PARP-3 associates with polycomb group bodies and with components of the DNA damage repair machinery

Poly(ADP-ribose) polymerase 3 (PARP-3) is a novel member of the PARP family of enzymes that synthesize poly(ADP-ribose) on themselves and other acceptor proteins. Very little is known about this PARP, which is closely related to PARP-1 and PARP-2. By sequence analysis, we find that PARP-3 may be expressed in two isoforms which we studied in more detail to gain insight into their possible functions. We find that both PARP-3 isoforms, transiently expressed as GFP or FLAG fusions, are nuclear. Detection of endogenous PARP-3 with a specific antibody also shows a widespread nuclear distribution, appearing in numerous small foci and a small number of larger foci. Through co-localization experiments and immunoprecipitations, the larger nuclear foci were identified as Polycomb group bodies (PcG bodies) and we found that PARP-3 is part of Polycomb group protein complexes. Furthermore, using a proteomics approach, we determined that both PARP-3 isoforms are part of complexes comprising DNA-PKcs, PARP-1, DNA ligase III, DNA ligase IV, Ku70, and Ku80. Our findings suggest that PARP-3 is a nuclear protein involved in transcriptional silencing and in the cellular response to DNA damage.

Acetylcholine receptor antibodies in myasthenia gravis are associated with greater risk of diabetes and thyroid disease

OBJECTIVE

Myasthenia gravis (MG) may be associated with the presence of acetylcholine receptor antibodies (AChRAb) [seropositive MG (SPMG)] or their absence [seronegative MG (SNMG)]. Along with features of MG, the presence of the AChRAb may relate to the existence of other immune-mediated diseases. We sought to determine the association of SPMG with other potential autoimmune diseases.

METHODS

A retrospective evaluation of prospectively identified MG patients at a tertiary care center was performed, with patients separated into SPMG and SNMG. Prevalence of other immune-mediated disorders, as well as the epidemiology, sensitivity of diagnostic testing, and thymic pathology, was contrasted between both patient groups.

RESULTS

Of the 109 MG patients identified, 66% were SPMG. SPMG was associated with a greater likelihood of significant repetitive stimulation decrement, the presence of either thymoma or thymic hyperplasia, and the presence of thyroid disease. In addition, all patients with a diagnosis of diabetes, concurrent with MG, were found to be SPMG.

CONCLUSIONS

AChRAb and SPMG impart not only a distinctive clinical and electrophysiological phenotype of MG, but are also associated with the heightened presence of endocrinological disease.

External quality assurance of molecular analysis of haemochromatosis gene mutations

BACKGROUND

The Royal College of Pathologists of Australasia Quality Assurance Programs has conducted an external quality assurance programme for the testing of the haemochromatosis gene (HFE) mutations C282Y and H63D.

METHODS

A total of 10 surveys have been undertaken over a period of 6 years from 2000 to 2005.

RESULTS

Of the 3016 responses received, the overall success rate was found to be 99.47% (3000/3016). A total of 16 errors were found, 6 for C282Y and 10 for H63D. Only one sample was associated with more than one error, in which 2 of 23 respondents classified a normal sample as heterozygotic for H63D. Overall performance was observed to vary minimally between surveys, from a low of 91.3% correct (21/23 responses) for a normal sample to 100% correct in most (85/100) samples. Of the 10 complete surveys, four returned a 0% error rate. In one survey in 2004, seven incorrect responses were returned by one laboratory, all of which were secondary to transcriptional errors. Overall success rates per assay were 99.61% (1532/1538) for C282Y and 99.32% (1468/1478) for H63D. Over a period of 6 years from 2000 to 2005, the proportion of respondents using polymerase chain reaction (PCR) and restriction enzyme analysis fell from 85% to around 30%, whereas the proportion of laboratories using real-time PCR rose from 5% to around 55%, as indicated by the questionnaire surveys of methods used by participants.

DISCUSSION

Encouraging levels of testing proficiency for two common genetic mutations are indicated by these data, but they also confirm the need for participation of molecular diagnostic laboratories in external quality assurance programmes to ensure the ongoing provision of high-quality genetic testing services.

