Alterations In Calcium Levels Research Articles

Effects of zinc in podocytes and cortical collecting duct in vitro and Dahl salt-sensitive rats in vivo

Zinc is one of the essential divalent cations in the human body and a fundamental microelement involved in the regulation of many cellular and subcellular functions. Experimental studies reported that zinc deficiency is associated with renal damage and could increase blood pressure. It was proposed that zinc dietary supplementation plays a renoprotective role. Our study aimed to investigate the effects of zinc on intracellular signaling in renal cells and explore the correlation between dietary zinc and the progression of salt-induced hypertension. The impact of extracellular zinc concentrations on two different kidney epithelial cell types - podocytes and principal cells of the cortical collecting duct (CCD), was tested. In podocytes, a rise in extracellular zinc promotes TRPC6 channel-mediated calcium entry but not altered intracellular zinc levels. However, we observe the opposite effect in CCD cells with no alteration in calcium levels and steady-state elevation in intracellular zinc. Moreover, prolonged extracellular zinc exposure leads to cytotoxic insults in CCD cells but not in podocytes, characterized by increased cell death and disrupted cytoskeletal organization. Next, we tested if dietary zinc plays a role in the development of hypertension in Dahl salt-sensitive rats. Neither zinc-rich nor deficient diets impact the regular development of salt-sensitive hypertension. These results suggest specialized roles for zinc in renal function, implicating its involvement in proliferation and apoptosis in CCD cells and calcium signaling and cytoskeletal dynamics modulation in podocytes. Further research is required to elucidate the detailed mechanisms of zinc action and its implications in renal health and disease.

Chrysophanol Induces Cell Death and Inhibits Invasiveness through Alteration of Calcium Levels in HepG2 Human Liver Cancer Cells.

To investigate the effect of chrysophanol, a phytochemical derived from Radix et Rhizoma Rhei on HepG2 liver cancer cells. HepG2 cell line was treated with different concentrations chrysophanol (0-100 μmol/L) for 24 h. The cell counting kit 8 assay was employed to assess cell viability. Intracellular calcium levels were examined using Fluo-4 AM and Mag-fluo-4 AM staining, followed by flow cytometry analysis. Mitochondrial membrane potential was measured with JC-1 assay kit. Additionally, the expressions of key proteins such as p-JNK, Bax, cytochrome c (Cyt C), cleaved caspase-3 (cCaspase-3), and caspase-8 were analyzed by Western blot. The inhibitory effects of chrysophanol on the invasion of cells were determined using a Transwell assay. Analysis of invasiveness was conducted by wound healing assay. Chrysophanol significantly reduced the proliferation of HepG2 liver cancer cells by affecting intracellular calcium distribution, diminishing mitochondrial membrane potential, and enhancing the expressions of p-JNK, Bax, Cyt C, cCaspase-3, and caspase-8 in the groups treated with 75 or 100 μmol/L chrysophanol compared to the control group (P<0.05). Additionally, 75 and 100 μmol/L chrysophanol exhibited inhibitory effects on cell migration and wound healing. Chrysophanol demonstrates potential against HepG2 liver cancer cells, suggesting its potential use as a therapeutic agent for liver cancer treatment.

Unraveling the interaction between lead and calcium in occupationally exposed males: an exploratory observation study.

The systemic illnesses associated with chronic lead exposure are partially explained by the interaction between lead and calcium metabolism. Lead exposure is posited to alter calcium levels either by altering calcium homeostasis markers or altering bone remodeling. The present study investigated the interaction between blood lead levels and calcium homeostasis markers and bone remodeling markers among lead-smelting plant workers. Adult male workers employed at the lead-smelting plant were clinically investigated as part of their regular occupational health assessment program. Additionally, control participants without occupational lead exposure, employed in administrative and white-collar jobs were invited to participate in the study. Sociodemographic and occupational details were collected by pre-standardized semi-structured questionnaires from all consenting participants, followed by clinical examination and blood collection. Blood lead levels were estimated using microwave-assisted acid digestion and the inductively coupled plasma mass spectrometry technique. Serum calcium and total protein and alkaline phosphatase levels were estimated as per standard biochemical techniques. 25-hydroxy vitamin-D3, calcitriol, and osteocalcin were estimated using the enzyme-linked immunosorbent assay. In addition to comparative analysis for comparing the two groups, independent linear regression models were explored to investigate the associations between serum calcium and blood lead and osteocalcin levels. A total of 189 lead-exposed men employed at the lead-smelting plant and 25 male control participants consented to participate. The two groups were similar in age, diet, and body mass index. Occupationally exposed individuals exhibited significantly lower serum calcium and higher bone remodeling markers (osteocalcin and alkaline phosphatase) as compared to controls. However, the serum 25-hydroxy vitamin-D3 and calcitriol levels were not significantly different between the two groups. Lastly, the serum lead and osteocalcin were weakly but significantly associated with serum calcium levels after controlling for variations in total protein, diet, 25-hydroxy vitamin-D3, calcitriol, and alkaline phosphatase in the study participants. Current observations reinforce the adverse role of lead exposure on calcium metabolism. Although lead exposure is posited to affect calcium metabolism by multiple pathways, current study observations favor the bone remodeling pathway. The observations recommend periodic screening for calcium and bone health among lead-exposed adults.

