Challenges in clinical identification of right ventricular dysfunction in preterm infants with persistent pulmonary hypertension of the newborn

BACKGROUND

Right ventricular dysfunction, typically qualitatively diagnosed (Q-RVd) in preterm infants, requires echocardiography which is not always acutely available. We aimed to identify clinical indices of Q-RVd in very preterm infants (gestational age, GA <32 weeks) with persistent pulmonary hypertension of newborn (PPHN) and examine the reliability and validity of Q-RVd.

METHODS

Forty-seven infants with mean ± SD GA of 26.8 ± 2.7 weeks who had targeted neonatal echocardiography (TNE) ≤72 h old, during PPHN, were retrospectively studied. Three standard TNE clips were reviewed by two blinded assessors, and infants categorized as Q-RVd if moderate-severe RVd was diagnosed on ≥2 clips. Cardiopulmonary clinical indices at TNE and quantitative RV functional markers were compared between Q-RVd vs. no-RVd groups. Potential quantitative RVd definitions examined by classifying each measurement as "low" or "normal" using published data. Inter-rater agreement for Q-RVd assessed using Kappa statistics.

RESULTS

Mean age at TNE was 25.3 ± 20.4 h with Q-RVd diagnosed in 19(40 %) infants. Q-RVd group demonstrated higher peak oxygen requirements (96 ± 9 % vs. 84 ± 16 %, p < 0.01); however, no clinical parameters at TNE differentiated the groups. Quantitative measures were lower in Q-RVd patients, confirming classification validity. Among tested quantitative definitions, low RV stroke volume was associated with lower systolic blood pressure (41±7 vs. 47±9 mmHg, p = 0.02) and higher shock index (4.02±0.80 vs. 3.44±0.72, p = 0.02). Kappa for Q-RVd was 0.55 (95%CI 0.32-0.77).

CONCLUSIONS

The non-specific nature of clinical markers of RVd in preterm infants with PPHN necessitates echocardiographic diagnosis of RVd. Studies should examine prognostic relevance of RVd and establish outcome-based quantitative definitions in preterm infants.

Relationship between cerebral oxygenation, cardiac output, and blood pressure during transitional period in extremely low gestational age neonates

Objective

To describe the relationship between cerebral oxygenation, cardiac output, arterial blood pressure (BP), and cerebral blood flow velocity in extremely low gestational age neonates (ELGANs) during transition.

Methods

This study comprises secondary analyses from a prospective observational study conducted at a tertiary Neonatal Intensive Care Unit. Recruited ELGANs underwent cerebral saturation (CrSO2) monitoring and serial echocardiography during 72 h from birth. Correlative analyses of CrSO2 and cerebral fractional tissue oxygen extraction (CFTOE) with left (LVO) and right ventricular output (RVO), superior vena cava (SVC) flow, middle cerebral artery blood flow mean velocity (MCA.MV), systolic (SBP), diastolic (DBP), and mean (MBP) BP were conducted.

Results

Fifty ELGANs with median (range) gestational age of 25.9 (23.1-27.9) weeks were recruited. Echocardiography was performed sequentially at a median (range) age 5.0 (3.8-6.6), 17.3 (15.4-19.4), 31.0 (27.0-34.1), and 53.7 (49.3-58.3) hours. RVO, LVO, CrSO2, and SBP increased over time but no changes in MBP, DBP, CFTOE, MCA.MV or SVC flow were noted. A weak correlation was identified between CrSO2 and SBP (r2 = 0.11, p = 0.047) and MBP (r2 = 0.12, p = 0.04) at 17.3 (15.4-19.4) hours. No correlation of either CrSO2 or CFTOE with any measures of blood flow was identified.

Conclusion

There is a weak correlation between measures of cardiac output, BP, and MCA.MV with both CrSO2 and CFTOE in ELGANs during transition. Whether this finding suggests intact cerebral autoregulation requires prospective evaluation in a cohort of sick ELGANs.

Trends in aEEG Cyclicity and Amplitudes During Transition in Extremely Low Gestational Age Infants

AIM

To describe aEEG cyclicity, background pattern, voltage margins and maturation scores in extremely low gestational age neonates (ELGANs) in the first 72 hours.

METHODS

Fifty infants with gestational age (GA) 23⁰ - 27⁶ weeks were prospectively studied. Infants with intraventricular hemorrhage ≦ Grade I and no disorders of transition [persistent pulmonary hypertension, hypotension, pulmonary hemorrhage] belonged to the 'Uncomplicated' group and those with intraventricular hemorrhage > Grade I and/or disorders of transition, to the 'Complicated' group.

RESULTS

Thirty-six infants without opioid exposure were included: 23 with GA 25.9 (23.1-27.7) weeks in the 'Uncomplicated' group and 13 with GA 24.6 (23.3-27.4) weeks in the 'Complicated' group. Cyclicity was more common in the 'Uncomplicated' group [20/ 23 (87%) vs. 7/13 (54%), p=0.045] with more cycles/hour [0.2 (0-0.78) vs. 0.03 (0-67), p=0.036]. Age at appearance of cyclicity were similar [20 (7.7- 40.7) hours in 'Uncomplicated' vs. 23.7 (5.4-60) hours in 'Complicated' group, p=0.8]. In the 'Uncomplicated' group, maturation scores (p=0.02), high (p<0.0001) and low (p=0.03) base voltage increased over time.

CONCLUSION

During the first 72 hours, clinically stable ELGANs without neurological injury demonstrate increased cyclicity compared to those with a complicated course. Maturation score, high and low base voltage increase over time.

