Atypical presentation of pulmonary embolism and deep vein thrombosis due to protein S deficiency in a young female with chest pain

Venous thromboembolism has many risk factors including protein S deficiency, which poses a significant diagnostic challenge as it presents with atypical complaints. A treatable yet potentially fatal condition, acute pulmonary embolism, is currently third most common cause of cardiovascular death. Clinicians should include pulmonary embolism as differential diagnosis in young adults with atypical symptoms with 2 D ECHO findings of the dilated right atrium, right ventricle, and elevated pulmonary artery pressure, and diagnosis is confirmed by computed tomography pulmonary angiography (CTPA). Anticoagulants including NOACs should be initiated promptly to improve the outcome for patients.

All India Ophthalmological Society (AIOS) Task Force guidelines to prevent intraocular infections and cluster outbreaks after cataract surgery

Infectious endophthalmitis is a serious and vision-threatening complication of commonly performed intraocular surgeries such as cataract surgery. The occurrence of endophthalmitis can result in severe damage to the uveal and other ocular tissues even among patients undergoing an uncomplicated surgical procedure. If the infections result from common factors such as surgical supplies, operative or operation theater-related risks, there can be a cluster outbreak of toxic anterior segment syndrome (TASS) or infectious endophthalmitis, leading to several patients having an undesirable outcome. Since prevention of intraocular infections is of paramount importance to ophthalmic surgeons, the All India Ophthalmological Society (AIOS) has taken the lead in the formation of a National Task Force to help ophthalmic surgeons apply certain universal precautions in their clinical practice. The Task Force has prepared a handy checklist and evidence-based guidelines to minimize the risk of infectious endophthalmitis following cataract surgery.

The perceived impact of webinars during the COVID.19 pandemic: A survey of ophthalmology trainees from India

OBJECTIVE

The objective of the study was to assess the perceived utility and the impact of web-based teaching programs being conducted following the COVID-19 pandemic.

METHODS

An online survey was sent to trainee ophthalmologists across India through various social media platforms. The responses were tabulated and analyzed.

RESULTS

A total of 768 valid responses were recorded. Majority of respondents (52.2%) felt that the ideal duration for webinars was 1 hour or less. Factors that helped trainees in choosing a webinar were the topic (95.1%), the timing (53.6%), and the speaker list (42.4%). Residents indicated a preference for webinars to attend aimed at postgraduate residency training, more specifically clinical problem-solving. Further questions were answered using a 1-10 Likert scale (1: least useful and 10: extremely useful). The median score when asked for overall usefulness of the webinars in general was 8 (interquartile range/IQR: 2). The median response when asked about utility of webinars in enhancing theoretical knowledge was 8 (IQR: 2) and the median for utility of webinar-based teaching programs in enhancing practical knowledge/surgical learning was also 8 (IQR: 2). The median score when asked about the utility of the webinar programs in acquiring skills for writing research papers/thesis was 7 (IQR: 3). Connectivity issues, audio/voice issues, and the long duration of webinars were some of the problems faced while attending webinars.

CONCLUSIONS

Ophthalmology trainees in India found online teaching programs and webinars to be useful in enhancing their theoretical knowledge and practical skills/surgical learning. Administrators and educational institutes should tailor online teaching programs as per the needs and preferences of the residents.

A national curriculum for ophthalmology residency training

We present a residency curriculum for Ophthalmology in India. The document derives from a workshop by the All India Ophthalmological Society (AlOS) which adapted the International Council of Ophthalmology residency curriculum and refined and customized it based on inputs by the residency program directors who participated in the work shop. The curriculum describes the course content, lays down the minimum requirements of infrastructure and mandates diagnostic and therapeutic procedures required for optimal training. It emphasises professionalism, management, research methodology, community ophthalmology as integral to the curriculum. The proposed national ophthalmology residency curriculum for India incorporates the required knowledge and skills for effective and safe practice of ophthalmology and takes into account the specific needs of the country.

Negative velocity fluctuations and non-equilibrium fluctuation relation for a driven high critical current vortex state

Under the influence of a constant drive the moving vortex state in 2H-NbS₂ superconductor exhibits a negative differential resistance (NDR) transition from a steady flow to an immobile state. This state possesses a high depinning current threshold (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich) with unconventional depinning characteristics. At currents well above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich, the moving vortex state exhibits a multimodal velocity distribution which is characteristic of vortex flow instabilities in the NDR regime. However at lower currents which are just above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich, the velocity distribution is non-Gaussian with a tail extending to significant negative velocity values. These unusual negative velocity events correspond to vortices drifting opposite to the driving force direction. We show that this distribution obeys the Gallavotti-Cohen Non-Equilibrium Fluctuation Relation (GC-NEFR). Just above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich, we also find a high vortex density fluctuating driven state not obeying the conventional GC-NEFR. The GC-NEFR analysis provides a measure of an effective energy scale (E_eff) associated with the driven vortex state. The E_eff corresponds to the average energy dissipated by the fluctuating vortex state above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich. We propose the high E_eff value corresponds to the onset of high energy dynamic instabilities in this driven vortex state just above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich.

