Cerebral mitochondrial dysfunction associated with deep hypothermic circulatory arrest in neonatal swine

OBJECTIVES

Controversy remains regarding the use of deep hypothermic circulatory arrest (DHCA) in neonatal cardiac surgery. Alterations in cerebral mitochondrial bioenergetics are thought to contribute to ischaemia-reperfusion injury in DHCA. The purpose of this study was to compare cerebral mitochondrial bioenergetics for DHCA with deep hypothermic continuous perfusion using a neonatal swine model.

METHODS

Twenty-four piglets (mean weight 3.8 kg) were placed on cardiopulmonary bypass (CPB): 10 underwent 40-min DHCA, following cooling to 18°C, 10 underwent 40 min DHCA and 10 remained at deep hypothermia for 40 min; animals were subsequently rewarmed to normothermia. 4 remained on normothermic CPB throughout. Fresh brain tissue was harvested while on CPB and assessed for mitochondrial respiration and reactive oxygen species generation. Cerebral microdialysis samples were collected throughout the analysis.

RESULTS

DHCA animals had significantly decreased mitochondrial complex I respiration, maximal oxidative phosphorylation, respiratory control ratio and significantly increased mitochondrial reactive oxygen species (P < 0.05 for all). DHCA animals also had significantly increased cerebral microdialysis indicators of cerebral ischaemia (lactate/pyruvate ratio) and neuronal death (glycerol) during and after rewarming.

CONCLUSIONS

DHCA is associated with disruption of mitochondrial bioenergetics compared with deep hypothermic continuous perfusion. Preserving mitochondrial health may mitigate brain injury in cardiac surgical patients. Further studies are needed to better understand the mechanisms of neurological injury in neonatal cardiac surgery and correlate mitochondrial dysfunction with neurological outcomes.

Preoperative cerebral hemodynamics from birth to surgery in neonates with critical congenital heart disease

BACKGROUND

Hypoxic-ischemic white matter brain injury commonly occurs in neonates with critical congenital heart disease. Recent work has shown that longer time to surgery is associated with increased risk for this injury. In this study we investigated changes in perinatal cerebral hemodynamics during the transition from fetal to neonatal circulation to ascertain mechanisms that might underlie this risk.

METHODS

Neonates with either transposition of the great arteries (TGA) or hypoplastic left heart syndrome (HLHS) were recruited for preoperative noninvasive optical monitoring of cerebral oxygen saturation, cerebral oxygen extraction fraction, and cerebral blood flow using diffuse optical spectroscopy and diffuse correlation spectroscopy, 2 noninvasive optical techniques. Measurements were acquired daily from day of consent until the morning of surgery. Temporal trends in these measured parameters during the preoperative period were assessed with a mixed effects model.

RESULTS

Forty-eight neonates with TGA or HLHS were studied. Cerebral oxygen saturation was significantly and negatively correlated with time, and oxygen extraction fraction was significantly and positively correlated with time. Cerebral blood flow did not significantly change with time during the preoperative period.

CONCLUSIONS

In neonates with TGA or HLHS, increasing cerebral oxygen extraction combined with an abnormal cerebral blood flow response during the time between birth and heart surgery leads to a progressive decrease in cerebral tissue oxygenation The results support and help explain the physiological basis for recent studies that show longer time to surgery increases the risk of acquiring white matter injury.

Discordance of patient and physician health status concerns in systemic lupus erythematosus

Objectives To compare the health status concerns of patients with systemic lupus erythematosus (SLE) and of their physicians. Methods Cross-sectional questionnaire study of SLE patients and their treating physicians at a tertiary disease-specific outpatient clinic. Patients and physicians completed a questionnaire regarding their concern about specific disease manifestations and impact on quality of life. For each item, degree of concern was rated on a five-point Likert scale and summarized as median (interquartile range). Ratings between patients and physicians were compared using Mann-Whitney U tests. Results A total of 84 patients and 21 physicians participated. Patients' predominant concerns centred on function and fatigue, whereas physicians' concerns focused on SLE-related organ complications. Of the 10 highest ranked patient concerns, only two were common to the 10 highest ranked physician concerns, while physicians rated seven significantly differently; all 10 highest ranked physician concerns were rated significantly lower by patients. The three highest ranked patient concerns (fatigue, pain and feeling worn out) were routinely assessed by 47.6%, 42.9% and 9.5% of physicians, respectively. Conclusion There was significant discordance between SLE patient and physician health status concerns. Items which were ranked highly by patients were not assessed consistently by physicians, highlighting a significant gap in healthcare communication.