Dopamine or norepinephrine for sepsis-related hypotension in preterm infants: a retrospective cohort study

The purpose of this study is to compare the clinical effectiveness of dopamine (DA) versus norepinephrine (NE) as first-line therapy for sepsis-related hypotension in preterm infants. This is a retrospective cohort study over 10 years at two tertiary neonatal units. Preterm infants born < 35 weeks post-menstrual age (PMA), who received DA or NE as primary therapy for hypotension during sepsis, defined as culture-positive or culture-negative infections or necrotizing enterocolitis (NEC), were included. Episode-related mortality (< 7 days from treatment), pre-discharge mortality, and major morbidities among survivors were compared between two groups. Analyses were adjusted using the inverse probability of treatment weighting estimated by propensity score (PS). A total of 156 infants were included, 113 received DA and 43 NE. The mean ± SD PMA at birth and at treatment for the DA and NE groups were 25.8 ± 2.3 vs. 25.2 ± 2.0 weeks and 27.7 ± 3.0 vs. 27.1 ± 2.6 weeks, respectively (p > 0.05). Pre-treatment, the NE group had higher mean airway pressure (14 ± 4 vs. 12 ± 4 cmH₂O), heart rate (185 ± 17 vs. 175 ± 17 beats per minute), and median (IQR) fraction of inspired oxygen [0.67 (0.42, 1.0) vs. 0.52 (0.32, 0.82)] (p < 0.05 for all). After PS adjustment, NE was associated with lower episode-related mortality [adjusted odds ratio (95% CI) 0.55 (0.33, 0.92)], pre-discharge mortality [0.60 (0.37, 0.97)], post-illness new diagnosis of significant neurologic injury [0.32 (0.13, 0.82)], and subsequent occurrence of NEC/sepsis among the survivors [0.34, (0.18, 0.65)].

CONCLUSION

NE may be more effective than DA for management of sepsis-related hypotension among preterm infants. These data provide a rationale for prospective evaluation of these commonly used agents.

WHAT IS KNOWN

•Dopamine is the commonest vasoactive agent used to support blood pressure among preterm infants. •For adult patients, norepinephrine is recommended as the preferred therapy over dopamine for septic shock.

WHAT IS NEW

•This is the first study examining the relative clinical effectiveness of dopamine and norepinephrine as first-line pharmacotherapy for sepsis-related hypotension among preterm infants. •Norepinephrine use may be associated with lower mortality and morbidity than dopamine in preterm infants with sepsis.

Fetal Endoscopic Tracheal Intubation: Modification of the Fetal Endoscopic Tracheal Intubation Procedure to Establish an Airway in a Fetus with a Congenital Cervical Teratoma

INTRODUCTION

FETI is a technique where the fetal airway is secured in-utero via intubation by percutaneous endoscopic fetal tracheoscopy under ultrasound guidance. FETI has been described in large fetal neck masses with anatomical airway compression as a feasible airway management strategy and a potential alternative to an EXIT procedure in select cases.

CASE PRESENTATION

This report describes the use of a modified FETI procedure under continuous fetoscopic and ultrasound guidance, in a fetus with a large cervical teratoma causing airway displacement and compression. Following the FETI procedure, an uncomplicated caesarean section was performed. The endotracheal tube was in place at the time of birth, and a patent airway was confirmed.

CONCLUSION

The modified FETI procedure described in this report represents another technique that can be used to establish an airway in fetuses with challenging upper airway anatomy, potentially mitigating the risks associated with an EXIT procedure.

2% aqueous vs alcohol-based chlorhexidine for skin antisepsis in VLBW neonates undergoing peripheral venipuncture: a non-inferiority trial

OBJECTIVE

To compare 2% aqueous chlorhexidine gluconate (AQC) vs. 2% chlorhexidine gluconate in 70% isopropyl alcohol (ALC) for pre-venipuncture skin antisepsis in very-low-birth-weight neonates (VLBW, birth-weight <1500 grams).

STUDY DESIGN

Double-blind, non-inferiority trial randomized 199 VLBW neonates, age 2-28 days, to receive pre-venipuncture skin preparation using single application of swabstick impregnated with AQC (n = 99) or ALC (n = 100). Skin clearance rate (percentage post-cleansing skin swabs with <15 bacterial colony forming units) with a 10% non-inferiority margin for AQC was primary outcome. Absolute and relative CFU reduction and adverse skin reactions were compared.

RESULTS

AQC's clearance was non-inferior to ALC (91% vs. 88%; 95% CI -6.6%, +12.4%). Median (interquartile range) absolute [61 (16, 110) vs. 63 (18, 100); p = 0.65] and relative [100% (97%, 100%) vs. 100% (99.7%, 100%); p = 0.20] CFU reductions were similar. Neither group experienced any adverse reactions.

CONCLUSION

AQC may provide non-inferior skin disinfection to ALC in VLBW neonates.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT01270776.

Physiology of Low Blood Pressure During the First Day After Birth Among Extremely Preterm Neonates

OBJECTIVE

To investigate the circulatory physiology of hypotension during the first day after birth among stable extremely preterm neonates.

STUDY DESIGN

Case-control study of neonates born at ≤27^6/7 weeks gestational age with hypotension, defined as mean blood pressure in mmHg less than gestational age in weeks for at least 1 hour during the first 24 hours after birth, who underwent comprehensive echocardiography assessment before commencement of cardiovascular drugs. Neonates with hypotension (n = 14) were matched by gestational age and intensity of respiratory support with normotensive neonates (n = 27) who underwent serial echocardiography during the first day after birth, and relatively contemporaneous echocardiography assessments were used for comparison.