Study of the sign change of exchange bias across the spin reorientation transition in Co(Cr1-x Fe x )2O4 (x = 0.00-0.125)

We present the evolution of novel phenomena of magnetic compensation effect, exchange bias (EB) effect and the field induced anomalies in '[Formula: see text]' substituted multiferroic compound [Formula: see text]. A few percent of '[Formula: see text]' substitution for '[Formula: see text]' in [Formula: see text] results in the reversal of field cooled magnetization under low applied fields below compensation temperature T _comp. Further, increase in the field leads to the spin reorientation transition (T _SR). Signature of EB in a narrow temperature window in the vicinity of T _SR and its sign change across T _SR is observed. Magnitude of EB depends on the amount of compensation and rigidity of the spin reorientation. We also notice the appearance of positive EB below the lock-in transition (T _L). Presence of unidirectional anisotropy developed in the commensurate spin-spiral below T _L could be responsible for the appearance of EB below T _L.

Antioxidant Supplements and Gastrointestinal Diseases: A Critical Appraisal

The gastrointestinal tract digests and absorbs dietary nutrients, protects the body against physical and chemical damage from contents in its lumen, provides immunity against external antigens, and keeps an optimum environment for the gut microbiota. These functions cannot be performed normally in several diseases of which the following are discussed here: irritable bowel syndrome and inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. Because these diseases are associated with oxidative stress, a host of antioxidant supplements are used for maintenance and recovery of the gut functions. However, the benefits of these supplements have not been established. The available 80 human trials were rated for levels of confidence and for benefits of the antioxidant supplements. For Crohn's disease, the supplements for which clear benefits occurred in at least 2 studies were allopurinol, Boswellia serrata (frankincense or shallaki), Artemesia species (wormwood), Tripterygium wilfordii (léi gōng téng), and omega-3 fatty acids. Similar beneficial supplements for ulcerative colitis were allopurinol, Matricaria chamomilla (chamomile), Curcuma longa (curcumin in turmeric), and omega-3 fatty acids. There was also a clear benefit for ulcerative colitis in 2 studies where a multiherbal Chinese medicine preparation and an Ayurvedic medicine preparation were used. For irritable bowel syndrome, there was only a marginal benefit of some of the antioxidant supplements. Thus, some antioxidant supplements may be beneficial at certain stages of specific diseases. This is consistent with the current concept that antioxidants act by inhibiting oxidative stress pathways in a tissue- and environment-specific manner and not by simply acting as scavengers.

Sodium-Calcium Exchanger in Pig Coronary Artery

This review focuses on the sodium-calcium exchangers (NCX) in the left anterior descending coronary artery smooth muscle. Bathing tissues in Na⁺-substituted solutions caused them to contract. In cultured smooth muscle cells, it increased the cytosolic Ca²⁺ concentration and extracellular entry of ⁴⁵Ca²⁺. All three activities were attributed to NCX since they were inhibited by NCX inhibitors. The tissues also expressed the sarco/endoplasmic reticulum (SER) Ca²⁺ pump SERCA2b whose activity was much greater than that of NCX. Inhibiting SERCA2b with thapsigargin decreased the NCX-mediated ⁴⁵Ca²⁺ accumulation by the cells. The decrease was not observed in cells loaded with the Ca²⁺-chelator BAPTA. The results are consistent with a limited diffusional space model with a proximity between NCX and SERCA2b. NCX molecules appear to be colocalized with the subsarcolemmal SERCA2b based on studies on membrane flotation experiments and microscopic fluorescence imaging of antibody-labeled cells. Thapsigargin inhibition of SERCA2b moved NCX even closer to SER. This provides a model for the NCX-mediated Ca²⁺ refilling of SER in the arterial smooth muscle. The model for the NCX-mediated refilling of the depleted SER proposed for smooth muscle did not apply to endothelium in which NCX levels were greater and SERCA levels were lower than in smooth muscle. The effect of thapsigargin on the NCX-mediated Ca²⁺ accumulation which was observed in smooth muscle was absent in the endothelium. We propose that the coupling between NCX and smooth muscle may be tissue dependent.

Benefits of antioxidant supplements for knee osteoarthritis: rationale and reality

Arthritis causes disability due to pain and inflammation in joints. There are many forms of arthritis, one of which is osteoarthritis whose prevalence increases with age. It occurs in various joints including hip, knee and hand with knee osteoarthritis being more prevalent. There is no cure for it. The management strategies include exercise, glucosamine plus chondroitin sulfate and NSAIDs. In vitro and animal studies provide a rationale for the use of antioxidant supplements for its management. This review assesses the reality of the benefits of antioxidant supplements in the management of knee osteoarthritis. Several difficulties were encountered in examining this issue: poorly conducted studies, a lack of uniformity in disease definition and diagnosis, and muddling of conclusions from attempts to isolate the efficacious molecules. The antioxidant supplements with most evidence for benefit for pain relief and function in knee osteoarthritis were based on curcumin and avocado-soya bean unsaponifiables. Boswellia and some herbs used in Ayurvedic and Chinese medicine may also be useful. The benefits of cuisines with the appropriate antioxidants should be assessed because they may be more economical and easier to incorporate into the lifestyle.

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe2

We present here some newer characteristics pertaining to paramagnetic Meissner effect like response in a single crystal of the low [Formula: see text] superconducting compound 2H-[Formula: see text] via a detailed study of effects of perturbation on the field-cooled magnetization response. In the temperature range, where an anomalous paramagnetic magnetization occurs, the field-cooled magnetization response is found to be highly metastable: it displays a curious tendency to switch randomly from a given paramagnetic value to a diamagnetic or to a different paramagnetic value, when the system is perturbed by an impulse of an externally applied ac magnetic field. The new facets revealed in a single crystal of 2H-[Formula: see text] surprisingly bear a marked resemblance with the characteristics of magnetization behaviour anticipated for the giant vortex states with multiple flux quanta ([Formula: see text], [Formula: see text], [Formula: see text]) predicted to occur in mesoscopic-sized superconducting specimen and possible transitions amongst such states.

