Correlation between 25-hydroxyvitamin D levels and latitude in Brazilian postmenopausal women: from the Arzoxifene Generations Trial

SUMMARY

We investigated vitamin D status in Brazilian cities located at different latitudes. Insufficiency (<50 nmol/L) was common (17 %), even in those living in a tropical climate. Vitamin D insufficiency increased as a function of latitude. Mean 25-hydroxyvitamin D (25(OH)D) levels in each site and latitude correlation were very high (r = -0.88; p=0.02). [corrected].

INTRODUCTION

Inadequate vitamin D, determined by low levels of 25(OH)D, has become very common despite the availability of sunlight at some latitudes. National data from a country that spans a wide range of latitudes would help to determine to what extent latitude or other factors are responsible for vitamin D deficiency. We investigated vitamin D status in cities located at different latitudes in Brazil, a large continental country.

METHODS

The source is the Brazilian database from the Generations Trial (1,933 osteopenic or osteoporotic postmenopausal women (60 to 85 years old) with 25(OH)D measurements). 25(OH)D below 25 nmol/L (10 ng/mL) was an exclusion criterion. Baseline values were between fall and winter. The sites included Recife, Salvador, Rio de Janeiro, São Paulo, Curitiba, and Porto Alegre. Mean and standard deviation of 25(OH)D, age, spine and femoral neck T-score, calcium, creatinine, and alkaline phosphatase were calculated for each city. Pearson correlation was used for 25(OH)D and latitude.

RESULTS

Insufficiency (<50 or <20 ng/mL) was common (329 subjects, 17 %). Vitamin D insufficiency increased as a function of latitude, reaching 24.5 % in the southernmost city, Porto Alegre. The correlation between mean 25(OH)D levels in each site and latitude was very high (r = -0.88, p < 0.0001).

CONCLUSION

There is a high percentage of individuals with vitamin D insufficiency in Brazil, even in cities near the equator, and this percentage progressively increases with more southern latitudes.

Unusual causes of abdominal pain: sickle cell anemia

Sickle cell disease is characterized by chronic hemolytic anemia and vaso-occlusive painful crises. The vascular occlusion in sickle cell disease is a complex process and accounts for the majority of the clinical manifestation of the disease. Abdominal pain is an important component of vaso-occlusive painful crises. It often represents a substantial diagnostic challenge in this population of patients. These episodes are often attributed to micro-vessel occlusion and infarcts of mesentery and abdominal viscera. Abdominal pain due to sickle cell vaso-occlusive crisis is often indistinguishable from an acute intra-abdominal disease process such as acute cholecystitis, acute pancreatitis, hepatic infarction, ischemic colitis and acute appendicitis. In the majority of cases, however, no specific cause is identified and spontaneous resolution occurs. This chapter will focus on etiologies, pathophysiology and management of abdominal pain in patients with sickle cell disease.

Echocardiographic abnormalities in sickle cell disease

Echocardiographic abnormalities in patients with sickle cell disease (SCD) were determined, and pulmonary arterial systolic pressure (PASP) was estimated. Clinical data and echocardiograms of 38 adult hospitalized patients with SCD at two tertiary care hospitals were reviewed. Fisher's exact test was performed to determine correlation between pulmonary hypertension and various clinical variables. Pulmonary hypertension was the most common abnormality identified in 22 (58%) patients. The estimated mean PASP was 37.5 +/- 10.9 mmHg. Older age and prior history of acute chest syndrome were significantly correlated with an increased prevalence of pulmonary hypertension (P < 0.05). Patients with hemoglobin levels <8 g/dL had PASP 43.2 +/- 0.5 compared to a mean PASP of 33.3 +/- 6.0 in patients with hemoglobin > or =8 g/dL (P = 0.01). Eight (21%) patients had evidence of a hyperdynamic left ventricle. Left heart abnormalities included dilated atrium in 14 (37%), dilated ventricle in 5 (13%), ventricle hypertrophy in 5 (13%), and ventricle dysfunction in 3 (9%) patients. Right heart abnormalities included dilated atrium in 9 (24%), dilated ventricle in 6 (16%), and ventricle dysfunction in 3 (9%) patients. Despite an increased incidence of abnormal flow across the valves on Doppler analysis, no patient had structurally abnormal valves. A majority of patients with SCD had evidence of pulmonary hypertension, which correlated with older age and history of acute chest syndrome. Other structural and functional echocardiographic abnormalities were less common.

Prolonged activated partial thromboplastin time in pregnancy: a brief report

BACKGROUND

Limited data are available regarding causes of prolonged activated partial thromboplastin time (aPTT) in otherwise normal pregnancies. We retrospectively evaluated clinical data of pregnant women in whom an elevated aPTT was noted on routine prenatal testing. Our intent was to identify various causes of prolonged aPTT and to evaluate whether the pregnancies were adversely affected.