Astrocytes as a Therapeutic Target in Alzheimer's Disease-Comprehensive Review and Recent Developments.

Alzheimer's disease (AD) is a frequent and disabling neurodegenerative disorder, in which astrocytes participate in several pathophysiological processes including neuroinflammation, excitotoxicity, oxidative stress and lipid metabolism (along with a critical role in apolipoprotein E function). Current evidence shows that astrocytes have both neuroprotective and neurotoxic effects depending on the disease stage and microenvironmental factors. Furthermore, astrocytes appear to be affected by the presence of amyloid-beta (Aβ), with alterations in calcium levels, gliotransmission and proinflammatory activity via RAGE-NF-κB pathway. In addition, astrocytes play an important role in the metabolism of tau and clearance of Aβ through the glymphatic system. In this review, we will discuss novel pharmacological and non-pharmacological treatments focused on astrocytes as therapeutic targets for AD. These interventions include effects on anti-inflammatory/antioxidant systems, glutamate activity, lipid metabolism, neurovascular coupling and glymphatic system, calcium dysregulation, and in the release of peptides which affects glial and neuronal function. According to the AD stage, these therapies may be of benefit in either preventing or delaying the progression of the disease.

Caloric Intake and its Effect on Aging and Cognitive Slowing: A Review of the Research into Intermittent Fasting

Aging has been defined as the biological changes occurring during a lifetime that result in a decreased resistance to cellular stress, more vulnerability to disease, and increased likelihood of death. Some mechanisms of aging that will be discussed in this paper include instability of genomes, neuroendocrine secreted factors, production of reactive oxygen species, altered calcium levels, and inflammation. Aging rates are species-specific, which suggests a strong genetic influence. However, one major variable shown to affect the rate of aging in many different species is caloric intake.

An inhibitor-mediated beta-cell dedifferentiation model reveals distinct roles for FoxO1 in glucagon repression and insulin maturation

ObjectiveThe loss of forkhead box protein O1 (FoxO1) signaling in response to metabolic stress contributes to the etiology of type II diabetes, causing the dedifferentiation of pancreatic beta cells to a cell type reminiscent of endocrine progenitors. Lack of methods to easily model this process in vitro, however, have hindered progress into the identification of key downstream targets and potential inhibitors. We therefore aimed to establish such an in vitro cellular dedifferentiation model and apply it to identify novel agents involved in the maintenance of beta-cell identity. MethodsThe murine beta-cell line, Min6, was used for primary experiments and high-content screening. Screens encompassed a library of small-molecule drugs representing the chemical and target space of all FDA-approved small molecules with an automated immunofluorescence readout. Validation experiments were performed in a murine alpha-cell line as well as in primary murine and human diabetic islets. Developmental effects were studied in zebrafish and C. elegans models, while diabetic db/db mouse models were used to elucidate global glucose metabolism outcomes. ResultsWe show that short-term pharmacological FoxO1 inhibition can model beta-cell dedifferentiation by downregulating beta-cell-specific transcription factors, resulting in the aberrant expression of progenitor genes and the alpha-cell marker glucagon. From a high-content screen, we identified loperamide as a small molecule that can prevent FoxO inhibitor-induced glucagon expression and further stimulate insulin protein processing and secretion by altering calcium levels, intracellular pH, and FoxO1 localization. ConclusionsOur study provides novel models, molecular targets, and drug candidates for studying and preventing beta-cell dedifferentiation.