How effective are antioxidant supplements in obesity and diabetes?

Obesity is a central health issue due to its epidemic prevalence and its association with type 2 diabetes and other comorbidities. Obesity is not just being overweight. It is a metabolic disorder due to the accumulation of excess dietary calories into visceral fat and the release of high concentrations of free fatty acids into various organs. It represents a state of chronic oxidative stress and low-grade inflammation whose intermediary molecules may include leptin, adiponectin and cytokines. It may progress to hyperglycemia, leading to type 2 diabetes. Whether or not dietary antioxidant supplements are useful in the management of obesity and type 2 diabetes is discussed in this review. Only the benefits for obesity and diabetes are examined here. Other health benefits of antioxidants are not considered. There are difficulties in comparing studies in this field because they differ in the time frame, participants' ethnicity, administration of antioxidant supplements, and even in how obesity was measured. However, the literature presents reasonable evidence for marginal benefits of supplementation with zinc, lipoic acid, carnitine, cinnamon, green tea, and possibly vitamin C plus E, although the evidence is much weaker for omega-3 polyunsaturated fatty acids, coenzyme Q10, green coffee, resveratrol, or lycopene. Overall, antioxidant supplements are not a panacea to compensate for a fast-food and video-game way of living, but antioxidant-rich foods are recommended as part of the lifestyle. Such antioxidant foods are commonly available.

Use of allosteric targets in the discovery of safer drugs

The need for drugs with fewer side effects cannot be overemphasized. Today, most drugs modify the actions of enzymes, receptors, transporters and other molecules by directly binding to their active (orthosteric) sites. However, orthosteric site configuration is similar in several proteins performing related functions and this leads to a lower specificity of a drug for the desired protein. Consequently, such drugs may have adverse side effects. A new basis of drug discovery is emerging based on the binding of the drug molecules to sites away (allosteric) from the orthosteric sites. It is possible to find allosteric sites which are unique and hence more specific as targets for drug discovery. Of many available examples, two are highlighted here. The first is caloxins - a new class of highly specific inhibitors of plasma membrane Ca²⁺ pumps. The second concerns the modulation of receptors for the neurotransmitter acetylcholine, which binds to 12 types of receptors. Exploitation of allosteric sites has led to the discovery of drugs which can selectively modulate the activation of only 1 (M1 muscarinic) out of the 12 different types of acetylcholine receptors. These drugs are being tested for schizophrenia treatment. It is anticipated that the drug discovery exploiting allosteric sites will lead to more effective therapeutic agents with fewer side effects.

Orbital myeloid sarcoma presenting as massive proptosis

A 10-year-old boy presented with right proptosis for 8 months. The eyeball was grossly pushed down, with diffuse corneal haze and non-reactive pupil. Systemic examination was normal. Previous investigations in another centre included a computerized tomography scan, which showed a well-defined enhancing retro-bulbar mass, a non-contributory fine needle aspiration cytology and a biopsy showing fibrocollagenous tissue with moderate lympho-monocytic infiltrate suggestive of non-specific inflammation. PET-CT scan revealed the presence of enlarged fluoro-deoxyglucose-avid cervical and mesenteric lymph nodes. Biopsy of the retro-bulbar mass was repeated in our centre. It showed fibrocollagenous and skeletal muscle tissue infiltrated by lymphoid follicles, dispersely lying lymphocytes and plasma cells, and admixed large atypical cells with vesicular nuclei, prominent nucleoli and scanty cytoplasm, strongly positive for myeloperoxidase, CD43 and CD99 immunohistochemistry. Hemogram was normal. Bone marrow aspiration/biopsy and CSF showed no evidence of acute myeloid leukemia. The child received chemotherapy in another centre and is in complete remission 6 months after completion.

Why fruits are rich in antioxidants? An opinion review

We rarely consider whether and how plants benefit from making antioxidant-rich fruits, despite our dependence on fruits as routine sources of these compounds. The hypothesis presented here is that storage of the antioxidant materials is advantageous to the survival of the plant species. This hypothesis is based on the premise that at different stages from flower bud opening to seedling formation, the concentrations of the reactive oxygen species (ROS) needed vary tremendously. Exposing seeds of several plant species to ROS aids germination. However, ROS can cause considerable damage by mutagenesis during plant embryogenesis. It is suggested that the antioxidant-rich environment in fruits protects the developing plant embryos from this damage. It also allows for an antioxidant environment for packaging the embryos into seeds with tight seed coats. After fruit maturation and seed dispersal, a prolonged exposure to oxygen and moisture enables the seeds to produce the ROS needed for seed germination. There is a simultaneous increase in the ROS scavenging systems to allow for protection of the dividing cells afterwards. These observations are unified into the hypothesis that the antioxidant rich fruits aid in the survival of plant species, and discussed in the context of vascular plant evolution.

