Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “REST”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,243 records · Page 69Linked to original sources
PubMed1995

Nitric oxide release from resting human platelets.

In this study, we have investigated the release of nitric oxide from resting human platelets. Nitric oxide was detected and quantitated by either measuring the conversion of oxy-hemoglobin to met-hemoglobin or generation of nitrite and nitrate by the cells. Nitric oxide was released from both intact resting platelets and platelets activated by collagen. Nitric oxide release was proportional to platelet concentration, and was equivalent to approximately 4.5 +/- 0.6 pmol (or 2.8 +/- 0.3 pmol in the presence of prostaglandin I2) and 11.2 +/- 1.3 pmol nitric oxide released per minute per 10(8) cells at 37 degrees C for resting platelets and platelets activated by collagen, respectively. The generation of nitric oxide by resting platelets was linear with respect to time over a two hour period, while the release of nitric oxide from platelets following activation was transient and was linear for only the first 10 min, after which it slowed to completion at approximately 30 min. The release of nitric oxide was it slowed to completion at approximately 30 min. The release of nitric oxide was stimulated by L-arginine, but was inhibited by L-nitro-arginine methyl ester (L-NAME). The inhibitory effect of L-NAME could be reversed by addition of L-arginine. The release of nitric oxide from platelets was also partially inhibited by prostaglandin I2, prostaglandin E1, aspirin and EDTA. The amount of nitric oxide released from resting platelets compared with that released from endothelial cells suggests that platelet-derived nitric oxide may play a significant role in the maintenance of vascular tone and blood flow.

Blood Platelets↗
PubMed1982

Regulation of nucleotide and pentose synthesis in resting and stimulated 3T6 fibroblasts.

A two-step procedure has been used to follow the activation of one metabolic system involved in the return of cells to a proliferative state after resting in a Go state as a result of serum limitation. One feature of the resting state is a limited capacity to synthesize nucleotides. The limitation apparently is in the rate of synthesis of 5-phosphoribosylpyrophosphate from glucose and indirectly in the capacity of the resting cells to turn over the triphosphopyridine nucleotide pair, NADPH:NADP+. A reaction utilizing NADPH is apparently greatly diminished in resting cells and is substantially increased by only brief contact of cells with the hormonal elements in dialyzed calf serum. Insulin together with platelet-derived growth factor can substitute for calf serum. Aside from stimulating the turnover of the pyridine nucleotide coenzyme pair, serum also stimulates the utilization and reformation of ATP, principally from AMP. Among the NADPH-linked reactions that have been examined for their physiological significance in the initiation of growth stimulation are two steps in the conversion of glutamate to proline in the cytoplasm. Pyrroline 5-carboxylate, an intermediate in this metabolic pathway, has been shown to stimulate PRPP synthesis when added to cultures of resting 3T6 cells. Proline, the product of the reduction of this 5-membered heterocycle is also a stimulant of PRPP synthesis. In addition, dehydroascorbic acid is a potent stimulant of PRPP synthesis. As a working hypothesis, we are exploring the role of a series of reactions that form a pyrroline 5-carboxylate/proline cycle operating between the cytoplasm and mitochondria. The net result is the oxidation of NADPH by molecular oxygen to yield NADP+ and water. The NADP+ is then used in the hexose monophosphate pathway for the conversion of glucose to PRPP. We wish to determine whether dehydroascorbate is operating in this cycle as an oxidant of proline in the mitochondria or whether it participates in some other reaction in the cell that redistributes the ratio of NADPH to NADP.

Cell Division↗
PubMed1975

The messenger RNA sequences in growing and resting mouse fibroblasts.