Rescue and regeneration of injured peripheral nerve axons by intrathecal insulin

Insulin peptide, acting through tyrosine kinase receptor pathways, contributes to nerve development or repair. In this work, we examined the direction, impact and repertoire of insulin signaling in vivo during peripheral nerve regeneration in rats. First, we demonstrated that insulin receptor is expressed on lumbar dorsal root ganglia neuronal perikarya using immunohistochemistry. Immunoblots and polymerase chain reactions confirmed the presence of both alpha and beta insulin receptor subunits in dorsal root ganglia. In vivo and in vitro assessment of dorsal root ganglion neurons showed preferential localization of insulin receptor to perikaryal sites. In vivo, intrathecal delivery of fluorescein isothiocyanate-labeled insulin identified localization around dorsal root ganglia neurons. The direction and impact of potential insulin signaling was evaluated by concurrently delivering insulin or carrier over a 2 week period using mini-osmotic pumps, either intrathecally, near nerve, or with both deliveries, following a selective sural nerve crush injury. Only intrathecal insulin increased the number and maturity of regenerating sensory sural nerve axons distal to the crush site. As well, only intrathecal insulin rescued retrograde loss of sural axons after crush. In a separate experiment, insulin also rescued retrograde loss and atrophy of deep peroneal, largely motor, axons post-injury. Intrathecal insulin increased the expression of calcitonin-gene-related peptide in regenerating sprouts, increased the number of visualized regenerating fiber clusters, and reduced downregulation of calcitonin-gene-related peptide in dorsal root ganglia neurons. Insulin delivered intrathecally does not appear to influence expression of insulin-like growth factor-1 at dorsal root ganglion neurons or near peripheral nerve injury, but was associated with upregulation of insulin receptor alpha subunit in dorsal root ganglia. Intrathecal insulin delivery was associated with greater recovery of thermal sensation and longer distances to stimulus response with the pinch test following sural nerve crush. Insulin signaling at neuron perikarya can drive distal sensory axon regrowth, rescue retrograde alterations of axons and alter axon peptide expression. Moreover, such actions are associated with upregulation of its own receptor.

HIV seroprevalence, uptake of interventions to reduce mother-to-child transmission and birth outcomes in greater Kingston, Jamaica

BACKGROUND

The seroprevalence of HIV among pregnant women in the Caribbean is 2-3% and increasing. The Kingston Paediatric and Perinatal HIV Programme is developing and implementing a unified programme to eliminate mother-to-child transmission (MTCT) of HIV in Kingston, Jamaica.

METHODS

Pregnant women presenting to Kingston Metropolitan Antenatal Clinics, Victoria Jubilee Hospital, Spanish Town Hospital and the University Hospital of the West Indies had HIV serology performed by ELISA, or by the new Determine Rapid Test after receiving group counselling. HIV-positive women were referred to High Risk Antenatal Clinics. Antiretroviral prophylaxis with zidovudine (AZT), or nevirapine was given. Care was administered using a standard protocol by a multi-disciplinary team of public and academic healthcare personnel.

RESULTS

In year one, 19,414 women delivered Among 14,054 women who started antenatal care for this period, 5,558 (40%) received group counselling and 7,383 (53%) received HIV-testing. During the fourth quarter of follow-up, these comparative rates were 66% (2049/3 118) and 72% (2260/3118) respectively. HIV seroprevalence overall was 2.1% (152/7 383). One hundred and seven HIV+ women at varying gestational ages were identified in the programme, 72 had so far received AZT and nine nevirapine (76%). 0f 84 deliveries, birth outcomes were 75 live births (89%), six neonatal deaths and four maternal deaths (all from HIV/AIDS). Major challenges include repeat pregnancies of 36% despite prior knowledge of HIV seropositivity and poor partner notification with only 30% (32) having a HIV-test. Although rates of HIV testing in pregnant women in Greater Kingston are increasing, rates of testing overall remain sub-optimal. On the labour ward, there was sub-optimal identification of the HIV+ pregnant woman and administration of AZT chemoprophylaxis, along with issues of patient confidentiality and stigma.

CONCLUSION

This programme needs strengthening in order to reduce maternal-fetal transmission of HIV in Greater Kingston, Jamaica "pMTCT-PLUS, or comprehensive family-centred care, is the next step".

A randomised study comparing peripheral blood progenitor mobilisation using intermediate-dose cyclophosphamide plus lenograstim with lenograstim alone

We conducted a prospective randomised study to compare the efficiency of out-patient progenitor cell mobilisation using either intermediate-dose cyclophosphamide (2 g/m(2)) and lenograstim at 5 micrograms/kg (Cyclo-G-CSF group, n=39) or lenograstim alone at 10 micrograms/kg (G-CSF group, n=40). The end points were to compare the impact of the two regimens on mobilisation efficiency, morbidity, time spent in hospital, the number of apheresis procedures required and engraftment kinetics. Successful mobilisation was achieved in 28/40 (70%) in the G-CSF group vs 22/39 (56.4%) for Cyclo-G-CSF (P=0.21). The median number of CD34+ cells mobilised was 2.3 x 10(6)/kg and 2.2 x 10(6)/kg for G-CSF and cyclo-G-CSF arms following a median of two apheresis procedures. Nausea and vomiting and total time spent in the hospital during mobilisation were significantly greater after Cyclo-G-CSF (P<0.05). Rapid neutrophil and platelet engraftment was achieved in all transplanted patients in both groups. In conclusion, G-CSF at 10 micrograms/kg was as efficient at mobilising progenitor cells as a combination of cyclophosphamide and G-CSF with reduced hospitalisation and side effects and prompt engraftment. When aggressive in-patient cytoreductive regimens are not required to both control disease and generate progenitor cells, the use of G-CSF alone appears preferable to combination with intermediate-dose cyclophosphamide.