Magnetic response in the vicinity of magnetic compensation: a case study in spin ferromagnetic Sm1 - xGdxAl2 intermetallic alloys

A compensated magnetic state in an ideally homogeneous system with long range magnetic order is characterized by a net zero magnetization (M) throughout the sample (macroscopic). In the pristine state of the sample (i.e. with no external field, H = 0), this implies that at the magnetic compensation temperature (Tcomp) we must have M = 0 at H = 0 irrespective of any thermal and magnetic history of the sample and any underlying physics. This simple fact voids the usual identification (and interpretation) of M-H loop parameters at and in the vicinity of magnetic compensation temperature, specifically the coercivity, the remanence, and the exchange bias characteristics. The physics of coercivity and exchange bias continues to be fully relevant, but its manifestation in an M-H loop would get camouflaged at (and near) a magnetic compensation because [Formula: see text] at H = 0. We present an experimental elucidation of the above premise through a case study in the spin ferromagnetic Sm1 - xGdxAl2 alloys [x = 0.01-0.06], where the specimens with x ≤ 0.03 show compensation below the Curie temperature Tc, while those with x ≥ 0.03 have rather small magnetization due to near cancellation of opposing contributions, but are otherwise devoid of compensation. The experiments comprised low field (near zero) as well as high field (70 kOe) magnetization measurements from the paramagnetic state down to 5 K in the ordered regime (Tc ∼ 125 K) and isothermal M-H loop studies on the remnant magnetic state of polycrystalline samples.

Large low-frequency fluctuations in the velocity of a driven vortex lattice in a single crystal of 2H-NbSe2 superconductor

The driven state of a well-ordered flux line lattice in a single crystal of 2H-NbSe2 in the time domain has revealed the presence of substantial fluctuations in velocity, with large and distinct time periods ( approximately seconds). A superposition of a periodic drive in the driven vortex lattice causes distinct changes in these fluctuations. We propose that prior to the onset of the peak effect there exists a heretofore unexplored regime of coherent dynamics, with unexpected behavior in velocity fluctuations.

Congenital eyelid colobomas in 51 patients

PURPOSE

To review the clinical observations in the management of congenital eyelid coloboma.

METHODS

Fifty-one cases of congenital eyelid colobomas including the functional and cosmetic rehabilitation of patients who were treated over a period of 18 years with an average follow-up of 4.7 years were retrospectively reviewed.

RESULTS

Thirty-eight patients had an upper eyelid coloboma and 13 patients had a lower eyelid coloboma. Systemic associations included Goldenhar syndrome and Treacher-Collins-Franceschetti syndrome. Twenty-two patients with upper eyelid colobomas underwent surgery by direct apposition, eyelid sharing procedures, or a lateral rotation flap. Lower eyelid colobomas were repaired in 4 patients.

CONCLUSION

Gratifying cosmetic and functional results could be achieved in all 26 patients who underwent surgery.

Clinical Anophthalmia With Orbital Heterotopic Brain Tissue

The authors describe the uncommon clinical presentation and treatment of a neonate with progressive proptosis, which turned out to be an ectopic cerebral rest in the orbit in the absence of a formed eye. The discussion examines the theories regarding the genesis of the condition, different locations in the body (including the orbit and the eye) in which ectopic cerebral rests have been described in the literature, and the management of the condition.

Plasma Membrane Calcium Pump Activity in Rat Pancreatic Islets: An Accurate Method to Measure its Calcium-Dependent Modulation

The aim of this study was to quantify the glucose modulation of the plasma membrane calcium pump (PMCA) function in rat pancreatic islets. Ca2+-ATPase activity and levels of phosphorylated PMCA intermediates both transiently declined to a minimum in response to stimulation by glucose. Strictly dependent on Ca2+ concentration, this inhibitory effect was fully expressed at physiological concentrations of the cation (less than 0.5 muM), then progressively diminished at higher concentrations. These results, together with those previously reported on the effects of insulin secretagogues and blockers on the activity, expression and cellular distribution of the PMCA, support the concept that the PMCA plays a key role in the regulation of Ca2+ signaling and insulin secretion in pancreatic islets.

Leber′s hereditary optic neuropathy with molecular characterization in two Indian families

PURPOSE

Leber's hereditary optic neuropathy (LHON) presents in early adulthood with painless progressive blindness of one or both eyes. Usually there is a positive family history of similar disease on the maternal side. Definitive diagnosis can be established by finding the change in the mitochondrial gene. No molecular studies have been reported from India.

MATERIAL AND METHODS

Clinical, ophthalmologic and molecular studies were carried out in two patients from different families and available first degree relatives. The subjects were tested for the three common mutations seen in LHON by molecular techniques of polymerase chain reaction using mutation specific primers.

RESULTS

The mutations G3460A and G11778A in the mitochondrial genes MTND1 and MTND4, known to be causative for LHON, were found in one family each.

CONCLUSION

Diagnosis of LHON should be considered in familial cases and in young adults with optic atrophy. Confirmation of diagnosis should be sought by molecular gene analysis. Genetic counselling should be offered to all 'at risk' relatives of a patient harbouring the mutation.

