Direct Cause-effect Relationship Research Articles

Assessing teratogenic risks of gadolinium in freshwater environments: Implications for environmental health

Gadolinium (Gd) is among the rare earth elements extensively utilized in both industrial and medical applications. The latter application appears to contribute to the rise in Gd levels in aquatic ecosystems, as it is excreted via urine from patients undergoing MRI scans and often not captured by wastewater treatment systems. The potential environmental and biological hazards posed by gadolinium exposure are still under investigation. This study aimed to assess the teratogenic risk posed by a gadolinium chelate on the freshwater cnidarian Hydra vulgaris. The experimental design evaluated the impact of pure Gadodiamide (25 μg/l, 50 μg/l, 100 μg/l, 500 μg/l) and its commercial counterpart compound (Omniscan®; 100 μg/l, 500 μg/l, 782.7 mg/l) at varying concentrations using the Teratogenic Risk Index (TRI). Here we showed a moderate risk (Class III of TRI) following exposure to both tested formulations at concentrations ≥ 100 μg/l. Given the potential for similar concentrations in aquatic environments, particularly near wastewater discharge points, a teratogenic risk assessment using the Hydra regeneration assay was conducted on environmental samples collected from three rivers (Tiber, Almone, and Sacco) in Central Italy. Additionally, chemical analysis of field samples was performed using ICP-MS. Analysis of freshwater samples revealed low Gd concentrations (≤ 0.1 μg/l), despite localized increases near domestic and/or industrial wastewater discharge sites. Although teratogenic risk in environmental samples ranged from high (Class IV of TRI) to negligible (Class I of TRI), the low Gd concentrations, particularly when compared to higher levels of other contaminants like arsenic and heavy metals, preclude establishing a direct cause-effect relationship between Gd and observed teratogenic risks in environmental samples. Nevertheless, the teratogenic risks observed in laboratory tests warrant further investigation.

Association between cytomegalovirus infection and neurological disorders: A systematic review.

Cytomegalovirus (CMV) belongs to the Herpesviridae family and is also known as human herpesvirus type 5. It is a common virus that usually doesn't cause any symptoms in healthy individuals. However, once infected, the virus remains in the host's body for life and can reactivate when the host's immune system weakens. This virus has been linked to several neurological disorders, including Alzheimer's disease, Parkinson's disease, Autism spectrum disorder, Huntington's disease (HD), ataxia, Bell's palsy (BP), and brain tumours, which can cause a wide range of symptoms and challenges for those affected. CMV may influence inflammation, contribute to brain tissue damage, and elevate the risk of moderate-to-severe dementia. Multiple studies suggest a potential association between CMV and ataxia in various conditions, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, acute cerebellitis, etc. On the other hand, the evidence regarding CMV involvement in BP is conflicting, and also early indications of a link between CMV and HD were challenged by subsequent research disproving CMV's presence. This systematic review aims to comprehensively investigate any link between the pathogenesis of CMV and its potential role in neurological disorders and follows the preferred reporting items for systematic review and meta-analysis checklist. Despite significant research into the potential links between CMV infection and various neurological disorders, the direct cause-effect relationship is not fully understood and several gaps in knowledge persist. Therefore, continued research is necessary to gain a better understanding of the role of CMV in neurological disorders and potential treatment avenues.

The association between adipokines and pulmonary diseases: a mendelian randomization study

BackgroundThe role of adipokines in the development of lung diseases is significant, yet their specific relationship with different lung diseases remains unclear.MethodsIn our research, we analyzed genetic variations associated with adipokines and various lung conditions such as interstitial lung disease, chronic obstructive pulmonary disease, asthma, lung cancer, sleep apnea, pneumonia, and tuberculosis, using data from public genome-wide studies. We employed Mendelian randomization techniques, including inverse variance weighting, weighted median, and MR-Egger regression methods, and conducted sensitivity checks to validate our findings.ResultsA study using the FinnGen database, which included 198,955 participants, identified 13 SNPs associated with adiponectin. Notably, adiponectin was found to significantly reduce the risk of interstitial lung disease and idiopathic pulmonary fibrosis. However, little evidence was found to establish a direct cause-effect relationship between the six adipokines and several other lung conditions, including sarcoidosis, asthma, chronic obstructive pulmonary disease, lung cancer, tuberculosis, pneumonia, and sleep apnea syndrome.ConclusionThis study reveals a reverse link between adiponectin levels and the likelihood of interstitial lung disease, including idiopathic pulmonary fibrosis.

