Vitamin B6 metabolites in idiopathic calcium stone formers: no evidence for a link to hyperoxaluria

Vitamin B6 metabolites and their potential correlates to urinary oxalate excretion in idiopathic calcium stone formers (ICSF) compared with healthy subjects were investigated. This clinical study was performed in a population of male ICSF with (Hyperoxalurics, n=55) or without hyperoxaluria (Normooxalurics, n=57) as well as in 100 healthy male control subjects. Pyridoxal 5'-phosphate serum concentration (S-pyridoxal 5'P) and 24-h urinary excretion of 4-pyridoxic acid (U-4pyridoxic acid) were measured using HPLC; 24-h urinary excretion of oxalate (U-oxalate) was measured concurrently. A subgroup of subjects (40 Hyperoxalurics, 15 Normooxalurics and 50 controls) underwent the same measurements before and after 7-day pyridoxine loading per os (pyridoxine hydrochloride, 300mg/d). Under usual conditions, U-4pyridoxic acid was similar in the three groups, whereas mean S-pyridoxal 5'P was significantly lower (p<0.0001) in the Hyperoxalurics (59.6±21.2nmol/L) and in the Normooxalurics (64.9±19.7nmol/L) than in the controls (86.0±31.0nmol/L). No correlation could be found between U-oxalate and U-4pyridoxic acid or S-pyridoxal 5'P. After B6 loading, S-pyridoxal 5'P was still significantly lower in the Hyperoxalurics (415±180nmol/L, p<0.001) and in the Normooxalurics (429±115nmol/L, p=0.036) than in the controls (546±180nmol/L), although there was no difference between groups for U-4pyridoxic acid. No correlation in any group could be found between changes in U-oxalate and changes in U-4pyridoxic acid or S-pyridoxal 5'P. Although there is no vitamin B6 deficiency in ICSF with or without hyperoxaluria, these patients, on average, have lower levels of S-pyridoxal 5'P than healthy subjects. However, this slight decrease does not seem to account for idiopathic hyperoxaluri

Epigenetic expansion of VHL-HIF signal output drives multiorgan metastasis in renal cancer.

Inactivation of the von Hippel-Lindau tumor suppressor gene, VHL, is an archetypical tumor-initiating event in clear cell renal carcinoma (ccRCC) that leads to the activation of hypoxia-inducible transcription factors (HIFs). However, VHL mutation status in ccRCC is not correlated with clinical outcome. Here we show that during ccRCC progression, cancer cells exploit diverse epigenetic alterations to empower a branch of the VHL-HIF pathway for metastasis, and the strength of this activation is associated with poor clinical outcome. By analyzing metastatic subpopulations of VHL-deficient ccRCC cells, we discovered an epigenetically altered VHL-HIF response that is specific to metastatic ccRCC. Focusing on the two most prominent pro-metastatic VHL-HIF target genes, we show that loss of Polycomb repressive complex 2 (PRC2)-dependent histone H3 Lys27 trimethylation (H3K27me3) activates HIF-driven chemokine (C-X-C motif) receptor 4 (CXCR4) expression in support of chemotactic cell invasion, whereas loss of DNA methylation enables HIF-driven cytohesin 1 interacting protein (CYTIP) expression to protect cancer cells from death cytokine signals. Thus, metastasis in ccRCC is based on an epigenetically expanded output of the tumor-initiating pathway

Vitamin B6 metabolites in idiopathic calcium stone formers: no evidence for a link to hyperoxaluria

Vitamin B6 metabolites and their potential correlates to urinary oxalate excretion in idiopathic calcium stone formers (ICSF) compared with healthy subjects were investigated. This clinical study was performed in a population of male ICSF with (Hyperoxalurics, n=55) or without hyperoxaluria (Normooxalurics, n=57) as well as in 100 healthy male control subjects. Pyridoxal 5’-phosphate serum concentration (S-pyridoxal 5’P) and 24-h urinary excretion of 4-pyridoxic acid (U-4pyridoxic acid) were measured using HPLC; 24-h urinary excretion of oxalate (U-oxalate) was measured concurrently. A subgroup of subjects (40 Hyperoxalurics, 15 Normooxalurics and 50 controls) underwent the same measurements before and after 7-day pyridoxine loading per os (pyridoxine hydrochloride, 300 mg/d). Under usual conditions, U-4pyridoxic acid was similar in the three groups, whereas mean S-pyridoxal 5’P was significantly lower (p<0.0001) in the Hyperoxalurics (59.6±21.2 nmol/L) and in the Normooxalurics (64.9±19.7 nmol/L) than in the controls (86.0±31.0 nmol/L). No correlation could be found between U-oxalate and U-4pyridoxic acid or S-pyridoxal 5’P. After B6 loading, S-pyridoxal 5’P was still significantly lower in the Hyperoxalurics (415±180 nmol/L, p<0.001) and in the Normooxalurics (429±115 nmol/L, p=0.036) than in the controls (546±180 nmol/L), although there was no difference between groups for U-4pyridoxic acid. No correlation in any group could be found between changes in U-oxalate and changes in U-4pyridoxic acid or S-pyridoxal 5’P. Although there is no vitamin B6 deficiency in ICSF with or without hyperoxaluria, these patients, on average, have lower levels of S-pyridoxal 5’P than healthy subjects. However, this slight decrease does not seem to account for idiopathic hyperoxaluria