Mechanism of action of the novel plasma membrane Ca(2+)-pump inhibitor caloxin

Caloxin 2A1 is a novel inhibitor of the plasma membrane (PM) Ca(2+)-pump [Am. J. Physiol. Cell Physiol. 280 (2001) C1027]. The PM Ca(2+)-pump is a Ca(2+)-Mg(2+)-ATPase that expels Ca(2+) from cells to help them maintain low concentrations of cytosolic Ca(2+). Caloxin 2A1 inhibits Ca(2+)-Mg(2+)-ATPase in human erythrocyte leaky ghosts. Here we report that this inhibition is non-competitive with respect to the substrates Ca(2+) and ATP and the activator calmodulin. This was anticipated since the high affinity binding site for Ca(2+) and sites for ATP and calmodulin are intracellular whereas caloxin 2A1 is a peptide selected for binding to the second extracellular domain of the pump. Caloxin 2A1 also inhibited the Ca(2+)-dependent formation of the acid stable 140 kDa acylphosphate intermediate from 32P-gamma-ATP. However, it did not inhibit the formation of the acylphosphate intermediate in the reverse direction-from 32P-orthophosphate. Consistent with results on mutagenesis of transmembrane residues in the pump protein, we suggest that caloxin 2A1 inhibits conformational changes required during the reaction cycle of the pump.

Iron promotes cadmium binding to citrate

Iron-cadmium interactions are important in cadmium toxicity. Dietary iron supplements may decrease cadmium retention after oral cadmium exposure but the underlying mechanism is not known. Using a CdS/AgS ion selective electrode to measure [Cd2+] in physiological saline solution at pH 7.4, we show that Fe2+ promotes Cd2+ binding to citrate thereby decreasing the availability of free Cd2+. This suggests the formation of high molecular weight Cd2+-Fe2+-citrate complexes. We confirm this suggestion by showing that 109Cd2+ is retained by 1 kDa cut off filters when present with total 50 microM Fe2+ plus 1 mM citrate but not when present with citrate alone. The formation of high molecular weight complexes may prevent Cd2+ absorption. As citrate is part of the diet, we suggest that these iron-cadmium interactions may contribute to the protective effect of iron against cadmium toxicity.

Treatment of PC12 cells with nerve growth factor increases iron uptake

Phaeochromocytoma PC12 cells treated with nerve growth factor (NGF) differentiate into a neuronal phenotype. Here we compare the uptake of transferrin-bound and non-transferrin-bound iron in NGF-treated (neuronal phenotype) and control (proliferating) PC12 cells. The non-transferrin-bound iron uptake was greater in the NGF-treated cells than in the control, independently of the uptake time, the iron-chelating agents used, the oxidation state of iron (Fe(2+) or Fe(3+)) and the iron concentration tested. The NGF-treated cells expressed L-type and N-type voltage-operated Ca(2+) channels. Nitrendipine (an L-type inhibitor) and possibly omega-conotoxin (an N-type inhibitor) inhibited the iron uptake by 20%. Thapsigargin inhibits the endoplasmic reticulum Ca(2+) pump and allowed Mn(2+) entry into cells. Preincubating PC12 cells with thapsigargin increased the iron uptake. The rate of transferrin-bound iron uptake was less than 1% of the non-transferrin-bound iron uptake and the maximum transferrin-bound iron uptake was also very low. We conclude that an increase in the iron uptake by multiple pathways accompanies the transition of PC12 cells from the proliferating to the neuronal phenotype.

The role of 3'-untranslated region (3'-UTR) mediated mRNA stability in cardiovascular pathophysiology

Knowledge of transcription and translation has advanced our understanding of cardiac diseases. Here, we present the hypothesis that the stability of mRNA mediated by the 3'-untranslated region (3'-UTR) plays a role in changing gene expression in cardiovascular pathophysiology. Several proteins that bind to sequences in the 3'-UTR of mRNA of cardiovascular targets have been identified. The affected mRNAs include those encoding beta-adrenergic receptors, angiotensin II receptors, endothelial and inducible nitric oxide synthases, cyclooxygenase, endothelial growth factor, tissue necrosis factor (TNF-alpha), globin, elastin, proteins involved in cell cycle regulation, oncogenes, cytokines and lymphokines. We discuss: (a) the types of 3'-UTR sequences involved in mRNA stability, (b) AUF1, HuR and other proteins that bind to these sequences to either stabilize or destabilize the target mRNAs, and (c) the potential role of the 3'-UTR mediated mRNA stability in heart failure, myocardial infarction and hypertension. We hope that these concepts will aid in better understanding cardiovascular diseases and in developing new therapies.

Caloxin: a novel plasma membrane Ca2+ pump inhibitor

Plasma membrane (PM) Ca2+ pump is a Ca+-Mg2+-ATPase that expels Ca2+ from cells to help them maintain low concentrations of cytosolic Ca2+ . There are no known extracellularly acting PM Ca2+ pump inhibitors, as digoxin and ouabain are for Na+ pump. In analogy with digoxin, we define caloxins as extracellular PM Ca2+ pump inhibitors and describe caloxin 2A1. Caloxin 2A1 is a peptide obtained by screening a random peptide phage display library for binding to the second extracellular domain (residues 401-413) sequence of PM Ca2+ pump isoform 1b. Caloxin 2A1 inhibits Ca2+-Mg2+-ATPase in human erythrocyte leaky ghosts, but it does not affect basal Mg2+-ATPase or Na+-K+-ATPase in the ghosts or Ca2+-Mg2+-ATPase in the skeletal muscle sarcoplasmic reticulum. Caloxin 2A1 also inhibits Ca2+-dependent formation of the 140-kDa acid-stable acylphosphate, which is a partial reaction of this enzyme. Consistent with inhibition of the PM Ca2+ pump in vascular endothelium, caloxin 2A1 produces an endothelium-dependent relaxation that is reversed by N(G)-nitro-L-arginine methyl ester. Thus caloxin 2A1 is a novel PM Ca2+ pump inhibitor selected for binding to an extracellular domain.