Eosinophilic esophagitis as a side-effect of allergen immunotherapy: protocol for a systematic review and meta-analysis.

Background. Sensitization to food and airborne allergens is common in the majority of patients with eosinophilic esophagitis (EoE). Although there is not a direct cause-effect relationship of IgE-mediated allergy with the pathogenesis of EoE, there is a growing evidence that oral desensitization to food and sublingual immunotherapy (SLIT) may induce the development of EoE as an adverse effect. As part of the 'EoE and Allergen Immunotherapy (AIT)' Task Force funded by the European Academy of Allergy and Clinical Immunology (EAACI), a systematic approach will be followed to review the evidence from the published scientific literature on the development of EoE in children and adults under any type of AIT. Methods. This systematic review will be carried out following the PRISMA statement guidelines. Studies will be assessed for inclusion in the review according to the Population-Interventions-Comparators-Outcomes (PICO) criteria. Results. Expected outcomes will provide evidence on the AIT-EoE development connection. Conclusions. The findings from this review will be used as a reference to provide useful guidelines for physicians treating patients with EoE and/or are practicing AIT.

Effect of operative time in outcomes following surgical fixation of hip fractures: a multivariable regression analysis of 35,710 patients.

Prolonged operative time is a risk factor for increased morbidity and mortality after open reduction and internal fixation (ORIF) of hip fractures. However, the quantitative nature of such association, including graduated risk levels, has yet to be described. This study outlines the graduated associations between operative time and (1) healthcare utilisation, and (2) 30-day complications after ORIF of hip fractures. The National Surgical Quality Improvement Program (NSQIP) database was queried (January 2016-December 2019) for all patients who underwent ORIF of hip fractures (n = 35,710). Demographics, operative time, fracture type, and comorbidities were recorded. Outcomes included healthcare utilisation (e.g., prolonged length of stay [LOS>2 days], discharge disposition, 30-day readmission, and reoperation), inability to weight-bear (ITWB) on postoperative day-1 (POD-1), and any 30-day complication. Adjusted multivariate regression models evaluated associations between operative time and measured outcomes. Operative time <40 minutes was associated with lower odds of prolonged LOS (odds ratio [OR] 0.77), non-home discharge (OR 0.85), 30-day readmission (OR 0.85), and reoperation (OR 0.72). Operative time ⩾80 minutes was associated with higher odds of ITWB on POD-1 (OR 1.17). Operative time ⩾200 minutes was associated with higher odds of deep infection (OR 7.5) and wound complications (OR 3.2). The odds of blood transfusions were higher in cases ⩾60 minutes (OR1.3) and 5-fold in cases ⩾200 minutes (OR 5.4). The odds of venous thromboembolic complications were highest in the ⩾200-minute operative time category (OR 2.5). Operative time was not associated with mechanical ventilation, pneumonia, delirium, sepsis, urinary tract infection, or 30-day mortality. Increasing operative time is associated with a progressive increase in the odds of adverse outcomes following hip fracture ORIF. While a direct cause-effect relationship cannot be established, an operative time of <60 minutes could be protective. Perioperative interventions that shorten operative time without compromising fracture reduction or fixation should be considered.

Role of air pollution on COVID-19 in Istanbul

There are many types of research on strong relations between air pollution and the respiration system. This paper is related to the effect of air pollution on pandemic case numbers. By analyses of the number of patients and mean air pollution (µg/m³) data by using data mining, it is concluded that there was evidence of this relationship with a significant level alpha = 0,10. This paper estimates "the number of patients with coronavirus" as a function of daily air pollution and corona case numbers data using single ANN, LSTM, and W-ANN, W-LSTM hybrid methods. This paper explains small, meso, and large scale factors and their role on COVID-19 patients. This finding does not demonstrate a direct cause-effect relationship between air pollution and COVID-19 patients. This study shows the importance of pollution on the number of patients with COVID -19 infection. Although our results have significant uncertainties, we can clearly distinguish the contribution of air pollution to COVID-19 patients. When we used wavelet transformation of air pollution data to estimate COVID-19 patient’s numbers, R2 score is increased in both ANN and LSTM between [0.01- 0.10]. Nevertheless, the actual number of patients is influenced by many additional factors such as the country's health system. After error analysis, sMAPE [3.6-5.9] changed, there is sufficient evidence of model results (M3, M4 Hybrid LSTM) and observation. (0.91