RESULTS

Neonates with hypotension had a higher frequency of patent ductus arteriosus ≥1.5 mm (71% vs 15%; P < .001) and ductal size (median diameter, 1.6 mm [IQR, 1.4-2.1] vs 1.0 mm [IQR, 0-1.3]; P = .002), higher echocardiography indices of left ventricular systolic function (mean shortening fraction, 34 ± 7% vs 26 ± 4%; P < .001; mean longitudinal strain, -16 ± 5% vs -14 ± 3%; P = .04; and mean velocity of circumferential fiber shortening, 1.24 ± 0.35 circ/s vs 1.01 ± 0.28 circ/s; P = .03), lower estimates of left ventricular afterload (mean end-systolic wall stress, 20 ± 7 g/cm² vs 30 ± 9 g/cm²; P < .001 and mean arterial elastance, 43 ± 19 mmHg/mL vs 60 ± 22 mmHg/mL; P = .01), without significant difference in stress-velocity index z-score (-0.42 ± 1.60 vs -0.88 ± 1.30; P = .33). Neonates with hypotension had higher rates of any degree of intraventricular hemorrhage (71% vs 22%; P = .006).

CONCLUSIONS

Low blood pressure in otherwise well extremely low gestational age neonates was associated with low systemic afterload and larger patent ductus arteriosus, but not left ventricular dysfunction.

Multicentre prospective observational study exploring the predictive value of functional echocardiographic indices for early identification of preterm neonates at risk of developing chronic pulmonary hypertension secondary to chronic neonatal lung disease

INTRODUCTION

Although chronic pulmonary hypertension (cPH) secondary to chronic neonatal lung disease is associated with increased mortality and respiratory and neurodevelopmental morbidities, late diagnosis (typically ≥36 weeks postmenstrual age, PMA) and the use of qualitative echocardiographic diagnostic criterion (flat interventricular septum in systole) remain significant limitations in clinical care. Our objective in this study is to evaluate the utility of relevant quantitative echocardiographic indices to identify cPH in preterm neonates, early in postnatal course and to develop a diagnostic test based on the best combination of markers.

METHODS AND ANALYSIS

In this ongoing international prospective multicentre observational diagnostic accuracy study, we aim to recruit 350 neonates born <27 weeks PMA and/or birth weight <1000 g and perform echocardiograms in the third week of age and at 32 weeks PMA (early diagnostic assessments, EDA) in addition to the standard diagnostic assessment (SDA) for cPH at 36 weeks PMA. Predefined echocardiographic markers under investigation will be measured at each EDA and examined to create a scoring system to identify neonates who subsequently meet the primary outcome of cPH/death at SDA. Diagnostic test characteristics will be defined for each EDA. Pulmonary artery acceleration time and tricuspid annular plane systolic excursion are the primary markers of interest.

ETHICS AND DISSEMINATION

Ethics approval has been received by the Mount Sinai Hospital Research Ethics Board (REB) (#16-0111-E), Sunnybrook Health Sciences Centre REB (#228-2016), NHS Health Research Authority (IRAS 266498), University of Iowa Human Subjects Office/Institutional Review Board (201903736), Rotunda Hospital Research and Ethics Committee (REC-2019-008), and UBC Children's and Women's REB (H19-02738), and is under review at Boston Children's Hospital Institutional Review Board. Study results will be disseminated to participating families in lay format, presented to the scientific community at paediatric and critical care conferences and published in relevant peer-reviewed journals.

TRAIL REGISTRATION NUMBER

NCT04402645.

Clinical validity of systemic arterial steal among extremely preterm infants with persistent patent ductus arteriosus

OBJECTIVE

Investigate relevance of diastolic flow abnormalities in celiac trunk (aCT) and middle cerebral artery (aMCA) among preterms with persistent hemodynamically significant patent ductus arteriosus (phsPDA, diameter ≥ 1.5 mm, and age ≥ 7 days).

STUDY DESIGN

Five hundred fifteen echocardiograms from 156 neonates born <28 weeks gestation age (GA) were analyzed retrospectively. Infants with aCT or aMCA at any time were compared with the rest. Separate comparisons were performed for aCT and aMCA. Primary outcome was composite of death, chronic lung disease (CLD), or necrotizing enterocolitis ≥ stage 2. Logistic regression was used to adjust for confounders.

RESULT

Mean (SD) weight and GA were 820(214) g and 25.2(1.3) weeks. aMCA, but not aCT, was associated with primary outcome [adjusted odds ratio 2.17, 95% CI: 1.01-4.67] and CLD [2.20 (0.99-4.87)].

CONCLUSION

aMCA may be a valid marker for defining the clinical significance of phsPDA in preterm neonates. aCeT may be of limited value in selecting patients for treatment.

Effect of Phenobarbitone on Amplitude-Integrated Electroencephalography in Neonates with Hypoxic-Ischemic Encephalopathy during Hypothermia

BACKGROUND

Phenobarbitone induces suppression of cerebral electrical activity on amplitude-integrated electroencephalography (aEEG) in neonates with hypoxic-ischemic encephalopathy (HIE); however, its effect during therapeutic hypothermia (TH) has not been well characterized.

OBJECTIVE

To evaluate the effect of phenobarbitone on aEEG in neonates with HIE undergoing TH.

METHODS

Thirty-five neonates born at ≥350 weeks gestational age (GA), who received phenobarbitone as first-line antiepileptic drug during TH for ≥ Sarnat stage II HIE with aEEG recordings were retrospectively studied. Background pattern, upper and lower margin voltages were characterized for a 30-min period before and 30-60 min after phenobarbitone administration. Primary outcome was presence of severely abnormal aEEG pattern after phenobarbitone administration.