METHODS

A retrospective review of medical records of 36 pregnant patients with a prolonged aPTT as the sole abnormal coagulation test seen in the outpatient department of a tertiary care hospital over a period of 4 years.

RESULTS

Patients' median age was 26 (range, 19-41) years and median duration of gestation period was 19 (range, 8-38) weeks. Fifteen patients were primigravida. Of 36 patients, repeated aPTT values were normal in 24 (67%) patients, whereas 12 (33%) patients had persistently elevated aPTT values. Factor XI deficiency was found in 5 patients, lupus anticoagulant in 3 patients, elevated anticardiolipin antibody in 2 patients, and low von Willebrand Factor level in 1 patient. Overall, 23 patients delivered. No patients experienced excessive bleeding or thromboembolism.

CONCLUSION

Factor XI deficiency and antiphospholipid antibody were 2 major abnormalities identified in patients with prolonged aPTT. These coagulopathies were not associated with excessive bleeding or thromboembolism. Repeat normal aPTT in approximately 2 thirds of patients suggests that proper sample collection and processing are important for coagulation assays to avoid erroneous clotting times.

Effect of low-dose warfarin on D-dimer levels during sickle cell vaso-occlusive crisis: a brief report

OBJECTIVE

To evaluate the activation of clotting systems in patients with sickle cell disease (SCD) by measuring the plasma D-dimer level and to determine the effect of low-dose warfarin on D-dimer level during vaso-occlusive crisis.

METHODS

Plasma D-dimer level was measured in 65 blood samples of 37 adult patients with SCD who were hospitalized for vaso-occlusive painful crisis. D-dimer level of patients who were on low-dose warfarin was compared with those patients who were not on any anticoagulation treatment. Analysis of variance (anova) was carried out to determine factors significantly associated with low D-dimer level in patients with SCD. The following factors were included in the anova model; warfarin, homozygous hemoglobin S, history of blood transfusion in past 3 months, hydroxyurea, hemoglobin S%, hemoglobin F%, white blood cell counts, hemoglobin level, platelet count, and plasma fibrinogen level.

RESULTS

Overall median D-dimer level in 65 samples was 2.7 microg fibrinogen equivalent units (FEU)/mL (0.34-4). Patients who were on low-dose warfarin had a median D-dimer level of 0.81 microg FEU/mL (0.34-1.8) compared with 3.1 microg FEU/mL (0.94-4) in those patients who were not on anticoagulation treatment. Using anova to model D-dimer levels, only warfarin was significantly correlated with low D-dimer levels after controlling for other variables.

CONCLUSIONS

Patients with SCD during vaso-occulsive painful crisis have an elevated D-dimer level. Low-dose anticoagulation treatment is associated with a significant reduction in the D-dimer levels.

In vivo regulation of syndecan-3 expression in the rat uterus by 17 beta-estradiol

The immature rat uterus has been extensively used as an in vivo model system to study the molecular mechanisms of steroid hormone actions. In this study, we demonstrated the regulated expression of syndecan-3 in the rat uterus by the steroid hormone 17 beta-estradiol. Administration of a single physiological dose of 17 beta-estradiol (40 microg/kg) to ovariectomized immature animals induced a rapid and transient increase in uterine syndecan-3 mRNA. Transcript levels reached a peak elevation of 3-fold above saline control tissues 4 h after hormone administration. Inhibition of message up-regulation by actinomycin D but not cycloheximide indicated a hormone response dependent on RNA transcription but not new protein synthesis. The estrogenic ligands estriol and tamoxifen were also effective at raising syndecan-3 mRNA levels; however, nonestrogenic ligands, including progesterone, 5 alpha-dihydrotestosterone, and dexamethasone, failed to stimulate a change in mRNA levels. Hormone-induced changes in mRNA led to transient changes in syndecan-3 protein content and significant alteration in the temporal and spatial expression in endometrial epithelial cells. Collectively, these data show that the steroid hormone 17 beta-estradiol, regulates transcription of the syndecan-3 gene in the uterus via an estrogen receptor-dependent mechanism. This estrogen-regulated expression of syndecan-3 may play an important role in changes in tissue ultrastructure crucial for proper uterine growth.