High prevalence of latent tuberculosis using the QuantiFERON-TB Gold Plus test in Takayasu arteritis.

This study aims to investigate latent tuberculosis using the QuantiFERON-TB Gold Plus method in patients with Takayasu arteritis (TA). This case-control study included 22 patients with TA (3 males, 19 females; median age: 36.5 years; IQR, 32 to 50 years), 22 healthy individuals (3 males, 19 females; median age: 38.5 years; IQR, 32.5 to 50 years), and 66 patients with diffuse connective tissue diseases (DCTDs) (4 males, 62 females; median age: 41 years; IQR, 29.8 to 54 years). Two control groups were formed: (i) age- and sex-matched healthy individuals and (ii) patients with other DCTDs. Epidemiological data were collected, and the QFT-Plus test was performed. The QFT-plus positivity was compared among the groups. A higher prevalence of QFT-Plus positive cases was observed in the TA group (8/22) than in the healthy control group (1/22) (p=0.020) or in the group with other DCTDs (3/66) (p=0.001). There was a statistically significant difference in the past pulmonary tuberculosis prevalence between the TA and DCTD groups (p=0.013). The prevalence of latent tuberculosis in TA patients (36.4%) was higher than that in both control groups and higher than the prevalence of latent tuberculosis among the general Brazilian population. Although a positive association was found, it is not possible to establish a direct cause-effect relationship. Given the increasing use of anti-cytokine therapies in TA, it is necessary to thoroughly screen patients with TA before initiating immunosuppressive therapy to avoid tuberculosis reactivation.

Characterization of agroforestry systems and their effectiveness in soil fertility enhancement in the south-west region of Cameroon

Crop productivity depends almost entirely on the fertility of the soil. This in turn influences food security at the household level. Thus, for crop productivity to be high and ensure food security, the level of soil fertility needs to increase. However, poor agricultural practices and other phenomena such as soil erosion have led to soil infertility across Cameroon. This necessitates that more sustainable agricultural practices should be identified and vulgarized. In this light, this study was initiated to evaluate the role of different agroforestry systems (a sustainable agricultural practice), in enhancing soil fertility in order to propose an appropriate practice to farmers as a sustainable option for soil fertility improvement. The study was carried out in Mbelenka, south west region of Cameroon. Data was collected through household surveys, key informant interviews, focus group discussions, and direct field observations. Findings revealed that, three main agroforestry systems (agrosilvopastoral, silvopastoral, and agrisilvicultural systems) were dominant characterized by several practices, components, and functions. Most farmers (52%) perceived the soils to be less fertile, and the agrosilvopastoral system was perceived by most farmers (57%) to be characterized by the highest level of soil fertility. Most farmers (53%) equally perceived that, the agrosilvopastoral system was the most effective in enhancing soil fertility. Correlation and regression analysis showed the existence of a statistically significant (p < 0.01) direct non-cause effect and a direct cause-effect relationship between soil fertility and the practice of agrosilvopastoral and agrisilvicultural agroforestry systems. This implies that, the practice of these two systems contributes towards improving soil fertility. Based on these findings, it is recommended that, farmers should practice agroforestry systems especially the agrosilvopastoral and agrisilvicultural systems, for they have huge potentials to enhance soil fertility, thereby improving crop productivity and food security.