RESULTS

Mean (±SD) GA and median birth weight were 38.2 ± 1.9 weeks and 3.1 (2.5-3.9) kg, respectively. Phenobarbitone (10-20 mg/kg), administered at median age 16.8 h, was associated with background pattern worsening in 19/29 (65.5%) cases. Severe background patterns were more prevalent in post- versus pre-phenobarbitone tracings (21/29 [72%] vs. 11/29 [38%]; p = 0.01). Presence of severe pattern versus either continuous normal voltage or discontinuous normal voltage pattern post-phenobarbitone, (20/25 [80%] vs. 3/8 [38%]; p = 0.036) was associated with death or moderate-to-severe injury on MRI brain. Median time to trace recovery, when measurable, was 4 h (45 min-72 h).

CONCLUSIONS

Phenobarbitone induces significant suppression on aEEG in infants with HIE undergoing TH. Development of severe aEEG background patterns after phenobarbitone may unmask a population at greater risk of abnormal outcome.

Combined Multimodal Cerebral Monitoring and Focused Hemodynamic Assessment in the First 72 h in Extremely Low Gestational Age Infants

BACKGROUND

Characteristic changes in cerebral saturation (CrSO2), amplitude-integrated electroencephalography (aEEG), and echocardiography (ECHO) may be associated with intraventricular hemorrhage (IVH); however, the feasibility of their combined application is not known.

OBJECTIVE

The aim of this work was to investigate the feasibility and safety of combined multimodal cerebral and hemodynamic monitoring in extremely low gestational age (ELGA) infants in the first 72 h after birth.

METHODS

In this prospective -observational study of 50 infants born between 23 + 0 and 27 + 6 weeks gestation, we measured CrSO2 and aEEG, starting <8 h until 72 h of age. Sequential echocardiography and head ultrasound were performed at 4-8, 12-18, 24-30, and 48-60 h of age. The primary outcome was feasibility of multimodal monitoring, defined as >75% of the subjects satisfying at least 3/4 criteria: (a) CrSO2 and (b) aEEG monitoring each for >75% of the time, and (c) at least 2 out of 4 ECHO and (d) head ultrasounds (at least one by age 24 h). Adverse reactions to sensors, desaturation, and bradycardia during ultrasound studies were recorded.

RESULTS

Fifty infants were enrolled over 14 months. Multimodal monitoring was feasible in 49 (98%) infants. Forty-one (82%) infants fulfilled all 4 criteria. Mild erythema below CrSO2 sensors lasting 3-8 h without skin breakdown was noted in 8/50 subjects (16%). Desaturation was noted during 17/197 (8.6%) of the ultrasound studies. In total, 26/50 (52%) infants developed IVH (grade I/II, n = 22; grade III/IV, n = 4).

CONCLUSION

Multimodal monitoring is feasible, safe, and well tolerated in ELGA infants in the first 72 h after birth.

Implementation of amplitude-integrated electroencephalography in tertiary Canadian Neonatal Intensive Care Units-a longitudinal study

Aim

To investigate the implementation of amplitude-integrated electroencephalography (aEEG) as bedside monitoring tool of cerebral function in tertiary Canadian Neonatal Intensive Care Units (NICU) over the past decade.

Methods

Longitudinal study consisting of online surveys of neonatologists on the use of aEEG in 2009 and 2018.

Results

The response rate to the survey was 72 of 149 (49%) in 2009 and 18 of 30 (60%) in 2018, respectively. aEEG has been implemented in almost all (2009: 62.5%; 2018: 94%) tertiary Canadian NICUs. Two-thirds (2009: 67%; 2018: 71%) of the respondents considered information from aEEG tracing helpful in clinical practice. The main indications for aEEG were term neonates with hypoxic ischemic encephalopathy (2009 and 2018: 76%) and seizure detection/surveillance (2009: 88%; 2018: 94%). Teaching on aEEG has been implemented for neonatologists (2018: 100%) and health care providers (2018: 50%) in tertiary Canadian NICUs but there is a lack of standardization of training. Use of aEEG in preterm neonates (2009: 37%, 2018: 33%) and application of aEEG in research (18% reported occasional use) is less common.

Conclusion

aEEG is well established in tertiary Canadian NICUs to monitor cerebral function and detect seizure activity. There is a need to develop formalized aEEG training programs and methods to assess competence. Further implementation of aEEG in preterm neonates and research is desirable.

Household food insecurity is associated with low interferon-gamma levels in pregnant Indian women

SETTING

Over 20% of tuberculosis (TB) cases during pregnancy occur in India.

OBJECTIVE

To determine the association between household food insecurity and interferon-gamma (IFN-γ) levels in pregnancy.

DESIGN

Pregnant women in India were administered the Household Food Insecurity Access Scale (HFIAS) questionnaire and underwent an IFN-γ release assay. Logistic regression was used to identify factors associated with food insecurity.

RESULTS

Of 538 women, 60 (11%) had household food insecurity, 47 (78%) of which were moderate or severe food insecure. After mitogen stimulation, moderate or severe food insecure women had a median IFN-γ concentration of 4.2 IU/ml (IQR 2.2-9.8) vs. 8.4 IU/ml (IQR 3.0-10) in women with no or mild food insecurity (P = 0.03). In multivariate analysis, higher IFN-γ concentrations were associated with human immunodeficiency virus infection (OR 1.3, 95%CI 0.51-2.1, P = 0.001), and inversely associated with moderate or severe food insecurity (OR -1.6, 95%CI -2.9 to -0.27, P = 0.02) and the number of adults in the household (OR -0.08, 95%CI -0.16 to -0.01, P = 0.03). There was no association between food insecurity and IFN-γ response to Mycobacterium tuberculosis antigen.