Validation of the Lupus Impact Tracker in an Australian patient cohort

OBJECTIVES

The objective of this article is to validate the Lupus Impact Tracker (LIT), a disease-specific patient-reported outcome (PRO) tool, in systemic lupus erythematosus (SLE) patients in a multi-ethnic Australian cohort.

METHODS

Patients attending the Monash Lupus Clinic were asked to complete the LIT, a 10-item PRO. Psychometric testing assessing criterion validity, construct validity, test-retest reliability (TRT) and internal consistency reliability (ICR) were performed. We compared the LIT scores across patient characteristics, and correlations between LIT scores and SLEDAI-2k, PGA, and SLICC-SDI were examined.

RESULTS

LIT data were obtained from 73 patients. Patients were 84% female with a median age of 41 years, and 34% were Asian. The cohort had mild-moderate disease activity with a median (IQR) Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2k) of 4 (IQR 2-6). The median LIT score was 32.5 (IQR 17.5-50). LIT demonstrated criterion validity against SLEDAI-2k and SDI. Construct validity assessed by confirmatory factor analysis demonstrated an excellent fit (Goodness of fit index 0.95, Comparative Fit Index 1, Root Mean Square Error of Approximation <0.0001). The LIT demonstrated TRT with an overall intraclass correlation coefficient of 0.986 (95% CI 0.968-0.995). ICR was demonstrated with a Cronbach's alpha of 0.838. Patients with disability, low socioeconomic status, or higher disease activity had significantly worse LIT scores.

CONCLUSION

The LIT demonstrated properties consistent with its being valid in this population. Lower socioeconomic status appears to have a significant impact on patient-reported health-related quality of life in SLE.

Fast blood flow monitoring in deep tissues with real-time software correlators

We introduce, validate and demonstrate a new software correlator for high-speed measurement of blood flow in deep tissues based on diffuse correlation spectroscopy (DCS). The software correlator scheme employs standard PC-based data acquisition boards to measure temporal intensity autocorrelation functions continuously at 50 - 100 Hz, the fastest blood flow measurements reported with DCS to date. The data streams, obtained in vivo for typical source-detector separations of 2.5 cm, easily resolve pulsatile heart-beat fluctuations in blood flow which were previously considered to be noise. We employ the device to separate tissue blood flow from tissue absorption/scattering dynamics and thereby show that the origin of the pulsatile DCS signal is primarily flow, and we monitor cerebral autoregulation dynamics in healthy volunteers more accurately than with traditional instrumentation as a result of increased data acquisition rates. Finally, we characterize measurement signal-to-noise ratio and identify count rate and averaging parameters needed for optimal performance.

Cerebral Blood Flow Response to Hypercapnia in Children with Obstructive Sleep Apnea Syndrome

STUDY OBJECTIVES

Children with obstructive sleep apnea syndrome (OSAS) often experience periods of hypercapnia during sleep, a potent stimulator of cerebral blood flow (CBF). Considering this hypercapnia exposure during sleep, it is possible that children with OSAS have abnormal CBF responses to hypercapnia even during wakefulness. Therefore, we hypothesized that children with OSAS have blunted CBF response to hypercapnia during wakefulness, compared to snorers and controls.

METHODS

CBF changes during hypercapnic ventilatory response (HCVR) were tested in children with OSAS, snorers, and healthy controls using diffuse correlation spectroscopy (DCS). Peak CBF changes with respect to pre-hypercapnic baseline were measured for each group. The study was conducted at an academic pediatric sleep center.