Curcuminoids inhibit the angiogenic response stimulated by fibroblast growth factor-2, including expression of matrix metalloproteinase gelatinase B

We have studied mechanisms controlling activation of the gelatinase B gene (matrix metalloproteinase-9) by fibroblast growth factor-2 (FGF-2) during angiogenesis, and the effects of the natural product curcuminoids on this process. Using a transgenic mouse (line 3445) harboring a gelatinase B promoter/lacZ fusion gene, we demonstrate FGF-2 stimulation of reporter gene expression in endothelial cells of invading neocapillaries in the corneal micropocket assay. Using cultured corneal cells, we show that FGF-2 stimulates DNA binding activity of transcription factor AP-1 but not NF-kappaB and that AP-1 stimulation is inhibited by curcuminoids. We further show that induction of gelatinase B transcriptional promoter activity in response to FGF-2 is dependent on AP-1 but not NF-kappaB response elements and that promoter activity is also inhibited by curcuminoids. In rabbit corneas, the angiogenic response induced by implantation of an FGF-2 pellet is inhibited by the co-implantation of a curcuminoid pellet, and this correlates with inhibition of endogenous gelatinase B expression induced by FGF-2. Angiostatic efficacy in the cornea is also observed when curcuminoids are provided to mice in the diet. Our findings provide evidence that curcuminoids target the FGF-2 angiogenic signaling pathway and inhibit expression of gelatinase B in the angiogenic process.

Treatment of acute idiopathic thrombocytopenic purpura in children. A retrospective evaluation of 120 cases

Acute idiopathic thrombocytopenic purpura (AITP) in children is generally a benign disease with a high frequency of spontaneous remission. Nevertheless the debate over treating or not is still open, because of the high risk of hemorrhage as long as the platelet count remains below 20 x 10(9)/l. We have retrospectively evaluated 120 pediatric cases from our center, receiving different treatments at diagnosis: no treatment (76); IVIG: 400 mg/kg/d for 5 days (28); continuous oral PDN: 1-1.5 mg/kg/d for at least two weeks (16). No patients had been previously treated for AITP. Follow-up is up to fifty months. We found no significant differences as to the percentage of responses among the three groups. We conclude that waiting without treatment is safe and appropriate in most cases; whether the hemorrhagic risk suggests treatment, standard dose continuous oral PDN and IVIG may be equally effective, but IVIG may achieve a significantly faster rise in the platelet count. The timing of treatment and the cost/benefit ratio are discussed.

[Hodgkin's lymphoma with nodular sclerosis. A report of a case with an unusual sternal location at the onset]

The authors report the case of a boy, 9 years old, with a mass in the sternum and the anterior region of the mediastinum. A biopsy of the sternal mass was performed and demonstrated a Hodgkin disease variety nodular sclerosis. The disease was classified as stage III A after that two lymph nodes on the right side of the groin were revealed by lymphography. Therapy consisted of 6 alternate MOPP/ABVD cycles, followed by mantle and inverted Y field radiotherapy for a total of 25 Cg and 5 Cg booster on a sternum. During chemotherapy there was a complete regression of the disease in all sites. At present the patient is healthy and in complete remission and "off therapy", with a follow-up of 32 months. The most interesting aspect of this case is the sternum involvement as the initial manifestation of the nodular sclerosing form of Hodgkin's disease.

ADP ribosylation of type II pulmonary epithelial cell G proteins

Secretion of pulmonary surfactant by type II pulmonary epithelial cells (T2P) is regulated by receptor-mediated mechanisms. In other systems, coupling of receptor-linked signals to intracellular events involves guanine nucleotide-binding proteins (G proteins), but the specific role of G proteins in T2P signaling pathways is poorly defined. The present studies begin to address the role of G proteins in transmembrane signaling in these pneumocytes. Membrane preparations from purified T2Ps demonstrated ADP ribosylation of specific substrates by pertussis, cholera, and botulinum toxins (PT, CT, and BT, respectively). Toxin-dependent T2P substrate labeling from 32P-labeled NAD was dependent on time and membrane protein concentration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography showed ADP ribosylation of membrane substrates of the following molecular masses: PT, 40/41 kDa; CT, 47/51 kDa; BT, 22 kDa. BT-dependent ADP ribosylation of a 22-kDa cytosolic substrate was also observed. Pretreatment of cultured T2P with the individual toxins led to ADP ribosylation of their respective specific substrates in a time-dependent fashion. In cells pretreated with PT or CT, substrates for the complimentary toxins remained available for subsequent ADP ribosylation in vitro. This result supports the specificity of the toxin effects. Basal secretion of the major phospholipid of pulmonary surfactant, disaturated phosphatidylcholine (DSPC) was unaffected in T2P treated with PT, but was stimulated in cells exposed to CT or BT. Neither CT nor BT altered release of lactate dehydrogenase. In cells treated with AMP or with isoproterenol DSPC secretion was stimulated six- to eightfold; preexposure of the cells to CT reduced the response to either agonist by 70%.(ABSTRACT TRUNCATED AT 250 WORDS)

Inflation-associated increases in lung polyamine uptake: role of altered pulmonary vascular flow