CONCLUSION

Food insecurity in pregnancy is associated with low IFN-γ levels. There was no association between food insecurity and IFN-γ response to M. tuberculosis antigen, but our study was underpowered to detect this outcome.

Tribocatalytic behaviour of a TiO2 atmospheric plasma spray (APS) coating in the presence of the friction modifier MoDTC: a parametric study

Recent engine design and emission trends have led to the commercial use of Atmospheric Plasma Spray (APS) coatings for cylinder liner applications like the TiO₂ APS coating. It was shown in our previous work that this type of coating showed better friction results compared to steel lubricated with MoDTC. To further investigate this feature, a parametric study was carried out involving the effect of MoDTC concentration, test temperature, Hertzian contact pressure and the change of counterpart materials from steel balls to ceramic balls (Al₂O₃ and ZrO₂). Ball-on-flat tribotests were carried out on a reciprocating (ball-on-flat) tribometer lubricated with base oil containing MoDTC. Results show that for all the test conditions used including the concentration of MoDTC, test temperature and the contact pressure, lower friction and wear is observed for the TiO₂ APS coating compared to reference steel. To explain the low friction behavior, tribofilm compositions were investigated and it was observed that MoS₂ is always formed in the case of TiO₂ APS with no oxysulphide species. For the reference steel, MoO_xS_y species are mainly detected in the tribofilms. XPS analyses performed on TiO₂ APS flats when the counterpart material was changed from steel balls to ceramic balls suggested the formation of MoS₂ (Mo in +iv oxidation state) and Mo–C (Mo in +iv or +ii oxidation state) species with a negligible amount of MoO₃ (Mo in +vi oxidation state). It was also shown that a significant amount of molybdenum atoms inside the tribofilm, originating from MoDTC (Mo in +v oxidation state) were reduced in the tribological contact. A mechanism for the decomposition of MoDTC on the basis of tribocatalytic behaviour hypothesized in our previous work was proposed and discussed.

Tribocatalytic behaviour of TiO₂ APS coatings in presence of MoDTC additive under boundary lubrication conditions – decomposition mechanism

Outcomes associated with early removal versus retention of peripherally inserted central catheters after diagnosis of catheter-associated infections in neonates

OBJECTIVE

To compare clinical outcomes and hospital resource utilization of infants who had peripherally inserted central catheters removed early versus retained following diagnosis of central line-associated bloodstream infection.

STUDY DESIGN

In a single centre retrospective cohort study, we compared outcomes of infants who had peripherally inserted central catheters removed early versus retained after diagnosis of central line-associated bloodstream infection. Mortality, cardio-respiratory deterioration, use of blood products and antibiotics were compared between groups.

RESULTS

Over a 10-year period, of the 119 eligible infants, 38 had peripherally inserted central catheters removed early and 81 had catheters retained after diagnosis of central line-associated bloodstream infection. Baseline demographics, illness severity at onset of sepsis and distribution of organisms were similar between the groups. Infants in "catheter-retained" group required longer antibiotic usage (17 ± 9 versus 13 ± 6 days; p = 0.025) and more frequent sequential positive blood cultures [31/81 (47%) versus 8/38 (22%), p = 0.014). Infants with Gram-negative bacteremia demonstrated higher mortality when catheters were retained [43% (9/21) versus 7% (1/14); p = 0.028].

CONCLUSIONS

Retaining peripherally inserted central catheters after diagnosis of central line-associated bloodstream infection was associated with longer duration of bacteremia and prolonged exposure to systemic antibiotics as well as increased mortality in Gram-negative bacteremia.

Impact of maternal hepatitis B virus coinfection on mother-to-child transmission of HIV

OBJECTIVES

Despite high hepatitis B virus (HBV) endemicity in various resource-limited settings (RLSs), the impact of maternal HIV/HBV coinfection on infant health outcomes has not been defined. We aimed to assess the prevalence of HBV coinfection among HIV-infected pregnant women and its impact on HIV transmission and infant mortality.

METHODS

In this study, the seroprevalence of HBV coinfection was determined among HIV-infected pregnant women enrolled in the Six-Week Extended-Dose Nevirapine (SWEN) India trial. The impact of maternal HIV/HBV coinfection on mother-to-child transmission (MTCT) of HIV and infant mortality was assessed using univariate and multivariate logistic regression analysis.

RESULTS

Among 689 HIV-infected pregnant Indian women, 32 (4.6%) had HBV coinfection [95% confidence interval (CI) 3.4%, 5.3%]. HBV DNA was detectable in 18 (64%) of 28 HIV/HBV-coinfected women; the median HBV viral load was 155 copies/mL [interquartile range (IQR) < 51-6741 copies/mL]. Maternal HIV/HBV coinfection did not increase HIV transmission risk [adjusted odds ratio (aOR) 1.06; 95% CI 0.30, 3.66; P = 0.93]. Increased odds of all-cause infant mortality was noted (aOR 3.12; 95% CI 0.67, 14.57; P = 0.15), but was not statistically significant.

CONCLUSIONS

The prevalence of active maternal HBV coinfection in HIV-infected pregnant women in India was 4.6%. HIV/HBV coinfection was not independently associated with HIV transmission.

Peripherally inserted central catheter tip position and risk of associated complications in neonates

OBJECTIVE

To characterize the relationship between peripherally inserted central catheters (PICC) tip positions and associated complications in neonates.

STUDY DESIGN

Catheter tip position for 319 infants was classified into superior vena cava (SVC, n=131), inferior vena cava (IVC, n=72), brachiocephalic (BC, n=59), midclavicular (MC, n=49) or iliac. Duration of catheter stay and complication profile was compared between central (SVC/IVC) vs non-central PICC, and between SVC vs IVC, SVC vs BC and SVC vs MC. Kaplan-Meier survival analysis and regression models were used.