Sar1b mutant mice recapitulate gastrointestinal abnormalities associated with chylomicron retention disease

Chylomicron retention disease (CRD) is an autosomal recessive disorder associated with biallelic Sar1b mutations leading to defects in intracellular chylomicron (CM) trafficking and secretion. To date, a direct cause-effect relationship between CRD and Sar1b mutation has not been established, but genetically modified animal models provide an opportunity to elucidate unrecognized aspects of these mutations. To examine the physiological role and molecular mechanisms of Sar1b function, we generated mice expressing either a targeted deletion or mutation of human Sar1b using the CRISPR-Cas9 system. We found that deletion or mutation of Sar1b in mice resulted in late-gestation lethality of homozygous embryos. Moreover, compared with WT mice, heterozygotes carrying a single disrupted Sar1b allele displayed lower plasma levels of triglycerides, total cholesterol, and HDL-cholesterol, along with reduced CM secretion following gastric lipid gavage. Similarly, decreased expression of apolipoprotein B and microsomal triglyceride transfer protein was observed in correlation with the accumulation of mucosal lipids. Inefficient fat absorption in heterozygotes was confirmed via an increase in fecal lipid excretion. Furthermore, genetically modified Sar1b affected intestinal lipid homeostasis as demonstrated by enhanced fatty acid β-oxidation and diminished lipogenesis through the modulation of transcription factors. This is the first reported mammalian animal model with human Sar1b genetic defects, which reproduces some of the characteristic CRD features and provides a direct cause-effect demonstration.

Observation of a 27 Days Periodicity in Melanoma Diagnosis

Streams from the dark universe may affect biologic processes on Earth including occurrence of cancer. Here, we have recovered complete daily melanoma incidence rates 1982–2014 in Australia. If there is no other external cause for melanoma, its seasonal rate should be steady with a broad maximum during local summertime due to increased solar UV exposure. The reported melanoma cases show instead: (A) a modulation repeating every [Formula: see text] weeks; (B) a time-dependence which relates also with Moon’s geocentric orbital position, while it does not fit concurrently measured solar activity; and (C) a modulation periodicity strikingly coinciding with the Moon’s sidereal periodicity of 27.3 days, which is fixed to remote stars and not to the Sun. These findings show that the associated cause must be of exo-solar origin, and not only due steady solar UV exposure. A possible interpretation of the finding is the underlying working hypothesis itself, namely the flux of slow speed streaming DM is temporally enhanced due to gravitational (self-)focusing by the solar system. Interestingly, the gravitational focusing effect by the Moon itself towards the Earth covers speeds up to [Formula: see text][Formula: see text]km/s, fitting within the widely assumed velocity distribution of DM constituents at [Formula: see text][Formula: see text]km/s. The derived observations for melanoma diagnosis are a novel model-independent finding with potential public health implications and possible relevance for other diseases. The results of this work also serve as accumulating and independent signatures strengthening previous physics claims being at work at the Sun and Earth’s upper atmosphere, inspiring a novel cross-disciplinary approach for the dark matter (DM) paradigm. In future, the 27.3 days periodicity does not necessarily require long-term physical and medical measurements to search for a direct cause-effect relationship. Potential candidates from the dark sector are the highly ionizing anti-quark nuggets, magnetic monopoles, but also particles like dark photons; other as yet unpredicted DM constituents with sufficient impact on the highly sensitive living matter could be at work.

Environmental enrichment alleviates the deleterious effects of stress in experimental autoimmune encephalomyelitis.

BackgroundClinical observations support the hypothesis that stressful events increase relapse occurrence in multiple sclerosis patients, while stress-reduction strategies can modulate this effect. However, a direct cause-effect relationship between stress level and relapse cannot be firmly established from these data.ObjectivesThe purpose of this work was to address whether modulation of stress could interfere with symptom relapse in an animal model of multiple sclerosis with relapsing-remitting course.MethodsMice bred in standard or enriched environment were subjected to repeated acute stress during the remission phase of relapsing-remitting PLP-induced experimental autoimmune encephalomyelitis.ResultsWe report that repeated acute stress induced a twofold increase in relapse incidence in experimental autoimmune encephalomyelitis. On the other hand, environmental enrichment reduced relapse incidence and severity, and reversed the effects of repeated acute stress.ConclusionThese data provide the platform for further studies on the biological processes that link stress and multiple sclerosis relapses in a suitable animal model.