Heavy metal stress in rice: Uptake, transport, signaling, and tolerance mechanisms.

Heavy metal contamination of agricultural fields has become a global concern as it causes a direct impact on human health. Rice is the major food crop for almost half of the world population and is grown under diverse environmental conditions, including heavy metal-contaminated soil. In recent years, the impact of heavy metal contamination on rice yield and grain quality has been shown through multiple approaches. In this review article, different aspects of heavy metal stress, that is uptake, transport, signaling and tolerance mechanisms, are comprehensively discussed with special emphasis on rice. For uptake, some of the transporters have specificity to one or two metal ions, whereas many other transporters are able to transport many different ions. After uptake, the intercellular signaling is mediated through different signaling pathways involving the regulation of various hormones, alteration of calcium levels, and the activation of mitogen-activated protein kinases. Heavy metal stress signals from various intermediate molecules activate various transcription factors, which triggers the expression of various antioxidant enzymes. Activated antioxidant enzymes then scavenge various reactive oxygen species, which eventually leads to stress tolerance in plants. Non-enzymatic antioxidants, such as ascorbate, metalloids, and even metal-binding peptides (metallothionein and phytochelatin) can also help to reduce metal toxicity in plants. Genetic engineering has been successfully used in rice and many other crops to increase metal tolerance and reduce heavy metals accumulation. A comprehensive understanding of uptake, transport, signaling, and tolerance mechanisms will help to grow rice plants in agricultural fields with less heavy metal accumulation in grains.

Calpain-Inhibitors Protect Frataxin-Deficient Dorsal Root Ganglia Neurons from Loss of Mitochondrial Na+/Ca2+ Exchanger, NCLX, and Apoptosis.

Calpains are calcium-dependent proteases activated in apoptotic cell death and neurodegeneration. Friedreich Ataxia is a neurodegenerative rare disease caused by frataxin deficiency, a mitochondrial protein. Dorsal root ganglion (DRG) sensory neurons are among the cellular types most affected in this disease. We have previously demonstrated that frataxin-deficient DRGs show calpain activation, alteration in calcium levels and decreased content of the Na+/Ca2+ exchanger (NCLX). This transporter is involved in mitochondrial calcium efflux. In this study, we have performed a time-course analysis of several parameters altered in a frataxin-deficient DRGs. These include decline of NCLX levels, calcium accumulation, mitochondrial depolarization, α-fodrin fragmentation and apoptotic cell death. Furthermore, we have analysed the effect of the calpain inhibitors MDL28170 and Calpeptin on these parameters. We have observed that these inhibitors increase NCLX levels, protect sensory neurons from neurite degeneration and calcium accumulation, and restore mitochondrial membrane potential. In addition, calpain 1 reduction alleviated neurodegeneration in frataxin-deficient DRG neurons. These results strengthen the hypothesis of a central role for calcium homeostasis and calpains in frataxin-deficient dorsal root ganglia neurons.

Elucidating the Role of K+ Channels during In Vitro Capacitation of Boar Spermatozoa: Do SLO1 Channels Play a Crucial Role?

This study sought to identify and localize SLO1 channels in boar spermatozoa by immunoblotting and immunofluorescence, and to determine their physiological role during in vitro sperm capacitation. Sperm samples from 14 boars were incubated in a capacitation medium for 300 min in the presence of paxilline (PAX), a specific SLO1-channel blocker, added either at 0 min or after 240 min of incubation. Negative controls were incubated in capacitation medium, and positive controls in capacitation medium plus tetraethyl ammonium (TEA), a general K+-channel blocker, also added at 0 min or after 240 min of incubation. In all samples, acrosome exocytosis was triggered with progesterone after 240 min of incubation. Sperm motility and kinematics, integrity of plasma and acrosome membranes, membrane lipid disorder, intracellular calcium levels and acrosin activity were evaluated after 0, 60, 120, 180, 240, 250, 270 and 300 min of incubation. In boar spermatozoa, SLO1 channels were found to have 80 kDa and be localized in the anterior postacrosomal region and the mid and principal piece of the tail; their specific blockage through PAX resulted in altered calcium levels and acrosome exocytosis. As expected, TEA blocker impaired in vitro sperm capacitation, by altering sperm motility and kinematics and calcium levels. In conclusion, SLO1 channels are crucial for the acrosome exocytosis induced by progesterone in in vitro capacitated boar spermatozoa.