RESULT

Overall length of catheter stay was similar between central and non-central group. Non-central catheters (n=116) had higher complication rates (47 vs 29%; P=0.001), non-elective removals (45 vs 27%; P=0.002) and shorter time to complication (6.2 vs 11.4 days; P=0.043). This difference was primarily due to the complications encountered in MC group, which had the highest rate of infiltration (P<0.001) and mechanical complications while outcomes were similar among other subgroups. Interestingly, catheter survival probability was similar in all groups for first 4 days. Rate and types of blood stream infections were not related to catheter tip position.

CONCLUSION

Non-central PICCs are associated with higher rates of infiltration and mechanical complications when the tip is in MC region. BC catheters may have comparable outcomes to SVC in neonates. A careful risk-benefit analysis is warranted when MC catheters are used in neonates.

Standardization of fungal polymerase chain reaction for the early diagnosis of invasive fungal infection

BACKGROUND

An early initiation of antifungal therapy in invasive fungal infections (IFIs) is critical in reducing the high mortality rate. Current diagnosis of fungal infection relies on microscopy, culture, antigen, antibody specific tests and histological diagnosis. However, these tests either lack sensitivity or specificity. There is thus the need for a rapid, specific and accurate diagnostic method.

OBJECTIVE

The aim of our study was to establish PCR for the rapid detection of Candida and Aspergillus species in clinical specimens with improved sensitivity and specificity.

MATERIALS AND METHODS

A total of 71 proven cases of IFI (confirmed by culture) were collected. A total of 15 healthy, 15 patients suffering from bacterial sepsis and 15 patients with HIV, HBV viral infections were included as controls. Clinical specimens were subjected to a standardized nested amplification to produce Round I (504 bp) and Round II (150 bp) amplicons. Restriction digestion was performed on these products for further identification.

RESULTS

Analytical sensitivity was determined using 10⁶-10 CFU/ml of cell suspension. The lower detection limit of the assay was 10 CFU/ml of blood. This test was 100% sensitive and specific with a positive predictive value of 100% and a negative predictive value of 96.7%.

CONCLUSION

The assay was found to be effective for the rapid detection of Candida and Aspergillus in clinical specimens.

Development and validation of a HPTLC method for Estimation of Duloxetine Hydrochloride in Bulk Drug and in Tablet Dosage Form

Duloxetine hydrochloride is a potent dual reuptake inhibitor of serotonin and norepinephrine used to treat major depressive disorders. The present work describes a simple, precise and accurate HPTLC method for its estimation as bulk and in tablet dosage form. The chromatographic separation was carried out on precoated silica gel 60 F254 aluminium plates using mixture of chloroform:methanol (8:1 v/v) as mobile phase and densitometric evaluation of spots was carried out at 235 nm using Camag TLC Scanner-3 with win CAT 1.3.4 version software. The experimental parameters like band size of the spot applied, chamber saturation time, solvent front migration, slit width etc. were critically studied and optimum conditions were evolved. The drug was satisfactorily resolved with Rf value 0.11+/-0.01. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity (40-200 ng/spot), precision (intra-day RSD 0.46-0.75%, inter-day RSD 0.46-1.59%), accuracy (98.72+/-0.20) and specificity according to ICH guidelines. The proposed method can analyse ten or more formulation units simultaneously on a single plate and provides a faster and cost-effective quality control tool for routine analysis of duloxetine hydrochloride as bulk drug and in tablet formulation.

Genetic Approaches Identify Differential Roles for α4β2*Nicotinic Receptors in Acute Models of Antinociception in Mice

The effects of nicotine on the tail-flick and hot-plate tests were determined to identify nicotinic receptor subtypes responsible for spinally and supraspinally mediated nicotine analgesia in knockin mice expressing hypersensitive alpha(4) nicotinic receptors (L9'S), in seven inbred mouse strains (C57BL/6, DBA/2, A/2, CBA/2, BALB/cByJ, C3H/HeJ, and 129/SvEv), and in two F1 hybrids (B6CBAF1 and B6D2F1). L9'S heterozygotes were approximately 6-fold more sensitive to the antinociceptive effects of nicotine than the wild-type controls in the hot-plate test but not in the tail-flick assay. Large differences in the effects of nicotine were also observed with both tests for the seven mouse strains. A/J and 129 mice were 6- to 8-fold more sensitive than CBA and BALB mice. In addition, B6CBAF1 hybrid mice were even less sensitive than CBA mice. Nicotinic binding sites were measured in three spinal cord regions and the hindbrain of the inbred strains. Significant differences in cytisine-sensitive, high affinity [(125)I]epibatidine binding site levels (alpha(4)beta(2)(*) subtypes), but not in (125)I-alpha-bungarotoxin binding (alpha(7)(*) subtypes), were observed. Significant negative correlations between cytisine-sensitive [(125)I]epibatidine binding and nicotine ED(50) for both tests were noted. Our results indicate that alpha(4)beta(2)(*) acetylcholine nicotinic receptors (nAChR) are important in mediating nicotine analgesia in supraspinal responses, while also showing that alpha(4)beta(2)(*)-nAChR and at least one other nAChR subtype appear to modulate spinal actions.