Destabilization of fast-ion-induced long sawteeth by localized current drive in the JET tokamak

In a tokamak fusion reactor the energetic alpha particles will transiently stabilize the magnetohydrodynamic activity causing sawtooth oscillations. The crash events terminating long sawtooth free periods can provide seed islands for neoclassical tearing modes [Phys. Rev. Lett. 88, 105001 (2002)]]. To shorten the sawtooth periods localized current drive near the q=1 surface is a possibility. This Letter provides the first experimental evidence for the effectiveness of this method in the different physics regime associated with fast-ion-induced long sawteeth on the JET tokamak.

Ischemic Fasciitis: An Unusual Vulvovaginal Spindle Cell Lesion

Ischemic fasciitis is a benign reactive lesion that most commonly occurs in elderly, immobile patients in weight-bearing areas that are subject to intermittent ischemia with subsequent tissue breakdown and regenerative changes. The lesion can be clinically and pathologically mistaken for malignancy. Here we describe the first reported case of ischemic fasciitis of the vulvovaginal region in a 20-year-old paraplegic woman who presented with a clinically suspicious vulvar swelling. Histologic examination showed surface ulceration and underlying fibrinoid necrosis with surrounding reactive atypical fibroblast-like cells and small blood vessels, the characteristic histologic features of ischemic fasciitis.

The albuminuric action of atrial natriuretic peptide is not modified by ACE-inhibition with perindopril in Type 2 diabetes

AIMS

Atrial natriuretic peptide (ANP) increases urine albumin excretion (UAER) in humans with Type 1 diabetes. The aim of this study was to establish if ANP increases UAER in microalbuminuric subjects with Type 2 diabetes and to examine whether the albuminuric action of ANP was inhibited by pre-treatment with the ACE-inhibitor perindopril.

METHODS

Seven microalbuminuric, normotensive males with Type 2 diabetes were entered into a randomised, double-blind, three-armed study of (i) intravenous infusion of ANP (0.25 microg/kg/min in 0.9% NaCl) after 3 weeks' pre-treatment with placebo, (ii) intravenous infusion of vehicle (0.9% NaCl only) after 3 weeks' pre-treatment with placebo, or (3) intravenous infusion of ANP (0.25 microg/kg/min in 0.9% NaCl) after 3 weeks' pre-treatment with perindopril, 4 mg daily.

RESULTS

Baseline parameters were similar on all three study days. During the placebo/vehicle arm there was no change in urine flow rate (UFR, P=0.61), urine cyclic guanosine monophosphate (UcGMP P=0.48) or UAER (P=0.99). During the placebo/ANP arm there was a rise in UFR [13.7+/-2.8 (mean+/-sd) to 25.7+/-7.7 mL/min, P<0.001], UcGMP (60.0+/-36.6 to 160.8+/-118.5 micromol/mmolCr, P=0.045) and UAER [5.13 [2.4-11.6][median (range)] to 71.6 [21.6-175.1] mg/mmolCr, P<0.001]. Pre-treatment with perindopril did not alter the changes in UFR (P=0.63), UcGMP (P=0.46) or UAER (P=0.99) to infusion of ANP, compared with the placebo/ANP arm.

CONCLUSION

ANP increases UAER in microalbuminuric patients with Type 2 diabetes and the albuminuric action of ANP is not inhibited by pre-treatment with the ACE inhibitor perindopril.

Factors associated with size and proportionality at birth in term Jamaican infants

The objective of this study was to identify the factors associated with size and proportionality at birth in a cohort of term infants established to investigate their growth and development. One hundred and forty term low-birth-weight (birth-weight < 2,500 g) infants and 94 normal birth-weight infants (2,500- < 4,000 g) were recruited within 48 hours of birth at the main maternity hospital, Kingston, Jamaica. Birth anthropometry and gestational age were measured, and maternal information was obtained by interview and from hospital records. Controlling for gestational age, variables independently associated with birth-weight were rate of weight gain in the second half of pregnancy, maternal height, haemoglobin level < 9.5 microg/dL, time of first attendance in antenatal clinic, birth order, pre-eclampsia, and consumption of alcohol, with 33% of the variance in birth-weight explained. Birth length was associated only with maternal height and age, while measures of proportionality (ponderal index and head/length ratio) were associated with characteristics of the environment in late pregnancy, including rate of weight gain, weight in late pregnancy, and pre-eclampsia. The variation in maternal characteristics associated with size or proportionality at birth may reflect the times during gestation when different aspects of growth are most affected.

