Search results for "Calcium"
showing 10 items of 1740 documents
Tetrodotoxin slightly shortens action potential duration in ventricular but not in atrial heart muscle.
1988
Tetrodotoxin (TTX), at concentrations significantly decreasing maximal upstroke velocity (dV/dtmax) of the action potential, exerted variable effects on action potential duration (APD) in different myocardial preparations. APD was virtually unchanged by tetrodotoxin in the guinea pig atrium, but slightly shortened in the guinea pig ventricle at maximally effective concentrations. In the human ventricle, both dV/dtmax and APD were reduced in the same concentration range of TTX. These results suggest that a TTX-sensitive sodium current significantly contributes to the repolarization phase of the action potential in ventricular but not in atrial heart muscle.
Pharmacological Therapy in Children with Atrial Fibrillation and Atrial Flutter
2008
Heart rhythm disorders in children are not different, on electrocardiographic trace, from heart rhythm disorders in adults with the exception of incidence which is different according to the age. Paticularly, atrial flutter (FlA) and fibrillation (FA) are very uncommon arrhythmias in the general pediatric population. Generally atrial fibrillation and atrial flutter, in our experience, is a temporary heart rhythm disturbance connected to specifical and resovable reasons with the exception of Fontains surgical correction of congenital heart diseases or cardiopathies with dilatation of both atria. Presenting symptoms, symptom history (e.g., frequency, duration, and severity), risk assessment, …
Effekt von Calcium und Magnesium auf die Parathormonfreisetzung aus humanem Parathyreoidea-Gewebe in vitro
1982
The effects of calcium and magnesium on parathyroid hormone release from eight adenomas causing primary hyperparathyroidism and six hyperplastic glands causing hypercalcemic secondary hyperparathyroidism were investigated in vitro using single cell suspensions from the respective tissue. We observed suppression of parathyroid hormone release with increasing concentrations of either cation. The quantitative hormone secretions of both adenomatous and hyperplastic glands was identical.
Inhibition of ovarian steroidogenesis by cyclic-GMP in a fly
2003
1479-6805 0022-0795; Previous investigations in the female blowfly Phormia regina have shown that 3-isobutyl-1-methylxanthine (IBMX), a broad spectrum inhibitor of phosphodiesterases (PDEs), fails to mimic the steroidogenic effects of cAMP on ovaries, although it efficiently increases the concentrations of this second messenger. In this study, experiments carried out to clear up this contradiction demonstrated that IBMX, besides its effect on cAMP, also increased cGMP concentrations in blowfly ovary and that these two cyclic nucleotides controlled ovarian steroidogenesis antagonistically. In particular, a selective inhibitor of cGMP-specific PDEs, unlike IBMX, had a very strong negative eff…
Hypercalciuria and kidney calcifications in terminal 4q deletion syndrome: Further evidence for a putative gene on 4q
2003
We report a newborn girl with a de novo terminal 4q deletion (q31.3 → qter) and a characteristic phenotype of minor facial anomalies, cleft palate, congenital heart defect, abnormalities of hands and feet, and postnatal onset of growth deficiency. Laboratory studies showed excessive urinary calcium excretion on standard milk formula and on oral calcium load. Blood measurements of parathyroid hormone, calcitonin, bicarbonate, calcium, phosphorus, magnesium, sodium, chlorine, potassium, and urinary measurements of phosphorus, magnesium, sodium, chlorine, potassium were normal for age. At 2 months of life, ultrasonography showed kidney calcifications. Clinical and laboratory data support the d…
Surgical sphincter saving approach and topical nifedipine for chronic anal fissure with hypertonic internal anal sphincter
2020
PURPOSE The role of augmented internal anal sphincter (IAS) tone in the genesis of posterior chronic anal fissure (CAPF) is still unknown. Lateral internal sphincterotomy is the most employed surgical procedure, nevertheless it is burdened by high risk post-operative anal incontinence. The aim of our study is to evaluate results of sphincter saving procedure with post-operative pharmacological sphincterotomy for patients affected by CAPF with IAS hypertonia. Methods: We enrolled 30 patients, undergone fissurectomy and anoplasty with V-Y cutaneous flap advancement; all patients received topical administration of nifedipine 0.3% and lidocaine 1.5% ointment-based therapy before and for 15 days…
The phototransduction cascade in the isolated chick pineal gland revisited.
2003
It is well established that the isolated chick pineal gland is directly light sensitive and that melatonin synthesis of the gland can be inhibited by exposing the gland to light during scotophase. Since not all the steps of the phototransduction cascade have been clarified to the same extent as in the retina, we have treated isolated chick pineal glands with 90 min of light during scotophase and with drugs that affect key-components of vertebrate phototransduction, i.e., cyclic guanosine monophosphate (cGMP) phosphodiesterase 6 (PDE6), cGMP levels and cGMP-gated calcium channels. The endpoint measured was the activity of the rate-limiting enzyme of melatonin synthesis, arylalkylamine N-acet…
Does Serum 25-Hydroxyvitamin D Influence Muscle Development during Puberty in Girls? - A 7-Year Longitudinal Study
2013
Vitamin D is well known for its regulatory role in calcium and phosphate homeostasis, but its role in muscle mass and strength during growth remains inconclusive. We explored the association of serum 25-hydroxyvitamin D (25(OH)D) with muscle development in girls from 11 to 18-years old. Whole body lean tissue mass (LMWB), appendicular lean mass (aLM), muscle cross-sectional area at the lower leg (mCSA), maximal voluntary contraction of elbow flexors (MVC elbow) and knee extensors (MVC knee) were assessed in 217 girls aged 10-13 years (at baseline), 215 in 2-year and 226 in 7.5-year follow-up. Serum concentration of 25(OH)D and intact parathyroid hormone (PTH) were analyzed retrospectively a…
Magnesium metabolism in hypertension and type 2 diabetes mellitus.
2007
The increasing evidence for the clinical relevance of altered magnesium metabolism to states of altered insulin resistance confirms the role of magnesium deficit as a possible underlying common mechanism of the "insulin resistance" of hypertension and altered glucose tolerance. The pioneer work of Lawrence M. Resnick and his group using the cellular ion-based approach that we are only partially presenting here has consistently contributed to the progress of the field, demonstrating (a) the critical importance of magnesium metabolism in regulating insulin sensitivity as well as vascular tone, and blood-pressure homeostasis; (b) that magnesium deficiency, defined on the basis of intracellular…
Effects of calcium, dairy product, and vitamin D supplementation on bone mass accrual and body composition in 10-12-y-old girls: a 2-y randomized tri…
2005
Little is known about the relative effectiveness of calcium supplementation from food or pills with or without vitamin D supplementation for bone mass accrual during the rapid growth period.The purpose was to examine the effects of both food-based and pill supplements of calcium and vitamin D on bone mass and body composition in girls aged 10-12 y.This placebo-controlled intervention trial randomly assigned 195 healthy girls at Tanner stage I-II, aged 10-12 y, with dietary calcium intakes900 mg/d to 1 of 4 groups: calcium (1000 mg) + vitamin D3 (200 IU), calcium (1000 mg), cheese (1000 mg calcium), and placebo. Primary outcomes were bone indexes of the hip, spine, and whole body by dual-ene…