Soleus motor neuron excitability before and after standing

H-reflexes have been used to assess the effect of various postures on the excitability of the soleus motor neuronal pool. The purpose of this study was to determine if the excitability of the motor neuron pool, measured via H-reflexes in a seated position, change after a standing protocol in able-bodied individuals. We hypothesized that the excitability of the motor neuronal pool is minimally affected by the standing protocol leading to a reproducible H-reflex. Ten healthy individuals (height = 69.05+/-2.27 inches, weight = 161.7+/-22.44 lbs, age = 27.7+/-7.0 years) participated in the study. Soleus H-reflex recruitment curves were established before and after a standing protocol in a seated position. The standing protocol involved 12 minutes of active upright standing interspersed with 10 minutes of relaxed passive standing in a standing frame, similar to a protocol currently used for spinal cord injured subjects. The maximum M-waves and H-reflex amplitudes were not systematically changed before and after standing. There was also a strong agreement between the H-reflexes and M-waves measured before and after standing (ICC = 0. 99 and .96, respectively). We conclude that the H-reflexes measured in this study were reproducible, indicating that standing had no long lasting effect on the motor neuronal pool excitability. The findings support that the method discussed in this report is appropriate to assess the effects of electrically induced standing on motor neuron pool excitability in individuals with spasticity from spinal cord injury.

Using active management of labor and vaginal birth after previous cesarean delivery to lower cesarean delivery rates: aA 10-year experience

OBJECTIVE

Our objective was to analyze the statistics on cesarean delivery rates and the factors that have led to a reduction in these rates.

STUDY DESIGN

A retrospective analysis was done of delivery statistics from a 10-year period, January 1, 1989, to December 31, 1998. We investigated the changes made in the methods of delivery during the study period. The data were divided into 1-year periods and analyzed by chi(2) tables.

RESULTS

The overall cesarean delivery rate decreased from 16.59% to 10.92%; the primary cesarean delivery rate decreased from 9.22% to 7.11% and the repeated cesarean delivery rate from 7.37% to 3.81%. All these decreases were statistically significant. An increase in the rate of active management of labor by increasing oxytocin use and encouraging a trial of labor after previous cesarean delivery was also statistically significant. No changes in the outcome were observed in terms of neonatal morbidity and mortality rates.

CONCLUSION

We found that our working plan for management of labor and delivery yielded and maintained a successful decline in the cesarean delivery rates without any negative effect on neonatal or maternal mortality rates. This low rate was maintained for a 10-year period.

Prenatal diagnosis of fetal abdominal lymphangioma by ultrasonography

We present a case of abdominal lymphangioma in a fetus together with a review of the literature. Diagnosis was made at 20 weeks' gestation by antenatal ultrasonography. In keeping with other reports, the lesion was located on the left and serial ultrasonography demonstrated rapid growth with extension into the lower extremity.

Point mutant mice with hypersensitive alpha 4 nicotinic receptors show dopaminergic deficits and increased anxiety

Knock-in mice were generated that harbored a leucine-to-serine mutation in the alpha4 nicotinic receptor near the gate in the channel pore. Mice with intact expression of this hypersensitive receptor display dominant neonatal lethality. These mice have a severe deficit of dopaminergic neurons in the substantia nigra, possibly because the hypersensitive receptors are continuously activated by normal extracellular choline concentrations. A strain that retains the neo selection cassette in an intron has reduced expression of the hypersensitive receptor and is viable and fertile. The viable mice display increased anxiety, poor motor learning, excessive ambulation that is eliminated by very low levels of nicotine, and a reduction of nigrostriatal dopaminergic function upon aging. These knock-in mice provide useful insights into the pathophysiology of sustained nicotinic receptor activation and may provide a model for Parkinson's disease.

Failure of autoresuscitation in weanling mice: significance of cardiac glycogen and heart rate regulation

"Autoresuscitation" (AR) is the spontaneous recovery from hypoxic apnea by gasping. We examined aspects of heart function in two situations: 1) the maturationally acquired failure of AR that is characteristic of SWR, but not BALB/c, weanling mice and 2) AR failure in BALB/c mice induced by repeated exposures to anoxia. We determined maturational changes in heart and liver glycogen. Unlike liver glycogen levels, heart glycogen levels in SWR mice differed from those in BALB/c mice. They were consistently much lower throughout maturation and reached a nadir during the brief period when SWR weanling mice are vulnerable to AR failure. Also, rate of cardiac glycogen utilization in vulnerable SWR mice was lower than that of same-aged BALB/c mice and was nil during the latter one-half of the gasping stage when heart function is critical for AR success. Therefore, because glycogen utilization reflects cardiac work, heart failure could explain AR failure in SWR weanlings. Additionally, the increase in hypoxic heart rate that occurs with maturation is developmentally delayed in SWR mice, and this may contribute to their AR failure. Cardiac glycogen was not fully depleted in BALB/c mice during repeated anoxic exposures, indicating other reasons for AR failure. We view these findings as a potential model for the age-related peak in incidence of sudden infant death syndrome.

Pyrexia of unknown origin, the age-old dilemma

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Obsessive-compulsive symptoms in chronic schizophrenia: a new idea or an old belief?

Obsessive-compulsive (OC) symptoms during the course of schizophrenia have been reported, yet the incidence and significance of this finding is still unclear. This study was undertaken to determine the prevalence of OC symptoms among chronic schizophrenic patients and to systematically identify them. 101 patients satisfying DSM-IV diagnosis of chronic schizophrenia were assessed for OC symptoms. All patients were also rated on the Yale-Brown Obsessive Compulsive Scale for the severity of their symptoms. The study revealed that 26.7% of the chronic schizophrenic patients had significant OC symptoms with a high prevalence in the age group below 35 years. OC symptoms were more severe in patients with duration of illness more than 5 years. The OC symptoms were more prevalent among paranoid schizophrenics with the frequent obsessions being that of contamination, sexual and aggressive thoughts and frequent compulsion was need to ask or confess.