The sequences present in messenger RNA in resting and growing 3T6 cells have been examined. First, the abundance and complexity classes of mRNA in growing 3T6 were compared to those in other established cell lines. The overall complexities measured for mRNA from HeLa cells and the three mouse fibroblast lines, 3T6, SV-PY-3T3, and L, are qualitatively similar and correspond to approximately 10,000 sequences. The relative amount of the two major abundance classes and their complexities appear identical in the three mouse fibroblast lines despite their different histories. HeLa cell mRNA is significantly different both in the amount and the complexity of the two major classes. The complexity of the two mRNA classes appears the same in resting and growing 3T6, although there is a small difference in relative amounts. Cross hybridizing cDNA and mRNA from resting and growing cells shows that the majority of mRNA sequences are the same in the two states. However, cross hybridization after the common sequences are removed shows that about 3% of the mRNA in resting cells is not present in the growing state, while the opposite cross shows 3% of the mRNA in growing cells is not present in resting cells. These differences may result from alterations in gene expression which are related to the growth state of the cell.

Base Sequence↗
PubMed1975

Changes in RNA in relation to growth of the fibroblast. III. Posttranscriptional regulation of mRNA formation in resting and growing cells.

The proportion of hnRNA processed into cytoplasmic mRNA in resting and growing 3T3 and 3T6 cells has been investigated by measuring the efficiency of transfer of nuclear poly(A) to the cytoplasm. When nuclear poly(A) is either labeled continuously with precursor or pulse labeled and then chased with cordycepin, growing cells transfer approximately twice as much of the poly(A) from the nucleus to the cytoplasm as do resting cells. When cells undergo a serum-induced transition from the resting to growing state, the efficiency of poly(A) transfer is increased to that characteristic of growing cells by 3 hr after the addition of the serum. On the other hand, the proportion of hnRNA which is polyadenylated and the total nuclear poly(A) content are the same in resting and growing cells. It appears that the principal means by which the cell regulates its poly(A)+ mRNA content in the growing and resting states is by regulating the efficiency which nuclear poly(A)+ RNA is converted to cytoplasmic mRNA.

Adenine↗
PubMed1993

Transformation of rifamycin B with growing and resting cells of Curvularia lunata.

Growing and resting cell systems of Curvularia lunata were used for the transformation of rifamycin B to rifamycin S. In the case of growing cells, rifamycin B was added at the time of inoculation and at the different phases of growth. Interestingly, it was found that C. lunata could grow in the presence of rifamycin B and could convert rifamycin B to rifamycin S. Growing cells 24 and 48 h of age were capable of transforming rifamycin B. Resting cells, cultivated at the exponential or early stationary phase, were found to be very active, and the resting cells of different ages were repeatedly used for the transformation reaction. Growing cells of 72 and 96 h were not capable of transforming rifamycin B, whereas resting cells of similar ages were very active. Due to the adsorption of rifamycins by the growing and resting cells of C. lunata, the stoichiometric yield of rifamycin S was not obtained.

Biotransformation↗
PubMed1994

Functional role of charybdotoxin-sensitive K+ channels in the resting state of dog basilar artery.

To determine the possible role of Ca(2+)-activated K+ (KCa) channels in the regulation of resting tone of cerebral arteries, the effect of agents which interact with these channels on tension and 86Rb efflux was examined in endothelium-denuded strips of dog basilar artery, and data were compared with findings in the mesenteric artery. The basilar artery maintained a myogenic tone; that is, the resting tone decreased when nifedipine was added. The addition of charybdotoxin, a blocker of large conductance KCa channels, caused a concentration-dependent contraction in the basilar artery but not in the mesenteric artery. In strips preloaded with 86Rb, the basal 86Rb efflux rate constant was significantly greater in the basilar artery than in the mesenteric artery. Nifedipine decreased the basal 86Rb efflux rate constant only in the basilar artery. The basal 45Ca influx in the resting state of the basilar artery was significantly increased when compared with the mesenteric artery and this increase in the basilar artery was reduced by nifedipine. The results suggest that the charybdotoxin-sensitive KCa channels regulate the myogenic tone in the resting state of the basilar artery. The activation of KCa channels in the basilar artery appears to be secondary to the increased transmembrane Ca2+ influx probably via the activation of L-type voltage-dependent Ca2+ channels in the resting state of this artery.

Animals↗
PubMed1988

Cardiac function at rest and during exercise in early and late alcohol intoxication.