Dynamic three-dimensional color Doppler ultrasound of human fetal intracardiac flow

OBJECTIVES

To develop dynamic three-dimensional ultrasound techniques for prenatal imaging of the intracardiovascular flow as well as the cardiovascular structure to address difficulties in assessing the spatially complex hemodynamics and morphology of the fetal heart.

METHODS

Gray-scale and color (velocity) Doppler echocardiography were performed on 12 fetuses to provide serial anatomical and rheological tomograms which were spatially registered in three dimensions. Using a second ultrasound machine simultaneously, spectral Doppler ultrasound was performed to record umbilical arterial waveforms, thus providing the temporal (fourth) dimension in terms of the cardiac cycle and facilitating removal of motion artifacts.

RESULTS

Acquisitions were successful in eight of 15 attempts. Imaging of the flow of blood in four dimensions was achieved in six of the eight datasets. In one case with complex cardiac malformations, three-dimensional reconstructions at systole and diastole offered dynamic diagnostic views not appreciated on the cross-sectional images.

CONCLUSIONS

Our novel technique has made possible the prenatal visualization of the spatial distribution and true direction of intracardiac flow of blood in four dimensions in the absence of motion artifacts. The technique suggests that diagnosis of cardiac malformations can be made on the basis of morphological and hemodynamic changes throughout the entire cardiac cycle, offering unique and significant information complementary to conventional techniques. Further work to integrate the several non-purpose-built machines into a single system will improve the rate of acquisition of data, and may provide a new means of imaging and modeling structure and hemodynamics, not only for the fetal heart but for many other moving body parts.

Clinical use of Infliximab in Crohn's disease: the Edinburgh experience

Infliximab is an established treatment for steroid-resistant and fistulating Crohn's disease. Although efficacy has been shown in clinical trials, financial implications often limit its use and limited data exist regarding clinical practice.

AIMS

To audit the clinical effectiveness of Infliximab.

METHODS

We prospectively audited 50 consecutive patients [28 females; median age, 34 years (17-70 years)]. Disease activity and response rates were assessed by the Harvey-Bradshaw index. Clinical and disease data were collected and blood was taken for inflammatory markers, complement and double-stranded DNA antibodies. Patients received Infliximab at 5 mg/kg and were followed for 12 weeks.

RESULTS

Indications for Infliximab were refractory Crohn's disease in 39 patients, fistulating Crohn's disease in six, pyoderma gangrenosum in one, pouchitis in two and coeliac disease in two. Thirty-one (79%) of the refractory Crohn's disease patients and four (66%) of the fistulating patients responded at 4 weeks. Twenty-one (54%) of the refractory Crohn's disease patients had a continued response at 12 weeks. Perianal disease was more prevalent in non-responders (7/8 vs. 12/31, P < 0.02).

CONCLUSIONS

Response rates to Infliximab in our group are comparable to those of clinical trials. Despite the expense, it remains a useful adjunct to treatment in this otherwise difficult group of patients. Patients with perianal disease responded less well in our cohort.

Relationship between the G894T polymorphism (Glu298Asp variant) in endothelial nitric oxide synthase and nitric oxide-mediated endothelial function in human atherosclerosis

Nitric oxide (NO), produced by endothelial nitric oxide synthase (eNOS), plays important roles in normal vascular homeostasis, and reduced endothelial NO bioactivity is an important feature of vascular disease states. The Glu298Asp (G894T) polymorphic variant of eNOS has been associated with vascular disease, but functional data are lacking. Accordingly, we examined the relationships between NO-mediated endothelial function, the presence of the eNOS Glu298Asp variant, and clinical risk factors for atherosclerosis. Endothelium-dependent vasorelaxations to different agonists were determined in human saphenous veins obtained from patients with coronary artery disease and identified risk factors (n = 104). Patients were genotyped for the eNOS G894T polymorphism. Nitric oxide-mediated endothelial vasorelaxations were highly variable between patients. Reduced vasorelaxations were associated with increased number of clinical risk factors for atherosclerosis (r = - 0.54, P < 0.001), whereas the Glu298Asp variant was not associated with any differences in contractions to phenylephrine, NO-mediated vasorelaxations to acetylcholine, bradykinin or calcium ionophore, or relaxations to the NO donor sodium nitroprusside. Increased atherosclerotic risk factors, but not the presence of the eNOS Glu298Asp variant, are associated with impaired nitric oxide-mediated endothelial vasomotor function, suggesting that this polymorphism does not have a major direct functional effect on vascular eNOS activity in human atherosclerosis.