Channel gating governed symmetrically by conserved leucine residues in the M2 domain of nicotinic receptors

In nicotinic acetylcholine receptors (nAChR), as well as glycine, GABAA (gamma-aminobutyric acid), serotonin (5-HT3), and GluCl glutamate receptors, a leucine residue at the approximate midpoint of the M2 transmembrane domain (the 9' position) is conserved across most known subunits. Structural data for the nAChR suggest that the Leu 9' residues occupy a 'kink' in each of the five M2 helices and point into the closed channel; in the opening step, the M2 helices rotate so that Leu 9' side chains no longer occlude the conduction pathway. Mutation of Leu 9' to one of several other residues slows desensitization and increases sensitivity to agonist. We have exploited the alpha 2 beta gamma delta stoichiometry of muscle nAChR to express receptors with ms* = 0 to 5 Leu 9'Ser mutated subunits. Strikingly, each Leu 9'Ser mutation shifts the dose-response relation for ACh to the left by approximately 10-fold; a nAChR with ms* = 4 is 10(4)-fold more sensitive than the wild type. The results suggest that each of the five Leu 9' residues participates independently and symmetrically in a key step in the structural transition between the closed and open states.

DMSO resolves certain compressions and signal dropouts in fluorescent dye labeled primer-based DNA sequencing reactions

Automated base calling algorithms are more sensitive to the quality of the DNA sequencing data than are the labor intensive visual methods of base calling. To improve this quality, data from DNA sequencing reactions have been compared in order to determine the effects of the inclusion of dimethyl sulfoxide (DMSO). Inclusion of 10% DMSO into the reaction cocktail resolves at least one type of sequence compression. This compression may be due to the lack of ability in T7 DNA polymerase to read through certain sequences correctly. The poor quality of these data is seen as radioactive bands or fluorescent signal peaks that have an abnormal alignment, either in the wrong order or as single bands/peaks. The inclusion of DMSO also resolves sequences where the peak signal is absent or severely diminished, leading to a "gap" in the chromatogram profile. DMSO is better than deaza-dITP for resolving certain compressions. Addition of DMSO is a cheaper and more efficient method for high-throughput DNA sequencing than repeating reactions with base analogs.

Organization, sequence, and function of 34.5 kb of genomic DNA encompassing several murine T-cell receptor alpha/delta variable gene segments

A cosmid-bearing murine genomic DNA, encompassing several T-cell receptor variable alpha/delta gene segments, has been sequenced using shotgun DNA cloning methodology coupled with fluorescence-based high-through-put DNA sequencing technology. This region, spanning 34.5 kb, contains a pseudogene V alpha gene segment (psi V alpha 16.1), a V delta gene segment (V delta 2), and a variable gene segment that has been reported to be expressed with both C alpha (V alpha 6) and C delta (V delta 3). Therefore, this cosmid is the ideal vehicle for examining the possible control sequences that may be involved in determining whether a V gene segment associates with either C alpha or C delta. Polymerase chain reaction experiments demonstrate that the two functional variable gene segments (V delta and V alpha/delta) are expressed individually with both C alpha and C delta genes as mRNA, indicating a permissiveness in their expression patterns. In addition, a variety of genomic sequence-related features have been identified.

The human T-cell receptor TCRAC/TCRDC (C alpha/C delta) region: organization, sequence, and evolution of 97.6 kb of DNA

We sequenced and analyzed 97.6 kb of new DNA sequence containing the human TCRAC (C alpha) and TCRDC (C delta) genes as well as the TCRDV3 (V delta 3) and 61 different TCRAJ (J alpha) gene segments and compared its organization and structure to the previously described mouse T-cell receptor TCRAC/TCRDC (C alpha/C delta) region. A comprehensive nomenclature, consistent with the IUIS nomenclature committee recommendations, for both human and mouse TCRAJ gene segments is presented. In the human sequence, we identified 20 new TCRAJ gene segments and obtained the germline sequence for 23 additional TCRAJ gene segments known from cDNA clones. Using the sequence data obtained from the human TCRAC/TCRDC region, we have extended a polymerase chain reaction-based assay to test for the expression of the individual TCRAJ gene segments. At least five TCRAJ pseudogene segments were identified by sequence criteria. Like the murine TCRAC/TCRDC sequence, this sequence contains a high level of coding sequence, with over 6.6% of the total sequence being transcribed. Comparison of the human sequence with the previously reported mouse DNA sequence reveals homologous counterparts for the variable and joining (J) gene segments and both constant genes. Eleven new J pseudogene segments have been identified in the mouse TCRAC/TCRDC sequence through the use of human and mouse sequence comparisons. In terms of structure and organization, this region of the human and mouse genome appears to be remarkably conserved.

Sequence length and error analysis of Sequenase and automated Taq cycle sequencing methods

We have examined DNA sequence error as a function of length using both a manual method of performing reactions with Sequenase and an automated Taq cycle sequencing method. DNA fragments from both methods were separated and analyzed on a sequencer. To determine the sequence of a cosmid insert (35.3 kb), 379 sequences were obtained from a manual Sequenase method, and 354 sequences were obtained from a Taq cycle sequencing method as performed on an automated robotic workstation and sequenced on an automated fluorescent sequencer. A highly redundant consensus of these sequences was obtained and aligned with the individual sequences to determine sequence error over the length of each sequence. The results of this study indicate that error is about 1% per position over the first 350 nucleotides, but increases thereafter to about 17% at 500 nucleotides. This pattern of accuracy was nearly equivalent for manual Sequenase methods and automated Taq cycle sequencing methods. The potential of these methods in large-scale DNA sequencing projects is discussed.