RESULTS

Twelve children with OSAS (aged 10.1 ± 2.5 [mean ± standard deviation] y, obstructive apnea hypopnea index [AHI] = 9.4 [5.1-15.4] [median, interquartile range] events/hour), eight snorers (11 ± 3 y, 0.5 [0-1.3] events/hour), and 10 controls (11.4 ± 2.6 y, 0.3 [0.2-0.4] events/hour) were studied. The fractional CBF change during hypercapnia, normalized to the change in end-tidal carbon dioxide, was significantly higher in controls (9 ± 1.8 %/mmHg) compared to OSAS (7.1 ± 1.5, P = 0.023) and snorers (6.7 ± 1.9, P = 0.025).

CONCLUSIONS

Children with OSAS and snorers have blunted CBF response to hypercapnia during wakefulness compared to controls. Noninvasive DCS blood flow measurements of hypercapnic reactivity offer insights into physiopathology of OSAS in children, which could lead to further understanding about the central nervous system complications of OSAS.

Abstract T MP63: Cardiac Diagnosis is the Major Risk for Stroke in Neonates with Complex Congenital Heart Defects

Background and Objectives: Complex congenital heart defects (CHD), which occur in approximately 3 out of 1000 neonates, require invasive open-heart surgery during the first year of life. In a recent prospective study of infants with various forms of complex CHD, 40% of neonates acquired post-operative brain injury including stroke and periventricular leukomalacia (PVL). However, studies identifying specific risk factors of post-operative stroke have been limited. Herein we examine risk factors for post-operative stroke in a mixed cohort of infants with critical CHD.

Methods: Term neonates born with critical CHD from 2009 to present were identified from a single-center prospective study. Exclusion criteria included birth weight less than 2 kg, neonatal depression, perinatal seizures, and evidence of end-organ injury. Magnetic resonance imaging (MRI) to assess pre- and post-operative brain injury was performed immediately prior to and within 10 days after surgery.

Results: Of 102 subjects enrolled, 85 neonates were imaged both pre- and post-operatively. Neonates were diagnosed with either hypoplastic left heart syndrome (HLHS, n=41), transposition of the great arteries (TGA, n=29) or other (n=15). A total of 9 arterial ischemic strokes were observed (10.6%), of which 7/9 were post-operative only. The incidence of stroke was significantly higher in infants with HLHS (6/41, 14.6%) than in infants with TGA (0/29, p=0.03). Time-to-surgery, head circumference, birth weight, duration of deep hypothermic circulatory arrest, and volume of pre- or post-operative PVL were not significantly correlated with incidence of stroke.

Conclusion: Neonates with HLHS have a higher prevalence of post-operative embolic stroke compared to infants with TGA. Although infants with HLHS have been shown to be at a high risk for both post-operative stroke and PVL, incidence of post-operative stroke is not correlated with volume of post-operative PVL.

Inhibition of prostasin-induced ENaC activities by PN-1 and regulation of PN-1 expression by TGF-beta1 and aldosterone

Prostasin has been shown to regulate sodium handling in the kidney. Recently, a serine protease inhibitor, protease nexin-1 (PN-1), was identified as an endogenous inhibitor for prostasin. Therefore, we hypothesized that PN-1 may regulate sodium reabsorption by reducing prostasin activity, and that expression of PN-1 was regulated by transforming growth factor-beta1 (TGF-beta1) or aldosterone, like prostasin. cRNAs for epithelial sodium channel (ENaC), prostasin, and PN-1 were expressed in Xenopus oocytes, and the amiloride-sensitive sodium currents (I(Na)) were measured. The effect of TGF-beta1 and aldosterone on the mRNA and protein abundance of PN-1 and ENaC was detected by real-time polymerase chain reaction and immunoblotting in M-1 cells. Expression of PN-1 substantially decreased prostasin-induced I(Na) by approximately 68% in oocytes. Treatment of M-1 cells with 20 ng/ml TGF-beta1 significantly increased protein expression of PN-1 by 3.8+/-0.5-fold, whereas administration of 10(-6) M aldosterone markedly decreased protein expression of PN-1 to 53.7+/-6.7%. Basolateral, but not apical, application of TGF-beta1 significantly reduced I(eq). To elucidate the involvement of PN-1 in basal ENaC activity, we silenced the expression of PN-1 by using short-interfering RNA. This increased I(eq) by 1.6+/-0.1-fold. Our study indicates that PN-1 could have a natriuretic role by inhibiting prostasin activity and suggests the possibility that aldosterone and TGF-beta reciprocally regulate the expression of PN-1 in renal epithelial cells contributing to salt retention or natriuresis, respectively by an additional mechanism. PN-1 could represent a new factor that contributes to regulation of ENaC activity in the kidney.