Seven healthy men, aged 21 to 30 years, were investigated by radionuclide cardiography at rest and during submaximal exercise at heavy (early) and during declining (late) alcohol intoxication. Control studies, in which alcohol was substituted by an isocaloric, isovolumic drink, were performed on a different day. The left ventricular ejection fraction at rest decreased from 59 to 56% during early intoxication (serum ethanol 35 +/- 6 mmol/l), whereas no change was observed in the ejection fraction during exercise. No significant change was recorded in stroke volume after alcohol consumption as opposed to a small increase after ingestion of the caloric drink. Plasma noradrenaline concentrations were elevated during exercise and early intoxication. During late intoxication (serum ethanol 21 +/- 5 mmol/l) the left ventricular ejection fraction at rest was increased by 7% compared with the baseline value. At rest the heart rate was increased from 68 +/- 7 to 84 +/- 15 beats/min, whereas cardiac output had reverted to the baseline value. Plasma noradrenaline at late intoxication was increased both at rest and during exercise compared with the baseline values. Apart from tachycardia and a reduction in left ventricular volumes during late intoxication no alcohol induced hemodynamic changes occurred during exercise.

Adult↗
PubMed1994

Resting membrane potentials and excitability at different regions of rat dorsal root ganglion neurons in culture.

To study the role of electrical membrane processes in neuronal regeneration and growth, resting membrane potentials and action potentials of sensory (dorsal root ganglion) neurons growing in culture were measured at the soma, neurite and growth cone using the whole-cell patch-clamp technique. Our results show that resting membrane potentials measured at the soma (-56.8 +/- 8.8 mV), neurite varicosity (-55.8 +/- 5.2 mV) and growth cone (-57.2 +/- 4.1 mV) of growing neurons were not statistically different. The membrane resistance measured around the resting membrane potential at the neurite varicosity (160 +/- 70 M omega) was smaller than those at the soma (687 +/- 540 M omega) and growth cone (922 +/- 825 M omega). The resting membrane potential measured at the soma using a perforated patch (-60.3 +/- 4.4 mV) was not different from that measured in the normal whole cell. In both configurations, isotonic KCl (140 mM) depolarized the membrane potential to above 0 mV. The K+ channel blockers quinine, Cs+, 4-aminopyridine and tetraethylammonium depolarized the membrane potential by 10-40 mV, while Na(+)-free extracellular solution hyperpolarized it by about 10 mV. Extracellularly applied ouabain, intracellular Na(+)-free or low Cl(-)-containing solutions did not affect the resting membrane potential. Similar results were obtained for growth cones. Action potentials could be evoked by current pulses in 81% of somata and in all growth cones, but not in neurite varicosities. Current-induced repetitive firing was found in 19% of somata and in 65% of growth cones.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1992

Relation between left ventricular function at rest and with exercise and silent myocardial ischemia.

The prognostic value of radionuclide measures of left ventricular function at rest and exercise is well established. Some studies have suggested that the frequency and duration of silent ischemia during ambulatory monitoring provide similar prognostic information; however, studies comparing these two techniques have not been performed. This study examines the relation between left ventricular function at rest and exercise-induced ischemia assessed by radionuclide ventriculography with myocardial ischemia during ambulatory electrocardiographic (ECG) monitoring. Of the 155 patients with coronary artery disease studied, 88% had left ventricular dysfunction with exercise, defined as failure of the ejection fraction to increase by greater than 4% with exercise, and 33% of patients had left ventricular dysfunction at rest (ejection fraction less than 45%); 52% had transient episodes of ST segment depression during 48-h ambulatory ECG monitoring. Exercise-induced left ventricular dysfunction during radionuclide ventriculography was extremely sensitive (94%) in detecting patients with ischemic episodes during ambulatory ECG monitoring; however, only 55% of patients with exercise-induced left ventricular dysfunction had ST segment depression during ambulatory monitoring. Moreover, patients with left ventricular dysfunction at rest had a lower prevalence of transient episodes of ST segment depression (31%) than did patients with normal left ventricular function at rest (62%) (p = 0.008). The relation between prognostically important variables during exercise radionuclide ventriculography and the number and duration of transient episodes of ST depression was examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

On the resting potential of isolated frog sympathetic neurons.

