Urinary biomarkers involved in type 2 diabetes: a review

Diabetes mellitus is one of the most challenging health concerns of the 21st century. With at least 30% of the diabetic population remaining undiagnosed, effective and early diagnosis is of critical concern. Development of a diagnostic test, more convenient and reliable than those currently used, would therefore be highly beneficial. Urine as a diagnostic medium allows for non‐invasive detection of biomarkers, including some associated with type 2 diabetes and its complications. This review provides a synopsis of those urinary biomarkers that potentially may provide a basis for the development of improved diagnostic tests. Three main pathways for the sourcing of potential makers are identified: kidney damage, oxidative stress and low‐grade inflammation including atherosclerosis/vascular damage. This review briefly presents each pathway and some of the most relevant urinary biomarkers that may be used to monitor the development or progression of diabetes and its complications. In particular, biomarkers of renal dysfunction such as transferrin, type IV collagen and N‐acetyl‐β‐D ‐glucosaminidase might prove to be more sensitive than urinary albumin, the current gold standard, in the detection of incipient nephropathy and risk assessment of cardiovascular disease. Inflammatory markers including orosomucoid, tumour necrosis factor‐α, transforming growth factor‐β, vascular endothelial growth factor and monocyte chemoattractant protein‐1, as well as oxidative stress markers such as 8‐hydroxy‐2′deoxyguanosine may also be useful biomarkers for diagnosis or monitoring of diabetic complications, particularly kidney disease. However, the sensitivity of these markers compared with albumin requires further investigation. Copyright © 2010 John Wiley & Sons, Ltd.     

Pharmacokinetics, pharmacodynamics, and pharmacogenetics of hydroxyurea treatment for children with sickle cell anemia

Hydroxyurea therapy has proven laboratory and clinical efficacies for children with sickle cell anemia (SCA). When administered at maximum tolerated dose (MTD), hydroxyurea increases fetal hemoglobin (HbF) to levels ranging from 10% to 40%. However, interpatient variability of percentage of HbF (%HbF) response is high, MTD itself is variable, and accurate predictors of hydroxyurea responses do not currently exist. HUSTLE (NCT00305175) was designed to provide first-dose pharmacokinetics (PK) data for children with SCA initiating hydroxyurea therapy, to investigate pharmacodynamics (PD) parameters, including HbF response and MTD after standardized dose escalation, and to evaluate pharmacogenetics influences on PK and PD parameters. For 87 children with first-dose PK studies, substantial interpatient variability was observed, plus a novel oral absorption phenotype (rapid or slow) that influenced serum hydroxyurea levels and total hydroxyurea exposure. PD responses in 174 subjects were robust and similar to previous cohorts; %HbF at MTD was best predicted by 5 variables, including baseline %HbF, whereas MTD was best predicted by 5 variables, including serum creatinine. Pharmacogenetics analysis showed single nucleotide polymorphisms influencing baseline %HbF, including 5 within BCL11A, but none influencing MTD %HbF or dose. Accurate prediction of hydroxyurea treatment responses for SCA remains a worthy but elusive goal.     

Cloning of the cDNA for the putative calcium-sensing receptor and its tissue distribution in sea bream (Sparus aurata)

The cDNA for the calcium-sensing receptor (CaSR) gene has been cloned from the marine teleost Sparus aurata, the sea bream. The isolated clones were 3.3 kb long with an open reading frame of 2820 bp, a 5' UTR of 240 bp, and 3' UTR of 248 bp. The gene codes for a mature peptide of 940 amino acids which has three principal domains; the extracellular region is more than half the total protein, there is a seven-transmembrane domain, and there is a short intracellular domain. There is considerable sequence identity, 91%, shared between the CaSR of sea bream and puffer fish but overall similarities with mammalian CaSR peptides vary between 44% for rat and mouse and 48% with human CaSR. Nevertheless, the 18 cysteine residues of the extracellular domain are present in all sequences so far analysed of which 9 form a cysteine-rich region in sea bream similar to mammalian CaSR. The distribution of CaSR in sea bream tissues detected by in situ hybridisation showed gene expression in epithelia associated with ion transport or ion regulation including the hind gut, chloride cells of the gills, operculum, gall bladder, pituitary adenohypophysis, and coronet cells of the saccus vasculosus; this distribution was confirmed by RT-PCR. By in situ hybridisation, CaSR gene expression was also present in olfactory nerves and leucocytes.     

Ciprofloxacin-induced torsade de pointes

We report a rare case of torsade de pointes, a polymorphic ventricular tachycardia associated with QT interval prolongation, caused by intravenous ciprofloxacin given for pneumonia in a 22-year-old healthy Marine. Although the risk for quinolone-associated torsade de pointes appears to be low, caution is still warranted when given in the presence of pre-existing QT prolongation.     