Ultrahigh resolution real time OCT imaging using a compact femtosecond Nd:Glass laser and nonlinear fiber

Ultrahigh resolution, real time OCT imaging is demonstrated using a compact femtosecond Nd:Glass laser that is spectrally broadened in a high numerical aperture single mode fiber. A reflective grating phase delay scanner enables broad bandwidth, high-speed group delay scanning. We demonstrate in vivo, ultrahigh resolution, real time OCT imaging at 1 microm center wavelength with <5 microm axial resolution in free space (<4 microm in tissue). The light source is robust, portable, and well suited for in vivo imaging studies.

The first episode of psychosis: the experience of relatives

OBJECTIVE

The aim was to determine the extent of and the correlates of the distress and impact of care families of patients with first episode psychosis were experiencing when they first came for treatment.

METHOD

Subjects were 238 individuals who had presented with a first episode of psychosis and their family members. Family members were assessed with the Psychological General Well-Being Scale, and the Experience of Caregiving Inventory. Patient data included assessment of positive and negative symptoms, depression, quality of life, and substance use.

RESULTS

Family members of these first-episode patients were experiencing distress and difficulties. It was the family's appraisal of the impact of the illness that was associated with their psychological well-being.

CONCLUSION

As the majority of these first episode families are keen to be involved early and have engaged in an intervention programme, the next step should be an evaluation of their involvement to determine if it is effective.

The effects of polishing and bleaching on the colour of discoloured teeth in vivo

Bleaching is an effective method for restoring the colour of discoloured vital teeth. Power bleaching, in particular, in which a bleaching solution containing 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time. The purpose of this study was to determine how polishing or power bleaching the tooth surface affects tooth colour. The subjects selected were patients who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revealed that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post-bleaching change in tooth colour was caused both by elevation of lightness and reduction of yellowness. They also revealed that the colour difference between pre-treatment and post-bleaching does not depend on the type of tooth. These results suggested that power bleaching is an effective technique for improving slightly discoloured vital teeth, regardless of the type of tooth.

Promotion of breastfeeding intervention trial (PROBIT): a cluster-randomized trial in the Republic of Belarus. Design, follow-up, and data validation

This paper summarizes the objectives, design, follow-up, and data validation of a cluster-randomized trial of a breastfeeding promotion intervention modeled on the WHO/UNICEF Baby-Friendly Hospital Initiative (BFHI). Thirty-four hospitals and their affiliated polyclinics in the Republic of Belarus were randomized to receive BFHI training of medical, midwifery, and nursing staffs (experimental group) or to continue their routine practices (control group). All breastfeeding mother-infant dyads were considered eligible for inclusion in the study if the infant was singleton, born at > or = 37 weeks gestation, weighed > or = 2500 grams at birth, and had a 5-minute Apgar score > or = 5, and neither mother nor infant had a medical condition for which breastfeeding was contraindicated. One experimental and one control site refused to accept their randomized allocation and dropped out of the trial. A total of 17,795 mothers were recruited at the 32 remaining sites, and their infants were followed up at 1, 2, 3, 6, 9, and 12 months of age. To our knowledge, this is the largest randomized trial ever undertaken in area of human milk and lactation. Monitoring visits of all experimental and control maternity hospitals and polyclinics were undertaken prior to recruitment and twice more during recruitment and follow-up to ensure compliance with the randomized allocation. Major study outcomes include the occurrence of > or = 1 episode of gastrointestinal infection, > or = 2 respiratory infections, and the duration of breastfeeding, and are analyzed according to randomized allocation ("intention to treat"). One of the 32 remaining study sites was dropped from the trial because of apparently falsified follow-up data, as suggested by an unrealistically low incidence of infection and unrealistically long duration of breastfeeding, and as confirmed by subsequent data audit of polyclinic charts and interviews with mothers of 64 randomly-selected study infants at the site. Smaller random audits at each of the remaining sites showed extremely high concordance between the PROBIT data forms and both the polyclinic charts and maternal interviews, with no evident difference in under- or over-reporting in experimental vs control sites. Of the 17,046 infants recruited from the 31 participating study sites, 16,491 (96.7%) completed the study and only 555 (3.3%) were lost to follow-up. PROBIT's results should help inform decision-making for clinicians, hospitals, industry, and governments concerning the support, protection, and promotion of breastfeeding.