One of the oldest questions of electrophysiology, the origin of the resting potential, has yet to be answered satisfactorily for most cells. Isolated frog sympathetic neurons, studied with whole-cell recording, generally have resting potentials of approximately -75 mV with an input resistance of approximately 300 M omega. These properties are not expected from the M-type K+ current (IM) or from other ionic currents previously described in these cells. In the -60 to -110 M mV voltage region, at least three currents are present: an inwardly rectifying current (IQ), a resting current with little voltage sensitivity carried at least in part by K+, and a (Na+,K+)ATPase pump current. The resting K+ current, not IM or IQ is the primary ionic current near the resting potential under these conditions. The electrogenic pump contributes an additional approximately 10 mV of hyperpolarization.

Animals↗
PubMed1988

Differential expression of phenotype by resting zone and growth region costochondral chondrocytes in vitro.

This study establishes an in vitro model for examining endochondral cartilage cell metabolism. Chondrocytes derived from the resting cell zone and adjacent growth zone of rat costochondral cartilage were compared for retention of phenotype in culture. At third passage confluence, two cell populations differ morphologically and biochemically. Resting zone cells are fibroblast-like, with smooth cell membranes and little rough endoplasmic reticulum. Growth zone cells are more polygonal, smaller in diameter, with numerous cytoplasmic extensions of the plasma membranes and abundant rough endoplasmic reticulum. Both cell populations produce matrix vesicles that are comparable morphologically to matrix vesicles isolated enzymatically from epiphyseal cartilage. While membrane vesicles are released into the media by cells derived from the resting zone as well as from the growth cartilage, alkaline phosphatase activity is enriched in media vesicles produced by growth cartilage cells. Alkaline phosphatase enriched vesicles appear to be preferentially incorporated into the extracellular matrix. Both the plasma membrane marker enzyme activity and the membrane phospholipid composition are differentially expressed in matrix vesicles and plasma membranes and are cell specific. Matrix vesicles produced by resting zone cells are enriched in alkaline phosphatase, 5'-nucleotidase, ouabain sensitive Na+/K+ ATPase and cardiolipin when compared to the cell membrane. In addition, the plasma membranes of these cells contain more phosphatidylcholine plus sphingomyelin than do growth cartilage plasma membranes. Resting zone cell matrix vesicles have less phosphatidylethanolamine than do vesicles from growth cartilage cultures. Matrix vesicles produced by growth cartilage cells contain one proteolipid at 43,000 Mr which comigrates with plasma membrane proteolipid and an additional proteolipid at approximately 3,000 Mr. These data indicate that both cells retain differential expression of phenotype in culture and that one expression of this phenotype is production of specific extracellular matrix vesicles.

Animals↗
PubMed2005

In resting COS1 cells a dominant negative approach shows that specific, anchored PDE4 cAMP phosphodiesterase isoforms gate the activation, by basal cyclic AMP production, of AKAP-tethered protein kinase A type II located in the centrosomal region.