Transient receptor potential protein mRNA expression in rat substantia nigra

Receptor gated Ca2+ entry has been associated with transient receptor potential (TRP) proteins encoded by several different genes. Here, we compare expression of mRNA for TRP isoforms encoded by genes TRP1-6 in the rat substantia nigra and whole brain. The substantia nigra and the whole brain expressed mRNA predominantly for TRP3 and TRP6. The levels of TRP1, 2, 4 and 5 were very low in both. The TRP6 mRNA levels in substantia nigra and the whole brain were comparable while those for TRP3 were significantly lower in substantia nigra than in the whole brain. Thus substantia nigra differs from the whole brain in its TRP expression.

On the Ca2+ dependence of non-transferrin-bound iron uptake in PC12 cells

Non-transferrin-bound iron (NTBI) uptake has been reported to follow two pathways, Ca(2+)-dependent and Ca(2+)-independent (Wright, T. L., Brissot, P., Ma, W. L., and Weisiger, R. A. (1986) J. Biol. Chem. 261, 10909-10914; Sturrock, A., Alexander, J., Lamb, J., Craven, C. M., and Kaplan, J. (1990) J. Biol. Chem. 265, 3139-3145). Studies reporting the two pathways have ignored the weak interactions of Ca(2+) with the chelator nitrilotriacetate (NTA) and the reducing agent ascorbate. These studies used a constant ratio of total Fe(2+) to NTA with and without Ca(2+). We observed Ca(2+) activation of NTBI uptake in PC12 cells with the characteristics reported for other cells upon using 1 mm ascorbate and a constant ratio of total Fe(2+) to NTA with or without Ca(2+). However, Ca(2+) did not affect NTBI uptake in solutions without NTA. We then determined conditional stability constants for NTA binding to Ca(2+) and Fe(2+) by potentiometry under conditions of NTBI uptake experiments (pH, ionic strength, temperature, ascorbate, total Fe(2+), and total Ca(2+) concentrations). In solutions based on these constants and taking Ca(2+) chelation into account, Ca(2+) did not affect NTBI uptake over a range of free Fe(2+) concentrations. Thus, the Ca(2+) activation of NTBI uptake observed using the constant total Fe(2+) to NTA ratio was because of Ca(2+)-NTA chelation rather than an activation of the NTBI transporter itself. It is suggested that the previously reported Ca(2+) dependence of NTBI uptake be re-evaluated.

Ascorbate transport in pig coronary artery smooth muscle: Na(+) removal and oxidative stress increase loss of accumulated cellular ascorbate

Pig deendothelialized coronary artery rings and smooth muscle cells cultured from them accumulated ascorbate from medium containing Na(+). The accumulated material was determined to be ascorbate using high-performance liquid chromatography. We further characterized ascorbate uptake in the cultured cells. The data fitted best with a Hill coefficient of 1 for ascorbate (K(asc) = 22 +/- 2 microM) and 2 for Na(+) (K(Na) = 84 +/- 10 mM). The anion transport inhibitors sulfinpyrazone and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) inhibited the uptake. Transferring cultured cells loaded with (14)C-ascorbate into an ascorbate-free solution resulted in a biphasic loss of radioactivity - an initial sulfinpyrazone-insensitive faster phase and a late sulfinpyrazone-sensitive slower phase. Transferring loaded cells into a Na(+)-free medium increased the loss in the initial phase in a sulfinpyrazone-sensitive manner, suggesting that the ascorbate transporter is bidirectional. Including peroxide or superoxide in the solution increased the loss of radioactivity. Thus, ascorbate accumulated in coronary artery smooth muscle cells by a Na(+)-dependent transporter was lost in an ascorbate-free solution, and the loss was increased by removing Na(+) from the medium or by oxidative stress.

Effects of hydrogen peroxide on pig coronary artery endothelium

Peroxides and other reactive oxygen species damage arteries during ischemia-reperfusion. Here, we report on the effects of H(2)O(2) on contractility of pig coronary artery. We either treated 3-mm coronary artery rings with 0 to 0.5 mM H(2)O(2) in organ baths or we perfused the arteries with H(2)O(2) and then cut them into rings. In each instance, we monitored the force of contraction of 3-mm rings in H(2)O(2)-free solution with 30 mM KCl and then we determined the A23187 induced endothelium dependent relaxation as a percent of this contraction. Treatment with H(2)O(2) in the organ bath caused a decrease in the contraction but it did not affect the percent relaxation. Treating arteries with H(2)O(2) by luminal perfusion did not affect the contraction but it decreased the percent relaxation. Perfusion alone decreased the amount of endothelium remaining in the arteries and perfusing with H(2)O(2) decreased it further. The percent relaxation with A23187 correlated well with the endothelium remaining in the arteries. We propose that H(2)O(2) and shear stress can cause a loss of endothelium and that endothelium can also protect the underlying smooth muscle against luminal H(2)O(2).