Autocrine TGFbeta signaling mediates vitamin D3 analog-induced growth inhibition in breast cells

In this study, we address whether TGFbeta signaling mediates vitamin D3 analog-induced growth inhibition in nonmalignant and malignant breast cells. Normal mammary epithelial cells (184), immortalized nonmalignant mammary epithelial cells (184A1 and MCF10A), and breast cancer cells (early passage MCF7: MCF7E) were sensitive to the inhibitory effects of vitamin D3 analogs (EB1089 and MC1288) while late passage MCF7 breast cancer (MCF7L) cells were relatively resistant. A similar pattern of sensitivity to TGFbeta was observed with these cells. Thus, the sensitivity to the vitamin D3 analogs correlated with the sensitivity to TGFbeta. MCF7L TGFbetaRII-transfected cells, which have autocrine TGFbeta activity, were more sensitive to EB1089 than MCF7L cells. TGFbeta neutralizing antibody was found to block the inhibitory effects of these analogs. These results are consistent with the idea that autocrine TGFbeta signaling mediates the anti-proliferative effects of the vitamin D3 analogs in these cells. The expression of TGFbeta isoforms and/or TGFbeta receptors was induced by the analogs in the vitamin D3 and TGFbeta sensitive cells. Vitamin D3 analogs did not induce TGFbeta or TGFbeta receptor expression in the resistant MCF7L cells. Therefore, EB1089 induces autocrine TGFbeta activity through increasing expression of TGFbeta isoforms and/or TGFbeta receptors. In addition, EB1089 induced nuclear VDR protein levels in the sensitive 184A1 cells but not in the resistant MCF7L cells. 184A1 cells were more sensitive to EB1089-induced VDR-dependent transactivation than MCF7L cells as measured by a luciferase reporter construct containing the VDRE, indicating a defect of VDR signaling in MCF7L cells. Smad3, a TGFbeta signaling mediator, coactivated VDR-dependent transactivation in 184A1 cells but not in MCF7L cells. These results indicate that Smad3 coactivates VDR to further enhance TGFbeta signaling and vitamin D3 signaling in the sensitive 184A1 cells. The results also indicate that Smad3 is not of itself sufficient to coactivate VDR in TGFbeta/vitamin D3 resistant MCF7L cells and other factors are required. We found that the PI 3-kinase pathway inhibitor LY29004 inhibited the synergy of TGFbeta and EB1089 on VDR-dependent transactivation activity. This indicates that the crosstalk between TGFbeta and vitamin D signaling is also PI 3-kinase pathway dependent.

Imaging needle for optical coherence tomography

We describe a miniature optical coherence tomography (OCT) imaging needle that can be inserted into solid tissues and organs to permit interstitial imaging of their internal microstructures with micrometer scale resolution and minimal trauma. A novel rotational coupler with a glass capillary tube is also presented that couples light from a rotating single-mode fiber to a stationary one. A prototype needle with a 27-gauge (approximately 410-microm) outer diameter has been developed and is demonstrated for in vivo imaging. The OCT needle can be integrated with standard excisional biopsy devices and used for OCT-guided biopsy.