We employ a novel, dominant negative approach to identify a key role for certain tethered cyclic AMP specific phosphodiesterase-4 (PDE4) isoforms in regulating cyclic AMP dependent protein kinase A (PKA) sub-populations in resting COS1 cells. A fraction of PKA is clearly active in resting COS1 cells and this activity increases when cells are treated with the selective PDE4 inhibitor, rolipram. Point mutation of a critical, conserved aspartate residue in the catalytic site of long PDE4A4, PDE4B1, PDE4C2 and PDE4D3 isoforms renders them catalytically inactive. Overexpressed in resting COS1 cells, catalytically inactive forms of PDE4C2 and PDE4D3, but not PDE4A4 and PDE4B1, are constitutively PKA phosphorylated while overexpressed active versions of all these isoforms are not. Inactive and active versions of all these isoforms are PKA phosphorylated in cells where protein kinase A is maximally activated with forskolin and IBMX. By contrast, rolipram challenge of COS1 cells selectively triggers the PKA phosphorylation of recombinant, active PDE4D3 and PDE4C2 but not recombinant, active PDE4A4 and PDE4B1. Purified, recombinant PDE4D3 and PDE4A4 show a similar dose-dependency for in vitro phosphorylation by PKA. Disruption of the tethering of PKA type-II to PKA anchor proteins (AKAPs), achieved using the peptide Ht31, prevents inactive forms of PDE4C2 and PDE4D3 being constitutively PKA phosphorylated in resting cells as does siRNA-mediated knockdown of PKA-RII, but not PKA-RI. PDE4C2 and PDE4D3 co-immunoprecipitate from COS1 cell lysates with 250 kDa and 450 kDa AKAPs that tether PKA type-II and not PKA type-I. PKA type-II co-localises with AKAP450 in the centrosomal region of COS1 cells. The perinuclear distribution of recombinant, inactive PDE4D3, but not inactive PDE4A4, overlaps with AKAP450 and PKA type-II. The distribution of PKA phosphorylated inactive PDE4D3 also overlaps with that of AKAP450 in the centrosomal region of COS1 cells. We propose that a novel role for PDE4D3 and PDE4C2 is to gate the activation of AKAP450-tethered PKA type-II localised in the perinuclear region under conditions of basal cAMP generation in resting cells.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2005

Clinical, resting echo and dipyridamole stress echocardiography findings for the screening of renal transplant candidates.

BACKGROUND: Preoperative screening for coronary artery disease is recommended in high-risk renal transplant candidates. Aim of this study was to prospectively assess the value of a comprehensive risk stratification strategy including clinical, resting echo, and dipyridamole stress echo findings before renal transplantation. METHODS: The study group consisted of 71 renal transplant candidates (47 men; age 54+/-11 years) fulfilling one or more of the following high-risk clinical criteria: history of coronary artery disease, wall motion abnormalities at resting echo, dialysis dependency lasting >5 years, presence of 2 or more risk factors. Clinical history, resting echo, and dipyridamole stress echo (up to 0.84 mg over 10 min + atropine up to 1 mg) were obtained in all subjects. RESULTS: Mean number of risk factors was 2.5+/-1.0. Known coronary artery disease and diabetes were present, respectively, in 2 (3%) and 11 (15%) persons. No patient had left ventricular ejection fraction <45%. Left ventricular hypertrophy was found in 53 (74%) cases. Stress echo showed 100% safety and 97% overall feasibility. Inducible ischemia (new wall motion abnormalities) was detected in 3 (4%) subjects. During follow-up (36+/-12 months), 8 (11%) cardiac events occurred: 2 deaths, 2 myocardial infarctions, 3 coronary interventions, and 1 pulmonary edema. The perioperative period and subsequent follow-up (22+/-12 months) was uneventful among 32 patients who received renal transplantation. Four-year event-free survival was 92% in those without ischemia; it was 96% in the non-diabetic population. Diabetes (HR=4.78), age (HR=1.14), and left ventricular mass index (HR=1.02) were independent prognostic indicators among clinical and resting echo variables. The global chi-square of the statistical model was 18.8; it increased to 27.3 (+45%) after the addition of stress echo result. CONCLUSIONS: Renal transplant candidates can undergo effective stratification of risk by combining clinical, resting echo and dipyridamole stress echo findings.

Adult↗
PubMed2006

Regional heterogeneity of resting perfusion in hypertrophic cardiomyopathy is related to delayed contrast enhancement but not to systolic function: a PET and MRI study.