Tenofovir Disoproxil Fumarate Is Associated with a Set-Point Variation in the Calcium-Parathyroid Hormone-Vitamin D Axis: Results from a German Cohort.

Background Higher levels of parathyroid hormone have been associated with the use of tenofovir disoproxil fumarate (TDF) in people with and without HIV infection. Yet, alterations in calcium levels have never been elucidated in detail. Objective To compare the association of parathyroid hormone with serum calcium levels and other markers of calcium and bone metabolism in people living with HIV on TDF- and non-TDF-containing antiretroviral therapy. Patients and Methods A retrospective single center cohort study in Munich, Germany. Median and interquartile ranges and absolute and relative frequencies were used to describe continuous and categorical variables, respectively. The Mann–Whitney U test and chi2-test were used for comparisons. Multivariate median regression was performed in a stepwise backward approach. Results 1,002 patients were included (786 (78.4%) male; median age 48 (40–55) years). 564 patients (56.3%) had a TDF-containing ART regimen. PTH concentrations were 46.9 (33.0–64.7) pg/mL and 35.2 (26.4–55.4) pg/mL (P=0.001), 43.3 (30.8–59.8) pg/mL and 31.8 (22.3–49.6) pg/mL (P < 0.001), 46.1 (29.5–65.4) pg/mL and 33.4 (22.6–50.1) pg/mL (P < 0.001), and 37.8 (25.3–57.9) pg/mL and 33.8 (20.1–45.3) pg/mL (P=0.012) within the first, second, third, and fourth quartile of corrected calcium levels for patients with and without TDF-containing ART, respectively. In multivariate median regression, PTH concentration was significantly associated with Cacorr. (−32.2 (−49.8 to −14.8); P < 0.001), female sex (5.2 (1.2–9.2); P=0.010), 25(OH)D (−0.4 (−0.5 to −0.3); P < 0.001), and TDF-use (9.2 (6.0–12.5); P < 0.001). Discussion Higher levels of PTH seem to be needed to maintain normal calcium levels in PLWH on TDF-containing ART compared to non-TDF-containing ART. Optimal concentrations for 25-hydroxy vitamin D and calcium might therefore be different in people using TDF than expected from general populations but also people living with HIV with non-TDF-containing antiretroviral therapy. This might require different supplementation strategies but warrants further investigation.

Estimation of serum calcium in sub clinical hypothyroid females of different age groups in Kanchipuram population

Background: Thyroid hormones play an important role in the homeostasis of calcium and phosphorous levels. A person with thyroid dysfunction may exhibit symptoms that are owing to the alteration in calcium levels. Aim: To find out the calcium alteration in hypothyroidism with different age groups in Kanchipuram district. Methodology: In this study 40 patients with the age group of 20-60 y were taken. The parameters like TSH and Ca2+ were estimated with commercially available kits. Results: In our study out of 40 patients 18 patients with hypothyroidism had hypocalcemia, which constitute 45% (n=18) of the study had less serum calcium. Remaining 55% patients having normal calcium levels, In future it may develop hypocalcaemia. Discussion and Conclusion: Total calcium levels in serum were found to be significantly lower in hypothyroid patients in all age groups. This study concluded that, in Kanchipuram district patients have low levels of serum calcium in hypothyroidism. S.Ca++ in hypothyroid people demonstrates a constructive connection between the S.Ca++ and serum TSH. These fluctuations of serum calcium ought to be considered in treating the patients with hypothyroidism by therapeutic experts.