Nerve growth factor treatment alters Ca2+ pump levels in PC12 cells

Nerve growth factor (NGF) treatment converts rapidly dividing PC12 cells into a neuronal phenotype. To understand the Ca2+ sequestration mechanisms accompanying this differentiation, we examined the endoplasmic reticulum Ca2+ (SERCA) pump levels using two different assays: ATP-dependent azide insensitive oxalate stimulated 45Ca2+ uptake by PC12 cells permeabilized with saponin, and Western blots using a monoclonal antibody which reacts with all the SERCA isoforms. We also examined the reaction to an antibody against the plasma membrane Ca2+ (PMCA) pump. NGF treatment decreased the SERCA pump expression but it increased the PMCA pump level. These results are consistent with a greater role of PMCA pumps in neuronal cells than in most other cells and with an increased role of SERCA pumps during cell proliferation.

Catalase activity in coronary artery endothelium protects smooth muscle against peroxide damage

Cyclopiazonic acid contracts pig coronary artery de-endothelialized rings, and pretreating the rings with hydrogen peroxide (H(2)O(2)) inhibits this contraction (IC(50)=0.097+/-0.013 mM). We used the cyclopiazonic acid contraction to test the novel hypothesis that endothelium can protect underlying smooth muscle against luminal H(2)O(2). We perfused the arteries with Krebs' solution containing 0. 3 or 1 mM H(2)O(2), removing endothelium from the arteries either before or after the perfusion. We then cut rings from them to monitor their contraction to 10 microM cyclopiazonic acid in a H(2)O(2)-free solution. The inhibition of the cyclopiazonic acid contraction by perfusion with H(2)O(2) was significantly less when endothelium was removed after the perfusion than when it was removed before it. The specific activity of catalase in post-nuclear supernatants from freshly isolated endothelium (14.1+/-2.7 micromol/min/mg protein) was 17+/-3-fold greater than in those from smooth muscle (0.83+/-0.22 micromol/min/mg protein). Thus endothelium contained high catalase activity and protected the underlying smooth muscle against luminal peroxide.

SERCA pump isoform expression in endothelium of veins and arteries: every endothelium is not the same

Endothelium from rat aorta expresses sarco/endoplasmic reticulum Ca2+(SERCA) pump gene SERCA3 where as the smooth muscle expresses SERCA2. This has led to the postulate that vascular endothelium expresses SERCA3. To test this postulate, we examined the SERCA2 and SERCA3 mRNA expression in endothelium and smooth muscle dissected from coronary artery, coronary vein, aorta and vena cava of pig. Smooth muscle from all arteries and veins expressed only the SERCA2 mRNA. Endothelium from coronary artery, coronary vein and aorta expressed both SERCA2 and SERCA3 mRNA but the endothelium from vena cava did not express SERCA3 mRNA although it expressed SERCA2. These observations support the postulate that vascular endothelium expresses SERCA3 but the affirmation is equivocal because vena cava endothelium does not express SERCA3.

Sarco/endoplasmic reticulum Ca2+-pump isoform SERCA3a is more resistant to superoxide damage than SERCA2b

Endo/sarcoplasmic reticulum (ER) Ca2+-pumps are important for cell survival and communication but they are inactivated by reactive oxygen species (ROS). We have previously reported that the Ca2+-pump isoform SERCA3a is more resistant than SERCA2b to damage by peroxide. Since peroxide and superoxide differ in their redox potentials, we now report the effects of superoxide on the two Ca2+-pump isoforms. We isolated microsomes from HEK293 cells transiently transfected with SERCA2b or SERCA3a cDNA. We exposed these microsomes to superoxide which was generated using xanthine plus xanthine oxidase and catalase to prevent accumulation of peroxide due to superoxide dismutation. Superoxide damaged the Ca2+-transport activity of both isoforms but SERCA3a was damaged at higher concentrations of superoxide and upon longer periods of exposures than was SERCA2b. Thus the SERCA3a isoform is more resistant than SERCA2b to inactivation by both superoxide and peroxide.

Peroxide sensitivity of endothelin responses in coronary artery smooth muscle: ET(A) vs. ET(B) pathways

Endothelins (ETs) contract de-endothelialized rings from left descending coronary artery via ET(A) or ET(B) receptors. Here we test the hypothesis that the actions of EA(A) and ET(B) receptors are similar in their sensitivities to damage by hydrogen peroxide. In Ca2+-containing Krebs' solution, 100 nM of the ET(B) agonist IRL1620 produced contractions with significantly smaller force (17.6+/-1.7 mN) than 50 nM of the ET(A) + ET(B) agonist ET-1 (73.2+/-4.6 mN) (p < 0.05). In Ca2+-free solutions, the contractions due to both agents were significantly smaller (p < 0.05). Pretreating the tissues with peroxide inhibited the contractions produced by either agent. The IC50 values for peroxide were significantly higher (p < 0.05) using ET-1 (1.0+/-0.3 mM in Ca2+, 1.4+/-0.1 mM in Ca2+-free) than using IRL 1620 (0.32+/-0.08 in Ca2+, 0.25+/-0.01 mM in Ca2+-free). Pretreating microsomes isolated from the artery smooth muscle with up to 10 mM peroxide did not significantly affect 125I-ET-1 binding to ET(A) or ET(B) receptors (p > 0.05). In comparing the peroxide induced inactivation of the various processes in this artery and based on literature, we conclude that the actions of ET(A) may also involve a peroxide resistant Ca2+-independent pathway(s).