BACKGROUND: Regional differences in resting myocardial blood flow (MBF) have been observed in patients with hypertrophic cardiomyopathy (HCM), but their determinants are currently unknown. This study verifies whether MBF at rest in HCM is related to delayed contrast enhancement (DCE) or regional systolic function (or both) as determined by magnetic resonance imaging. METHODS AND RESULTS: Fourteen patients with HCM were studied. MBF was measured with positron emission tomography by use of oxygen 15-labeled water. DCE and tissue tagging, to calculate end-systolic circumferential shortening (Ecc), were obtained with magnetic resonance imaging. The mean resting MBF was 0.78 +/- 0.19 mL x min(-1) x mL(-1), and there was a trend toward reduced MBF in the septum (0.72 +/- 0.11 mL x min(-1) x mL(-1)) compared with that in the lateral wall (0.84 +/- 0.29 mL x min(-1) x mL(-1)) (P = .092). The distribution patterns of DCE and Ecc were both heterogeneous, displaying significantly increased enhancement and impaired regional systolic function in the hypertrophic septum compared with the lateral wall (both P < .001). Resting MBF was inversely related to the extent of DCE (r = -0.30, P < .001), whereas MBF was not significantly related to Ecc (r = -0.15, P = .072). CONCLUSIONS: Regional heterogeneity of resting perfusion in HCM is related to the extent of DCE but not to regional systolic function.

Adult↗
PubMed2004

Influence of resting tension on protease-activated receptor-mediated relaxation in guinea-pig tracheas.

We investigate the role of resting tension on thrombin (THR) induced relaxation of guinea-pig tracheas precontracted with acetylcholine (ACh). Isometric contractions of isolated guinea-pig tracheas were recorded at 4 and 6 g resting tension; and ACh dose-response curves were performed. THR relaxed ACh-precontracted tracheas and this effect was mimicked by the type 2 protease activating receptor agonist peptide (PAR-2 AP) and trypsin. The relaxant effect of 3 U ml(-1) THR and 100 nmol ml(-1) PAR-2 AP was prevented at 4 g by preincubation with the nitric oxide synthase (NOS) inhibitor l-NAME and at 6g resting tension by ibuprofen and diclofenac. However, adenosine trisphospahate (ATP) relaxation was totally prevented by cyclooxygenase (COX) inhibitors but not by NOS inhibitors at both resting tensions. Resting tension influenced the effect of PGE2 on contractile tone of isolated guinea-pig tracheas, the maximal relaxation being -11.1+/-2.97 and -2.0+/-0.4 6 mg mg(-1) tissue wet weight at 6 and 4 g, respectively. Moreover, 30 nmol ml(-1) PGE2 can relax ACh-precontracted tracheas, being the effect up to 91 and 30% at 6 and 4 g, respectively. These data demonstrate that trachea responsiveness is highly dependent on the smooth muscle length, revealing new aspects of stretch-activated receptors that can influence trachea responsiveness in vivo.

Acetylcholine↗
PubMed2004

Antiphospholipid antibodies bind to activated but not resting endothelial cells: is an independent triggering event required to induce antiphospholipid antibody-mediated disease?

INTRODUCTION: Antiphospholipid antibodies (aPL) cause thrombotic disease and recurrent pregnancy loss. Despite their name it is now clear that the antigen for most antiphospholipid antibodies is the phospholipid-binding protein beta(2) glycoprotein I (beta(2)GPI). However, beta(2) glycoprotein I is only antigenic for antiphospholipid antibodies when the protein is immobilised on a suitable surface such as phosphatidyl serine. It has been suggested that antiphospholipid antibodies bind to beta(2) glycoprotein I on the surface of resting endothelial cells and this in turn leads to endothelial activation and the initiation of thrombosis. However, as phosphatidyl serine is absent from resting endothelial cell membranes, we questioned this hypothesis. MATERIALS AND METHODS: The ability of human antiphospholipid antibody-containing sera and monoclonal antiphospholipid antibodies to interact with endothelial cells was examined using cell-based ELISAs employing human umbilical vein endothelial cells (HUVECs) as the antigen. The expression of adhesion molecules in response to treatment with antiphospholipid antibodies was also measured by a cell-based ELISA. Activation of NF kappa beta was examined using electrophoretic mobility shift assays (EMSAs). RESULTS: Neither monoclonal antiphospholipid antibodies nor human sera containing antiphospholipid antibodies bound to resting endothelial cells. In contrast, one monoclonal antiphospholipid antibody did bind to both activated and apoptotic endothelial cells. CONCLUSIONS: Antiphospholipid antibodies do not bind to resting endothelial cells nor do antiphospholipid antibodies activate resting endothelial cells. Rather, an independent triggering event is required to activate endothelial cells and subsequently some antiphospholipid antibodies may then bind to the activated endothelial cells and initiate a thrombogenic process.