The Problem of Gender Verification in Sport: Legal, Medical and Ethical Aspects

Equal opportunities for women to participate in sports, including women originally considered male, are accompanied with a debate on the need for gender verification for fear of participation in women’s competitions of female athletes with genetic characteristics more typical of men, which, in some experts’ opinions, gives them unfounded starting advantages. Thus, it is necessary to consider legal, medical and ethical aspects of gender verification in high performance sports. The article analyzes the main alterations developed by the International Association of Athletics Federations (IAAF) Rules for selection of sportswomen with violations of gender formation for participation in competitions. Given the position of the Special Rapporteur of the UN Human Rights Council, the author considers the issue concerning the compliance of these changes with international principles and norms in the field of human rights protection with due regard to non — discrimination, respect for honor, dignity and integrity of the person. It is concluded that there is considerable uncertainty about admissibility of the use of testosterone level as a universal criterion for gender verification, as well as the availability of direct cause-effect relationship between the corresponding hormonal characteristics and the sports results achieved. The author draws attention to the ethical element of gender verification in sport related to the methods offered by IAAF to assess the sufficient level of femininity and the requirement of its adjustment to artificially determined indicators, even when the principle of confidentiality is declared.

Hospitalization Rates for Respiratory Diseases After L'Aquila Earthquake.

The study aims to investigate the impact of the earthquake on public health, in terms of hospitalizations for respiratory diseases in the Abruzzo region, focusing on the area damaged by the earthquake “Crater”. We collected data of hospitalizations of residents in Abruzzo between 2009 and 2015. Hospital Discharge Records (HDRs) with a primary diagnosis of respiratory disease were included and divided into pneumonia, Chronic Obstructive Pulmonary Disease (COPD), and respiratory insufficiency. Absolute frequencies and standardized hospitalization rates were calculated to perform both a short-term and a medium-long term analysis. A linear regression was performed using standardized hospitalization rates and the time. A total of 108.669 respiratory-related records were collected and the most frequent subgroup was respiratory insufficiency. Standardized Hospitalization Rates (SHRs) for respiratory diseases resulted higher in the non-Crater than Crater area, but the short-term analysis showed a significant increase in hospitalizations for pneumonia and respiratory insufficiency in the Crater area. The medium-long term analysis reported a significant difference on the slope decrease of hospitalizations for acute and chronic respiratory diseases in the Crater versus the non-Crater area. The earthquake may have played a triggering role in the increased detection of respiratory diseases. A temporal relationship between the quake and an increase in admissions was found although it is not yet possible to detect a direct cause-effect relationship.

A cross-sectional study of the relationship between infant Thimerosal-containing hepatitis B vaccine exposure and attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is characterized by a marked pattern of inattention and/or hyperactivity-impulsivity that is inconsistent with developmental level and interferes with normal functioning in at least two settings. This study evaluated the hypothesis that infant Thimerosal-containing hepatitis B vaccine (T-HepB) exposure would increase the risk of an ADHD diagnosis. This cross-sectional study examined 4393 persons between 13 and 19 years of age from the combined 1999–2004 National Health and Nutritional Examination Survey (NHANES) by analyzing demographic, immunization, socioeconomic, and health-related variables using the SAS system. Three doses of T-HepB exposure in comparison to no exposure significantly increased the risk of an ADHD diagnosis using logistic regression (adjusted odds ratio=1.980), linear regression (adjusted beta-coefficient=0.04747), Spearman’s rank (Rho=0.04807), and 2×2 contingency table (rate ratio=1.8353) statistical modeling even when considering other covariates such as gender, race, and socioeconomic status. Current health status outcomes selected on an a priori basis to not be biologically plausibly linked to T-HepB exposure showed no relationship with T-HepB. The observed study results are biologically plausible and supported by numerous previous epidemiological studies, but because the NHANES data is collected on a cross-sectional basis, it is not possible to ascribe a direct cause-effect relationship between exposure to T-HepB and an ADHD diagnosis. During the decade from 1991 to 2001 that infants were routinely exposed to T-HepB in the United States (US), an estimated 1.3-2.5 million children were diagnosed with ADHD with excess lifetime costs estimated at US $350-$660 billion as a consequence of T-HepB. Although Thimerosal use in the HepB in the US has been discontinued, Thimerosal remains in the HepB in developing countries. Routine vaccination is an important public health tool to prevent infectious diseases, but every effort should be made to eliminate Thimerosal exposure.

