules of fish. However, the secretion of NaCl via secondary active transport of Cl is the primary mover of secretory water flow in, surprisingly, proximal tubules of both glomerular and aglomerular fish. In filtering kidneys, the tubular secretion of solute and water is overshadowed by reabsorptive transport activities, but secretion progressively comes to light as glomerular filtration decreases. Thus the difference between glomerular and aglomerular urine formation is more a difference of degree than of kind. At low rates of glomerular filtration in seawater fish, NaCl-coupled water secretion serves to increase the renal excretory capacity by increasing the luminal volume into which waste, excess, and toxic solutes can be secreted. The reabsorption of NaCl and water in the distal nephron and urinary bladder concentrates unwanted solutes for excretion while minimizing renal water loss. In aglomerular fish, NaCl-coupled water secretion across proximal tubules replaces glomerular filtration to increase renal excretory capacity. A review of the literature suggests that tubular secretion of NaCl and water is an early function of the vertebrate proximal tubule that has been retained throughout evolution. Active transepithelial Cl secretion takes place in gall bladders studied as models of the mammalian proximal tubule and in proximal tubules of amphibians and apparently also of mammals. The tubular secretion of Cl is also observed in mammalian distal tubules. The evidence consistent with and for Cl secretion in, respectively, proximal and distal tubules of the mammalian kidney calls for a reexamination of basic assumptions in renal physiology that may lead to new opportunities for managing some forms of renal disease.
Topics: Adaptation, Physiological; Animals; Biological Evolution; Fishes; Kidney Glomerulus; Kidney Tubules; Water-Electrolyte Balance
PubMed: 15075177
DOI: 10.1152/ajprenal.00351.2003 -
Frontiers in Research Metrics and... 2023Patent protection typically lasts about 20 years from the filing date and is in exchange for sufficiently disclosing the invention. The disclosure aims to enrich... (Review)
Review
Patent protection typically lasts about 20 years from the filing date and is in exchange for sufficiently disclosing the invention. The disclosure aims to enrich technical knowledge globally, promote creativity and technological innovation and contribute to sustainable socio-economic development. After this protection period, the patent expires, and in principle, any person may begin practicing the specific subject matter previously protected by the patent. Since the invention originally met all the patentability requirements, it was disclosed sufficiently to stimulate further innovation by others through a thorough understanding of existing developments in the patent literature. Thus, in addition to scholarly research articles, this makes patents potentially valuable sources of technical information in research and academia, unlocking new technology opportunities. We use the exploratory research method to study a potentially genuine and vital research stream that uncovers the overlooked yet valuable scientific and technical information sources that higher education institutions could utilize to complement academic research articles. This work establishes a necessary research agenda that critically challenges researchers to tap into the immediately available and promising technology opportunities presented by patents in the public domain. Using case studies to gain in-depth, multi-faceted explorations about the impact of these patents, we find that technologies contained in expired patents, abandoned patents, and technologies not protected by IPRs, resulting in improved research quality and increased collaboration with industry, if adequately exploited and integrated with other technologies. Moreover, this could lead to increased academic patenting and commercialization with support from the university's Technology Transfer Office.
PubMed: 37008286
DOI: 10.3389/frma.2023.1115457