Neck osteotomy for malunion of neglected radial neck fractures in children: a report of 2 cases

BACKGROUND: Radial neck fractures are a common injury in children as a result of a fall on an extended and supinated outstretched hand. METHODS: We present 2 cases of osteotomy of the neck of the radius performed in 2 children with neglected radial neck fractures. RESULTS: Preoperatively, both patients complained of pain and severely reduced mobility of the elbow. Surgery was performed at 6 weeks and 3 months, respectively, after the initial injury and the 2 children were reviewed at 6 and 16 months follow-up. Osteotomies healed within the usual time and no avascular necrosis of the radial head, proximal radioulnar synostosis, or myositis ossificans were observed. The Mayo Elbow Performance Index Score improved significantly after the operation with the 2 patients rated as excellent. CONCLUSIONS: In this small series, we present a novel technique of proximal osteotomy of the radius to correct this deformity in children. LEVEL OF EVIDENCE: Case series, level IV evidence

Ten years of antiretroviral therapy: Incidences, patterns and risk factors of opportunistic infections in an urban Ugandan cohort.

BACKGROUND:Despite increased antiretroviral therapy (ART) coverage and the raised CD4 threshold for starting ART, opportunistic infections (OIs) are still one of the leading causes of death in sub-Saharan Africa. There are few studies from resource-limited settings on long-term reporting of OIs other than tuberculosis. METHODS:Patients starting ART between April 2004 and April 2005 were enrolled and followed-up for 10 years in Kampala, Uganda. We report incidences, patterns and risk factors using Cox proportional hazards models of OIs among all patients and among patients with CD4 cell counts >200 cells/μL. RESULTS:Of the 559 patients starting ART, 164 patients developed a total of 241 OIs during 10 years of follow-up. The overall incidence was highest for oral candidiasis (25.4, 95% confidence interval (CI): 20.5-31.6 per 1000 person-years of follow-up), followed by tuberculosis (15.3, 95% CI: 11.7-20.1), herpes zoster (12.3, 95% CI: 9.1-16.6) and cryptococcal meningitis (3.0, 95% CI: 1.7-5.5). Incidence rates for all OIs were highest in the first year after ART initiation and decreased with the increase of the current CD4 cell count. Factors independently associated with development of OIs were baseline nevirapine-based regimens, time-varying higher viral load, time-varying lower CD4 cell count and time-varying lower hemoglobin. In patients developing OIs at a current CD4 cell count >200 cells/μL, factors independently associated with OI development were time-varying increase in viral load and time-varying decrease in hemoglobin, whereas a baseline CD4 cell count <50 cells/μL was protective. CONCLUSION:We report high early incidences of OIs, decreasing with increasing CD4 cell count and time spent on ART. Ongoing HIV replication and anemia were strong predictors for OI development independent of the CD4 cell count. Our findings support the recommendation for early initiation of ART and suggest close monitoring for OIs among patients recently started on ART, with low CD4 cell count, high viral load and anemia

Taking advantage of tumor cell adaptations to hypoxia for developing new tumor markers and treatment strategies

Cancer cells in hypoxic areas of solid tumors are to a large extent protected against the action of radiation as well as many chemotherapeutic drugs. There are, however, two different aspects of the problem caused by tumor hypoxia when cancer therapy is concerned: One is due to the chemical reactions that molecular oxygen enters intoin therapeutically targeted cells. This results in a direct chemical protection against therapy by the hypoxic microenvironment which has little to do with cellular biological regulatory processes. This part of the protective effect of hypoxia has been known for more than half a century and has been studied extensively. However, in recent years more focus has been put into the other aspect of hypoxia, namely the effect of this microenvironmental condition on selecting cells with certain genetical pre-requisites that are negative with respect to patient prognosis. There are adaptive mechanisms, where hypoxia induces regulatory cascades in cells resulting in a changed metabolism or changes in extra cellular signalling. These processes may lead to changes in cellular intrinsic sensitivity to treatment irrespective of oxygenation and furthermore, may also have consequences for tissue organization. Thus, the adaptive mechanisms induced by hypoxia itself may have a selective effect on cells with a fine-tuned protection against damage and stress of many kinds. It therefore could be that the adaptive mechanisms may be taken advantage of for new tumor labelling/imaging and treatment strategies. One of the Achilles’ heels of hypoxia research has always been exact measurements of tissue oxygenation as well as control of oxygenation in biological tumor models. Thus, development of technology that can ease this control is vital in order to study mechanisms and perform drug development under relevant conditions. An integrated EU Framework project 2004-2009, termed Euroxy, demonstrates several pathways involved in transcription and translation control of the hypoxic cell phenotype and evidence of cross talk with responses to pH and redox changes. The carbon anhydrase isoenzyme CA IX was selected for further studies due to its expression on the surface of many types of hypoxic tumors. The effort has lead to marketable culture flaks with sensors and incubation equipment and the synthesis of new drug candidates against new molecular targets. New labelling/imaging methods for cancer diagnosing and imaging of hypoxic cancer tissue now are being tested in xeno-graft models and also are in early clinical testing while new potential anticancer drugs are undergoing tests using xenografted tumor cancers. The present paper describes the above results in individual consortium partner presentations