Blood Lead Levels and Learning Disabilities: A Cross-Sectional Study of the 2003-2004 National Health and Nutrition Examination Survey (NHANES).

Difficulties in the acquisition and use of listening, speaking, reading, writing, reasoning or mathematical abilities are present among persons diagnosed with learning disabilities (LDs). Previous studies suggest a significant relationship between lead (Pb) exposure and LDs. This study evaluated the potential dose-response relationship between blood Pb levels and the risk of LDs. This cross-sectional study examined 1411 children (32,788,743 weighted-persons) between 6 and 15 years old from the 2003–2004 National Health and Nutrition Examination Survey (NHANES) by analyzing demographics, health related-questions, and laboratory tests using survey logistic and frequency modeling in SAS. On a µg Pb/dL basis, a significant dose-dependent relationship between increasing blood Pb levels and increasing risk of LDs was observed (odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.03–1.43). The relationship remained significant when examining covariates such as gender and race (OR = 1.19, 95% CI = 1.00–1.40). By contrast, no dose-dependence was observed between increasing blood Pb levels and the risk of hay fever in the last year (OR = 0.77, 95% CI = 0.56–1.056), a non-plausibly biologically related outcome of blood Pb levels. Persons in the 50th–75th (12.80%) and 75th–100th (17.14%) percentiles of blood Pb were significantly more likely to have LDs than persons in the 0–50th percentile of blood Pb (8.78%). An estimated 1 million persons born in the US from 1989 to 1998 developed LDs from elevated blood Pb levels. Overall, this study revealed a significant dose-dependent association between increasing childhood blood Pb levels and the risk of a LD diagnosis, but it was not possible to ascribe a direct cause-effect relationship between blood Pb exposure and LD diagnosis. Childhood Pb exposure should be considered when evaluating children with LDs, and continuing efforts should be made to reduce Pb exposure.

Detection of Cyprinid Herpesvirus 1 DNA in cutaneous squamous cell carcinoma of koi carp (Cyprinus carpio).

Cutaneous squamous cell carcinoma (cSCC) is an uncommon disease affecting koi carp (Cyprinus carpio). Cutaneous papilloma (carp pox) is a benign epidermal proliferation reported in koi and has been shown to be caused by Cyprinid Herpesvirus 1 (CyHV1). Histological, ultrastructural and molecular investigations were carried out aiming to investigate the aetiology of cSCC within archived tissue samples. Surgical samples of masses located on the integument, fins and lips of 13 koi carp belonging to different private owners were included in this retrospective study. CyHV1 DNA and RNA presence were investigated in five cSCC formalin-fixed paraffin-embedded tissue samples to recognize CyHV1 presence and its replication activity. All cases were histologically diagnosed as cSCC. The ultrastructural observations confirmed the squamous differentiation of neoplastic epithelial cells, which showed abundant tonofilament bundles and desmosomes. Although no virus particles were revealed ultrastructurally, the molecular investigation detected viral DNA in five epidemiologically unrelated cSCC. Viral transcript analysis revealed no evidence for viral replication in the tested cSCC, which could be consistent with latent infection. These findings illustrate the frequent association of carp cSCC with CyHV1, although a direct cause-effect relationship cannot be established at this time. Therefore, surveillance programmes should take into account the suspected viral origin of cSCC to better inform prevention and control of CyHV1 in the future.

Exacerbated in vivo metabolic changes suggestive of a spontaneous muscular vaso-occlusive crisis in exercising muscle of a sickle cell mouse

While sickle cell disease (SCD) is characterized by frequent vaso-occlusive crisis (VOC), no direct observation of such an event in skeletal muscle has been performed in vivo. The present study reported exacerbated in vivo metabolic changes suggestive of a spontaneous muscular VOC in exercising muscle of a sickle cell mouse. Using magnetic resonance spectroscopy of phosphorus 31, phosphocreatine and inorganic phosphate concentrations and intramuscular pH were measured throughout two standardized protocols of rest – exercise – recovery at two different intensities in ten SCD mice. Among these mice, one single mouse presented divergent responses. A statistical analysis (based on confidence intervals) revealed that this single mouse presented slower phosphocreatine resynthesis and inorganic phosphate disappearance during the post-stimulation recovery of one of the protocols, what could suggest an ischemia. This study described, for the first time in a sickle cell mouse in vivo, exacerbated metabolic changes triggered by an exercise session that would be suggestive of a live observation of a muscular VOC. However, no evidence of a direct cause-effect relationship between exercise and VOC has been put forth.