Hypotensive and vasorelaxant effect of Diapocynin in normotensive rats

Nicotinamide adenine dinucleotide phosphate oxidase (NAD(P)H-oxidase) is a multicomponent enzyme system that generates superoxide anion by one-electron reduction of molecular oxygen and represents the major source of reactive oxygen species (ROS) in the vascular cells. Apocynin has been extensively used as an inhibitor of NADPH oxidase (NOX) in phagocytic cells and as an antioxidant in non-phagocytic cells. In phagocytes cells, due to the presence of myeloperoxidase, apocynin can be the converted to diapocynin, which is supposed to be the active form of this phytochemical. Moreover, apocynin was shown to induce hypotension and vasodilatation in many experimental animal models. However, there are no studies showing the effects of diapocynin on blood pressure or in vascular cells. In this present study, we used chemically synthesized diapocynin and analyzed its antioxidant capacity, effect on blood pressure and vascular reactivity. Moreover, it was evaluated the levels of nitric oxide (NO), ROS and calcium in aortic endothelial cells stimulated by diapocynin. All results were compared to apocynin. We found that diapocynin showed higher antioxidant capacity than apocynin. Apocynin and diapocynin, promoted hypotensive effects without changing the heart rate, however the effects of diapocynin were reversed faster than the effects of apocynin, which was long lasting. Diapocynin and apocynin induced endothelium dependent and independent vasodilatation, but diapocynin was less potent than apocynin regarding the capacity of induction of vasodilatation in mesenteric resistance arteries and aorta from Wistar rats. The relaxation induced by apocynin or diapocynin involves sGC and potassium channels in vascular smooth muscle cells and NOS participates of relaxation induced by apocynin or diapocynin in intact mesenteric rings. Apocynin and diapocynin increased NO and decreased ROS levels in endothelial cells, however diapocynin did not alter calcium levels in these cells. In conclusion, these results demonstrated that, similarly to apocynin, diapocynin also induces hypotensive and vasodilator effects in rats and vascular endothelium improves the diapocynin vasodilator effects by increases NO bioavailability.

Ophiobolin A, a sesterpenoid fungal phytotoxin, displays different mechanisms of cell death in mammalian cells depending upon the cancer cell origin.

Herein we have undertaken a systematic analysis of the effects of the fungal derivative ophiobolin A (OphA) on eight cancer cell lines from different tissue types. The LD50 for each cell line was determined and the change in cell size determined. Flow cytometric analysis and western blotting were used to assess the cell death markers for early apoptosis, late apoptosis and necrosis, and the involvement of the caspase signalling pathway. Alterations in calcium levels and reactive oxygen species were assessed due to their integral involvement in intracellular signalling. Subsequently, the endoplasmic reticulum (ER) and mitochondrial responses were investigated more closely. The extent of ER swelling, and the upregulation of proteins involved in the unfolded protein responses (UPR) were seen to vary according to cell line. The mitochondria were also shown to behave differently in response to the OphA in the different cell lines in terms of the change in membrane potential, the total area of mitochondria in the cell and the number of mitochondrial bifurcations. The data obtained in the present study indicate that the cancer cell lines tested are unable to successfully activate the ER stress/UPR responses, and that the mitochondria appear to be a central player in OphA-induced cancer cell death.

Modulation of fatty acids and hydrocarbons in Anabaena 7120 and its ntcA mutant under calcium.

Calcium being a signaling molecule and mediator of cell response, we examined the modulation in fatty acid and hydrocarbon profiles of wild type cyanobacterium Anabaena sp. PCC 7120 and its ntcA mutant under the influence of different calcium chloride concentrations (0-10 mM). Dynamic modifications in fatty acid and hydrocarbon profile were evident through GC-FID analysis of extracted lipids. In the wild type, increase in CaCl2 (10 mM) resulted in unsaturation of fatty acids (observed in terms of high MUFA/PUFA ratio) while hydrocarbon production was distinctly high in the mutant strain compared to wild type at all tested concentrations. The synthesis of short chain hydrocarbons (C5-C8) were dominated at inhibitory concentration (10 mM CaCl2) in mutant strain. Results suggest that the increase in MUFA/PUFA ratio at inhibitory concentration in wild type, and higher percentage of hydrocarbons in mutant strain, may be attributed to the survival and acclimation strategies under altered calcium environment. Our results also suggest the involvement of the ntcA gene (master regulator of N2 metabolism) in regulation of carbon metabolism; specifically fatty acid, hydrocarbon, and other metabolic compounds essential for maintenance and sustenance of growth under stress condition. Thus, our study outlines basic acclimation response along with possibilities of production of fatty acid and hydrocarbon derived biofuel and other bioactive compounds in Anabaena sp. PCC 7120 under altered calcium levels which could be of biotechnological interest.