Antibodies, Antiphospholipid↗
PubMed2006

Phenotypic and genotypic heterogeneity in Gaucher disease type 1: a comparison between Brazil and the rest of the world.

Type 1 Gaucher disease, the most common lysosomal storage disorder, results from deficiency of glucocerebrosidase causing pathologic accumulation of glucocerebroside. The disease is characterized by marked variation in age of onset and degree of anemia, thrombocytopenia, hepatosplenomegaly, and skeletal disease. Most published data on Gaucher disease come from populations with large proportions of Ashkenazi-Jewish patients, who tend to have less severe disease. We compared selected demographic, clinical, and genetic parameters for Brazilian (N = 221) and rest-of-world (N = 1477) type 1 Gaucher disease patients entered into the ICGG Gaucher Registry since 1991. We also compared Brazilian patients to non-Ashkenazi rest-of-world patients (N = 692) to determine if differences were the result of fewer Brazilian Ashkenazi-Jewish patients (0.5% vs 45.0%). The Brazilian cohort differed significantly (p < 0.05) from the rest-of-world and rest-of-world non-Ashkenazi cohort, respectively, in the following measures: higher proportion of females (59.7% vs 50.4% and 49.7%), lower mean age at diagnosis (17.1 vs 24.1 and 18.8), and higher proportions of patients with anemia (55.5% vs 29.9% and 35.7%), bone pain (57.7% vs 33.7% and 35%), bone crises (16.1% vs 6.5% and 7.4%), and lytic lesions (17.0% vs 7.6% and 7.4%). The most common genotype in Brazil was N370S/L444P (c1448T-->C/c1226A-->C) (46.8% versus 16.3% and 25.7%). These data highlight the genetic and phenotypic heterogeneity among geographic populations of type 1 Gaucher patients and suggest that as a group, Brazilian patients may have a more aggressive form of the disease than rest-of-world patients. The findings also emphasize the need for caution in making generalizations about Gaucher disease across demographic groups.

Adolescent↗
PubMed1996

Reciprocating supraventricular tachycardia in children: low rate at rest as a major factor related to propensity to syncope during exercise.

Reciprocating supraventricular tachycardia may have several clinical presentations, with symptoms often more severe during exercise or emotional stress. This study shows by using transesophageal atrial pacing, the factors related to syncope during exercise. Between May 1989 and June 1994, transesophageal atrial pacing was performed at rest and during exercise in 75 children aged > 6 years with suspected or documented episodes of paroxysmal supraventricular tachycardia. Reciprocating supraventricular tachycardia could be induced both at rest and during exercise in 22 patients (8 girls, 14 boys; mean age 10.6 +/- 2.7 years, range 7 to 15 years) with ventriculoatrial interval < 70 msec in 11 patients and > 70 msec in 11. At rest, all patients had palpitations caused by the induction of tachycardia. After conversion to sinus rhythm, when tachycardia was induced during exercise, symptoms did not change in 14 patients (group A), whereas symptoms worsened (presyncope) in eight (group B). The statistical analysis showed a significant difference of mean reciprocating supraventricular tachycardia rate at rest between the two groups (group A, 211 +/- 23 beats/min; group B, 173 +/- 33 beats/min; p = 0.0057) and reciprocating supraventricular tachycardia rate variation from rest to exercise (group A, 62 +/- 18 beats/min; group B, 105 +/- 24 beats/min; p = 0.0001). These data suggest that children with low tachycardia rate during normal activities may have syncope more frequently, independently of the tachycardia rate during exercise or emotional stress.

Adolescent↗