Osteocalcin and glucose metabolism: assessment of human studies

Osteocalcin, a protein secreted by osteoblasts, is recognized as a biomarker of bone mineralization. Besides, animal experimental studies have shown that osteocalcin could play an important role in glucose metabolism. Over the course of the last decade, this theory has been investigated in several human studies. Most of the results obtained from these reports support a positive correlation between total and undercarboxylated osteocalcin and insulin secretion/sensitivity. Studies also corroborate a reverse association with glycemic parameters such as fasting glucose and glycated hemoglobin. Nevertheless, because most of the studies published are observational, it is not possible to yet confirm a direct cause-effect relationship. Research in the field will surely contribute to the development of new pharmacological strategies for the treatment of endocrine diseases.

Vitamina D – Perspetivas Atuais

A vitamina D tem como efeito biológico principal a promoção da mineralização óssea e a regulação da homeostasia do metabolismo cálcio-fósforo. A sua função biológica extra-esqueleto tem sido amplamente estudada e o seu défice associado a risco aumentado para diversas patologias, nomeadamente autoimunes, neoplásicas, cardiovasculares e neurológicas, entre outras. No entanto, esta mantém-se uma área de controvérsia e ficam por demonstrar a relação causa-efeito entre deficiência de vitamina D e patologia não esquelética, e o benefício da suplementação com este objetivo. Nos indivíduos em risco de hipovitaminose a suplementação é segura, barata e com benefício demonstrado na prevenção de fraturas e quedas. É feita uma abordagem da síntese, metabolismo e modo de ação da vitamina D. Faz-se uma revisão sumária da fisiopatologia da vitamina D na pele - a influência da pigmentação cutânea e do uso de fotoproteção na sua síntese, e a sua relação com as dermatoses mais frequentes.

Effect of Small-Scale Turbulence on the Physiology and Morphology of Two Bloom-Forming Cyanobacteria.

The main goal of the present work is to test the hypothesis that small-scale turbulence affected physiological activities and the morphology of cyanobacteria in high turbulence environments. Using quantified turbulence in a stirring device, we conducted one set of experiments on cultures of two strains of cyanobacteria with different phenotypes; i.e., unicellular Microcystis flos-aquae and colonial Anabaena flos-aquae. The effect of small-scale turbulence examined varied from 0 to 8.01×10−2 m2s-3, covering the range of turbulence intensities experienced by cyanobacteria in the field. The results of photosynthesis activity and the cellular chlorophyll a in both strains did not change significantly among the turbulence levels, indicating that the potential indirect effects of a light regime under the gradient of turbulent mixing could be ignored. However, the experiments demonstrated that small-scale turbulence significantly modulated algal nutrient uptake and growth in comparison to the stagnant control. Cellular N and C of the two stains showed approximately the same responses, resulting in a similar pattern of C/N ratios. Moreover, the change in the phosphate uptake rate was similar to that of growth in two strains, which implied that growth characteristic responses to turbulence may be dependent on the P strategy, which was correlated with accumulation of polyphosphate. Additionally, our results also showed the filament length of A. flos-aquae decreased in response to high turbulence, which could favor enhancement of the nutrient uptake. These findings suggested that both M. flos-aquae and A. flos-aquae adjust their growth rates in response to turbulence levels in the ways of asynchronous cellular stoichiometry of C, N, and P, especially the phosphorus strategy, to improve the nutrient application efficiency. The fact that adaptation strategies of cyanobacteria diversely to turbulence depending on their physiological conditions presents a good example to understand the direct cause—effect relationship between hydrodynamic forces and algae.