A comparative study of the ionic and total calcium levels in women with thyroid dysfunction

Background: Thyroid hormones play an important role in the homeostasis of calcium and phosphorous levels. A person with thyroid dysfunction may exhibit symptoms that are owing to the alteration in calcium levels. Objective: To evaluate the effect of thyroid function on the total and ionic calcium levels in women with thyroid dysfunction. Materials and Methods: The study group included three groups: group I (clinically proven healthy controls), group II (hyperthyroidism), and group III (hypothyroidism) with 45 subjects in each group. Estimation of the biochemical parameters was done by standard methods, and the level of ionic calcium was calculated using a formula. Result: Serum total calcium and ionic calcium were significantly decreased in hypothyroidism group subjects when compared with hyperthyroidism and healthy control subjects. In groups II and III, the total calcium was inversely correlated with the thyroid stimulating hormone level. Conclusion: Our study showed that there is an association between the serum calcium levels and thyroid function. However, there is no marked difference between the total and ionic calcium levels in thyroid dysfunction.

Increased calcium in neurons in the cerebral cortex and cerebellum is not associated with cell loss in the mdx mouse model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease resulting from mutation of the X-linked dystrophin gene. In addition to skeletal muscle pathology, cognitive deficits have been identified in patients with DMD. There is a lack of research investigating the pathological mechanisms underlying the neurological deficits apparent in DMD. The current study assessed whether increases in calcium contributed towards neuronal cell loss or histopathological changes in the genetically homologous mdx mouse model of DMD in sections from the cerebral cortex, hippocampus and cerebellum at 24 days, 12 weeks and 9 months of age. Alizarin S staining showed a significant increase in calcium-positive neurons in the mdx cerebral cortex at 24 days and 9 months and the cerebellum at 24 days, 12 weeks and 9 months compared with age-matched controls. However, neuronal cell counts of haemotoxylin and eosin-stained sections showed that altered calcium levels did not lead to neuronal cell loss. A better understanding of how the disruption of calcium regulation affects the function of neurons may explain the neurological deficits apparent in mdx mice and patients with DMD.

Calcium-mediated histone modifications regulate alternative splicing in cardiomyocytes.

In cardiomyocytes, calcium is known to control gene expression at the level of transcription, whereas its role in regulating alternative splicing has not been explored. Here we report that, in mouse primary or embryonic stem cell-derived cardiomyocytes, increased calcium levels induce robust and reversible skipping of several alternative exons from endogenously expressed genes. Interestingly, we demonstrate a calcium-mediated splicing regulatory mechanism that depends on changes of histone modifications. Specifically, the regulation occurs through changes in calcium-responsive kinase activities that lead to alterations in histone modifications and subsequent changes in the transcriptional elongation rate and exon skipping. We demonstrate that increased intracellular calcium levels lead to histone hyperacetylation along the body of the genes containing calcium-responsive alternative exons by disrupting the histone deacetylase-to-histone acetyltransferase balance in the nucleus. Consequently, the RNA polymerase II elongation rate increases significantly on those genes, resulting in skipping of the alternative exons. These studies reveal a mechanism by which calcium-level changes in cardiomyocytes impact on the output of gene expression through altering alternative pre-mRNA splicing patterns.

A case of strio-pallido-dentate calcinosis associated with micromolecular myeloma