Unilateral pneumonectomy in rats leads to rapid compensatory growth of the remaining lung. Previous studies showed that postoperative increases in lung mass are preceded by enhanced uptake of exogenous polyamines and by alterations in adenosine 3',5'-cyclic monophosphate (cAMP) metabolism. These effects are both mimicked in lungs of intact animals subjected to increased inflation in vitro. Partial pneumonectomy also leads to increased flow to the contralateral lung associated with reduced pulmonary vascular resistance. This raises the possibility that the postoperative metabolic response is initiated by changes in pulmonary artery pressure (Pa) or flow, rather than altered inflation. The present studies were designed to investigate this issue. Uptake of exogenous [14C]spermidine by isolated perfused rat lungs was examined over a wide range (greater than 4-fold) of pulmonary flow and ventilation at fixed PaS. Assessment of tissue metabolism from rates of protein synthesis suggested stability of the isolated lung preparations. Apnea (0 ventilation) had no effect on spermidine uptake or flow rate, compared with lungs evaluated under normal conditions of ventilation (inspiratory pressure, 15 cmH2O; positive end expiratory pressure, 2 cmH2O; rate, 70 breaths/min). At both high and low Pa (at a flow rate of 37 +/- 1 and 11 +/- 2 ml/min, respectively, with 0 ventilation), removal of the left lung from the perfusion circuit increased specific right lung flow rate greater than 30% but had no effect on spermidine uptake. Similar alterations in flow rate to the right or both apneic lungs had no effect on the tissue content of cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Stretch-related changes in lung cAMP after partial pneumonectomy

In rats, left pneumonectomy (PNX) initiates rapid compensatory hyperplastic growth of the right lung. Previous work indicated that increased polyamine uptake associated with post-PNX distortion or "stretch" of the remaining tissue and altered adenosine 3',5'-cyclic monophosphate (cAMP) metabolism may play a role in the early phase of the growth response. Evidence was sought to link these observations with the goal of understanding control of compensatory growth. At day 1 or 3 after left PNX in vivo, increased right lung cAMP was associated with activation of the cAMP-dependent protein kinase (PKa). Total PKa activity was unaffected, but the PKa activity ratio (-cAMP/+cAMP) doubled, providing evidence for PNX-associated activation of the kinase in vivo. Neither cAMP nor PKa was altered in sham-operated control lungs. To determine whether increased distension of the right lung after PNX might initiate these changes, lungs of unoperated animals were perfused 40 min in vitro, either without ventilation or with a distending constant positive airway pressure (CPAP) of 20 cmH2O. CPAP rapidly increased uptake of the polyamine spermidine (SPD; 1.5 microM), tissue cAMP, and the PKa activity ratio, in a manner similar to that observed after PNX. Both tissue cAMP and the kinase activity ratio increased with 1 microM forskolin (FSK), as expected, but SPD uptake was unaffected by FSK. FSK did not diminish the CPAP-associated elevations of SPD uptake (P less than 0.01) or cAMP (P less than 0.05), but the kinase was not further activated by CPAP with FSK present.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical mechanisms of cardiac hypertrophy

Rapid cardiac growth in adult rats and neonatal pigs involves more efficient use of existing components of the protein synthesis pathway and synthesis of new ribosomes and mRNA to increase the capacity for protein synthesis. Greater efficiency of synthesis can be induced by mechanical perturbations that stretch the ventricular wall, including increased cardiac work and increased ventricular pressure development in beating hearts, and increased aortic and intraventricular pressure in arrested-drained hearts. The biochemical signal linking stretch to more efficient protein synthesis has not been identified. Preferential synthesis of new ribosomes occurs in the first two hours of exposure of Langendorff preparations to high aortic pressure or within four hours after injection of thyroid hormone into normal rats. The rate of protein degradation is either accelerated or unchanged in hypertrophing hearts but is inhibited by induction of cardiac work or high aortic pressure in Langendorff preparations. Overall, increased capacity for, and efficiency of, protein synthesis are the major factors accounting for cardiac growth.

Faster ribosome synthesis induced by elevated aortic pressure in rat heart

An increase in aortic pressure from 60 to 120 mmHg accelerated ribosomal protein synthesis in rat hearts during 1 or 2 h of labeling with 0.4 mM [3H]phenylalanine. When hearts were perfused with buffer that contained 20 mM glucose and normal plasma concentrations of 19 other amino acids without added insulin, ribosomal protein synthesis relative to the rate of total protein synthesis increased from approximately 0.22 to 0.36 and 0.30 as aortic pressure was raised from 60 to 120 mmHg during 1 or 2 h of labeling, respectively. With the addition of insulin, the relative rate of ribosomal protein synthesis averaged 0.33 at an aortic pressure of 60 mmHg and increased to 0.42 when aortic pressure was raised to 120 mmHg. These results indicate that elevation of aortic pressure has a preferential effect on synthesis of new ribosomes. This response appears to be an early and physiologically significant event in cardiac hypertrophy.