ET(B)-mediated contraction differs between left descending coronary artery and its next branch

Pig left descending coronary artery (main artery) and its next branch (branch arteries) differ in many properties. Here we report on the receptor types and the Ca2+ pools utilized for endothelin (ET) contraction in 3 mm long de-endothelialized rings of the main (weight 7.38 +/- 0.38 mg) and the branch (1.07 +/- 0.03 mg) arteries. KCl (60 mM) contracted the main and the branch arteries with force of 41.8 +/- 3.1 and 16.9 +/- 1.0 mN (millinewton), respectively. Force of contraction for all the other agents was normalized taking the KCl value as 100%. We determined the total ET-induced responses using ET-1 and those mediated by ET(B) using IRL1620. In Ca2+-containing solutions, ET-1 contracted the main arteries with pEC50 = 8.2 +/- 0.1 and a maximum force of 98 +/- 5%. The branch arteries also gave similar values of pEC50 (8.4 +/- 0.1) and maximum force (99 +/- 14%). IRL1620 contracted the main and the branch arteries with pEC50 = 7.9 +/- 0.1 but the maximum force was significantly higher in the branch arteries (44 +/- 3%) than in the main (15 +/- 2%). In Ca2+-free solutions, the pEC50 values for ET-1 or IRL-1620 did not change but the maximum force of contraction was diminished considerably in both main and branch arteries. Thus, the left coronary artery and its next branch differ in that the role of ET(B) receptors is greater in the latter.

ATP-dependent silver transport across the basolateral membrane of rainbow trout gills

Silver has been shown to be extremely toxic to freshwater teleosts, acting to inhibit Na(+) uptake at the gills, due to the inactivation of branchial Na(+)/K(+)-ATPase activity. However, the gills are also a route by which silver may enter the fish. Therefore, this study focuses on the mechanism of transport of this nonessential metal across the basolateral membrane of the gill cell, using basolateral membrane vesicles (BLMV) prepared from the gills of freshwater rainbow trout. Uptake of silver by BLMV was via a carrier-mediated process, which was ATP-dependent, reached equilibium over time, and followed Michaelis-Menten kinetics, with maximal transport capacity (V(max)) of 14.3 +/- 5.5 (SE) nmol mg membrane protein(-1) min(-1) and an affinity (K(m)) of 62.6 +/- 43.7 microM, and was inhibited by 100 microM sodium orthovanadate (Na(3)VO(4)). The ionophore monensin (10 microM) released transported silver from the BLMV. Acylphosphate intermediates, of a 104 kDa size, were formed from the BLMV preparations in the presence of ATP plus Ag. These results demonstrate that there is a P-type ATPase present in the basolateral membrane of the gills of rainbow trout that can actively transport silver, a process which will remove this heavy metal from its site of toxic action, the gill.

Granulocytic sarcoma of orbit preceding acute myeloid leukaemia: a case report

A rare case of granulocytic sarcoma of orbit preceding the onset of acute meyloblastic leukaemia is presented. A 7-year-old boy presented with proptosis and no other systemic complaints. The appearance of an enlarged muscle in initial tomographic imaging with a normal peripheral blood picture caused a diagnostic problem. Biopsy suggested a diagnosis of granulocytic sarcoma. Subsequent bone marrow study revealed the diagnosis of acute myeloid leukaemia.

Sarco/endoplasmic reticulum Ca2+ (SERCA)-pumps: link to heart beats and calcium waves

Mobilization of endoplasmic reticulum Ca2+ is pivotal to the ability of a cell to send or respond to stimuli. Ca(2+)-Mg(2+)-ATPases, termed SERCA pumps, sequester Ca2+ into the sarco/endoplasmic reticulum. There are several SERCA protein isoforms encoded by three genes. This paper summarizes the structure, function, tissue and subcellular distribution, and regulation of various SERCA isoforms. Then it attempts to link divergence in the signal transduction processes of cells to the types and levels of SERCA proteins they express and to how the cells regulate their SERCA pump activity. The paper examines possible linkages between SERCA pumps and receptor-activated Ca2+ entry, SERCA isoform localization and Ca(2+)-waves, and the role of SERCA pumps in nuclear Ca2+ in cell proliferation and apoptosis. Then it uses available information on cardiac function and chronic stimulation of the fast-twitch muscle to answer a series of basic questions on the regulation of SERCA activity and expression and their linkage to signal transduction. Finally, it discusses the possibility that neurons exhibit complex Ca(2+)-waves whose interactions have the potential to explain the operational basis of neural networks. A series of unanswered questions emerge based on this synthesis, including the unsettling issue of whether all the isoforms are needed to achieve the divergence in signal transduction or if there is a degree of redundancy in the system.

Effects of peroxide on contractility of coronary artery rings of different sizes

Reactive oxygen species (ROS, free radicals) produced during cardiac ischemia and reperfusion can damage the contractile functions of arteries. The sarcoplasmic reticulum (SR) Ca2+ pump in coronary artery smooth muscle is very sensitive to ROS. Here we show that contractions of de-endothelialized rings from porcine left coronary artery produced by the hormone Angiotensin II and by the SR Ca2+ pump inhibitors cyclopiazonic acid and thapsigargin correlate negatively with the tissue weight. In contrast, the contractions due to membrane depolarization by high KCl correlate positively. Peroxide also produces a small contraction which correlates negatively with the tissue weight. When artery rings are treated with peroxide and washed, their ability to contract with Angiotensin II, cyclopiazonic acid and thapsigargin decreases. Thus, the SR Ca2+ pump may play a more important role in the contractility of the smaller segments of the coronary artery than in the larger segments. These results are consistent with the hypothesis that ROS which damage the SR Ca2+ pump affect the contractile function of the distal segments more adversely than of the proximal segments.