Fahr’s disease (FD) is a neurodegenerative disease whose aetiology is unknown, characterized by neuropsychiatric and motor problems associated with symmetrical, bilateral calcification of the basal ganglia. A drop in the metabolism and cerebral flow is deemed to be responsible for the onset of psychiatric and motor problems, cognitive deficit, painful symptoms and altered state of consciousness. The term Fahr’s syndrome (FS) is used when an etiological cause responsible for calcification can be identified. Fahr’s syndrome is associated with extremely diverse clinical conditions: calcium/phosphate metabolism disorders (hypo-hyperparathyroidism, pseudo-hypoparathyroidism), systemic lupus erythematosus, encephalitis and neoplasms [1]. Here, we describe clinical and radiological findings of a case of FS associated with micromolecular myeloma and hypothesize that bone remodelling could encourage the depositing of calcium at an intracerebral level as a result of an increase in the levels of alkaline phosphatase (ALP) and alteration of calcium levels. In January 2013, an 82-year-old woman was admitted to our hospital. The patient’s medical records showed a condition of severe osteoporosis with multiple collapsed vertebrae, dysphagia and rapidly ingravescent cognitive impairment over the last 18 months. No motor problems or psychiatric disturbances were reported. An acute onset of drowsiness made it necessary to hospitalize the patient, who appeared to be in generally serious conditions (Glasgow coma score (GCS) 10/15), and prompted us to perform a brain CT. The brain CT scan was negative regarding focal densitometric alterations and localized accumulation of blood, but showed dystrophic calcification of the dentate nuclei with bilateral occipital cortical calcification at the level of the calcarine cortex, as seen in FD (Fig. 1). Blood chemistry analysis also showed: kidney failure (GFR 13 ml/min); anaemia (Hb 9.5 g/dl; n.v. 12–16 g/dl); hypercalcaemia (13.3 mg/dl; n.v. 8.40–10 mg/dl) and hyperphosphatemia (5.9 mg/dl; n.v. 2.8–4.6 mg/dl); increase of ALP (123 U/l; n.v. 35–104 U/l) and inflammatory markers (VES 69 mm/h; n.v. 0–35 mm/h; PCR 18,600 lg/l; n.v. \5,000 lg/l). Protein electrophoresis test showed hypoalbuminemia (33.8 g/l; n.v. 40.2–47.6 g/l), increase of acute phase proteins and hypogammaglobulinemia (8 % n.v. 11.1–18.8 %). Alterations of the calcium and phosphate metabolism are the most common cause of FS. In our patient, the concomitance of calcification of the basal ganglia and hypercalcaemia led us to suspect a condition of secondary FS and hyperparathyroidism, but subsequent serum assays for parathormone (PTH) (40.7 pg/ml; n.v.15–65 pg/ml) and vitamin D (31 ng/ml; n.v. [30 ng/ml) were normal in both cases. During the clinical course, the patient was less drowsy and suffered extremely painful symptoms, visual analogue scale (VAS) 10/10; worsening renal function was also noted. Even though drowsiness and painful symptoms could be attributed to cerebral calcification, was ingravescent kidney failure simply a concomitant pathological condition or was there a link among the clinical picture, calcification of basal ganglia and renal dysfunction? A 24-h urine collection showed significant proteinuria (2,777 mg/ 24 h; n.v. 40–150 mg/24). The finding of proteinuria in the N. Gueli W. Verrusio (&) V. M. Magro M. Zaccone M. Cacciafesta Department of Anesthesiological, Cardiovascular, Respiratory, Nephrological, and Geriatric Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy e-mail: walter.verrusio@uniroma1.it

Calcium‐mediated regulation of the Ran gradient and karyopherin nuclear transport receptors.

Several cellular stresses, such as UV radiation, heat shock, and oxidative or hyperosmotic stress can cause a disruption of two key regulators of nuclear protein transport, the Ran gradient and karyopherin transport factors. We have demonstrated that cellular stress induced by increasing cellular calcium, either by the introduction of Thapsigargin, an inhibitor of Ca2&amp;#8314; uptake into the endoplasmic reticulum, or Ionomycin, which releases calcium from the endoplasmic reticulum, disrupts nuclear transport in HeLa cells. We sought to determine if variation of cellular calcium levels affected nuclear transport through alterations of Ran or karyopherins. We revealed that altering calcium levels leads to an accumulation of Ran in the cytoplasm. Additionally, cells treated with thapsigargin or ionomycin experience relocation of several karyopherins such as Crm1, Importin alpha, Importin beta, and Transportin. Persistent exposure to either drug leads to cellular death. However, the disruption of the Ran gradient can be reversed and rescue is enhanced by the presence of a calcium chelator, BAPTA. These results suggest that alteration of cellular calcium levels, causes the localization of Ran to be disrupted along with that of the nuclear transport factors, suggesting that their is indeed a role for calcium as a regulator in the traditional Ran‐mediated nuclear transport pathways.

Cellular Autofluorescence following Ionizing Radiation

Cells often autofluoresce in response to UV radiation excitation and this can reflect critical aspects of cellular metabolism. Here we report that many different human and murine cell types respond to ionizing radiation with a striking rise in autofluorescence that is dependent on dose and time. There was a highly reproducible fluorescent shift at various wavelengths, which was mirrored by an equally reproducible rise in the vital intracellular metabolic co-factors FAD and NADH. It appears that mitochondria, metabolism and Ca2+ homeostasis are important for this to occur as cells without mitochondria or cells unable to alter calcium levels did not behave in this way. We believe these radiation-induced changes are of biological importance and that autofluorescence may even provide us with a tool to monitor radiation responses in the clinic.