Novel methodology to comprehensively assess retinal arteriolar vascular reactivity to hypercapnia

PURPOSE: (1) Describe a new methodology that permits the comprehensive assessment of retinal arteriolar vascular reactivity in response to a sustained and stable hypercapnic stimulus. (2) Determine the magnitude of the vascular reactivity response of the retinal arterioles to hypercapnic provocation in healthy, young subjects. METHODOLOGY: Eleven healthy subjects of mean age 27 years (SD 3.43) participated in the study and one eye was randomly selected. A mask attached to a sequential rebreathing circuit, and connected to a gas delivery system, was fitted to the face. To establish baseline values, subjects breathed bottled air for 15 min and at least 6 blood flow measurements of the supero-temporal arteriole were acquired using the Canon Laser Blood Flowmeter (CLBF). Air flow was then decreased until a stable increase in fractional end-tidal CO(2) concentration (F(ET)CO(2)) of 10-15% was achieved. CLBF measurements were acquired every minute (minimum of 6 measurements) during the 20-minute period of elevated F(ET)CO(2). F(et)CO(2) was then reduced to baseline levels, and 6 further CLBF measurements were acquired. Respiratory rate, blood pressure, pulse rate and oxygen saturation were monitored continuously. RESULTS: Retinal arteriolar diameter, blood velocity and blood flow increased during hypercapnia relative to baseline (p=0.0045, p<0.0001 and p<0.0001, respectively). Group mean F(ET)CO(2) showed an increase of 12.0% (SD 3.6) relative to baseline (p<0.0001). CONCLUSIONS: This study describes a new methodology that permits the comprehensive assessment of retinal arteriolar vascular reactivity in response to a sustained and stable hypercapnic stimulus. Retinal arteriolar diameter, blood velocity and blood flow increased significantly in response to a hypercapnic provocation in young, healthy subjects.     

Determinants of exercise function following univentricular versus biventricular repair for pulmonary atresia/intact ventricular septum

This study aimed to determine whether the exercise capacity of patients with pulmonary atresia/intact ventricular septum (PA/IVS) who have undergone biventricular repair is superior to that of patients with single ventricle repairs and to account for any differences. PA/IVS is generally treated with either biventricular (outflow tract reconstruction) or univentricular (Fontan) palliation. Although biventricular repair is believed to result in superior exercise function, this theory is untested. Symptom-limited programmed bicycle ergonometry with expiratory gas analysis was prospectively performed on all patients with PA/IVS >7 years old seen over 18 months. Nineteen biventricular and 10 Fontan patients (mean age 16.5 +/- 6.5 vs 12.7 +/- 5.0 years, p = 0.12) were enrolled. The exercise capacity of biventricular patients was not statistically superior to that of Fontan patients (predicted peak VO2 83.5 +/- 21% vs 76.0 +/- 17.5%, p = 0.34), although chronotropic function and ventilatory efficiency were significantly better in the former. The peak exercise capacity varied widely within each group, and there was considerable overlap between biventricular and Fontan patients. Within groups, imaging studies did not reliably predict exercise capacity. Most patients in each group had subnormal peak VO2, and there was a trend toward impaired performance with increasing age regardless of type of repair. In conclusion, biventricular repair may not guarantee superior exercise performance over single-ventricle palliation in PA/IVS. Regardless of repair type, aerobic capacity may deteriorate with age and is not reliably predicted by noninvasive imaging. These findings underscore the need for a quantitative, proactive approach to the assessment and preservation of exercise function.     

Two new phosphoglycerate kinase mutations associated with chronic haemolytic anaemia and neurological dysfunction in two patients from Spain

We report two previously undescribed mutations of the phosphoglycerate kinase gene (PGK1) leading to enzyme deficiency. In both cases, the patients were of Spanish origin and they exhibited a severe life-long chronic haemolytic anaemia associated with progressive neurological impairment. Sequence analysis of the first patient's entire PGK1 gene found a novel missense mutation (140T > A). This mutation caused an amino acid change of Ile to Asn at 46th position from the NH(2)-terminal serine residue (Ile46Asn), which has been called PGK-Barcelona based on the place of origin of the patient. In the second patient, a G to A transversion was discovered at nucleotide 958 (958G > A). This caused a Ser319Asn amino acid substitution. Since this mutation had not been previously described, the provisional name of PGK-Murcia was given to this deficient enzyme. The crystal structure of porcine PGK was used as a molecular model to investigate how these mutations may affect enzyme structure and function. In both cases, the mutations did not modify any of the PGK binding sites for ATP or 3PG, so their consequence is related to a loss of enzyme stability rather than a decrease of enzyme catalytic function.     

Production of chemokines in the lungs of infants with severe respiratory syncytial virus bronchiolitis

BACKGROUND: Respiratory syncytial virus (RSV) bronchiolitis in infants is characterized by a massive neutrophilic infiltrate into the airways. Chemokines direct migration of leukocytes and contribute to the pathogenesis of RSV disease. However, little is known about pulmonary chemokine responses to RSV in humans. Our aim was to characterize the production of chemokines in the lungs of infants with RSV bronchiolitis and how this production changes over time. METHODS: Chemokine mRNA and the concentration of chemokines were measured in nonbronchoscopic bronchoalveolar lavage (BAL) samples from infants with RSV bronchiolitis and from control infants. In infants with RSV bronchiolitis, changes in the concentrations of chemokines during the 7 days after intubation and between the days of intubation and extubation were examined. RESULTS: The production of chemokines within the lower respiratory tract was shown in all patients with RSV bronchiolitis. CXC chemokines (particularly CXCL10/interferon-inducible protein 10 and CXCL8/interleukin-8) were found to be the most abundant, but CC chemokines (CCL2/monocyte chemotactic protein 1 and CCL3/macrophage inflammatory protein-1 alpha) were also present. Concentrations of some of these chemokines remained elevated over the course of the illness, whereas others decreased steadily. No differences in the concentrations were found between the days of intubation and extubation. CONCLUSIONS: CXC chemokines predominate within the RSV-infected lung. Much of this response comes from inflammatory cells within the lower respiratory tract. Chemokine response patterns vary over time, possibly indicating different cellular sources for individual chemokines in the RSV-infected lung.