A Bifunctional Δ12,Δ15-Desaturase from Acanthamoeba castellanii Directs the Synthesis of Highly Unusual n-1 Series Unsaturated Fatty Acids

The free-living soil protozoon Acanthamoeba castellanii synthesizes a range of polyunsaturated fatty acids, the balance of which can be altered by environmental changes. We have isolated and functionally characterized in yeast a microsomal desaturase from A. castellanii, which catalyzes the sequential conversion of C(16) and C(18) Delta9-monounsaturated fatty acids to di- and tri-unsaturated forms. In the case of C(16) substrates, this bifunctional A. castellanii Delta12,Delta15-desaturase generated a highly unusual fatty acid, hexadecatrienoic acid (16:3Delta(9,12,15)(n-1)). The identification of a desaturase, which can catalyze the insertion of a double bond between the terminal two carbons of a fatty acid represents a new addition to desaturase functionality and plasticity. We have also co-expressed in yeast the A. castellanii bifunctional Delta12,Delta15-desaturase with a microsomal Delta6-desaturase, resulting in the synthesis of the highly unsaturated C(16) fatty acid hexadecatetraenoic acid (16:4Delta(6,9,12,15)(n-1)), previously only reported in marine microorganisms. Our work therefore demonstrates the feasibility of the heterologous synthesis of polyunsaturated fatty acids of the n-1 series. The presence of a bifunctional Delta12,Delta15-desaturase in A. castellanii is also considered with reference to the evolution of desaturases and the lineage of this protist.

A stage of change approach to reducing occupational ill health

OBJECTIVE

Interventions targeted by stage of change have been shown to improve the efficacy of public health promotion initiatives in areas such as smoking cessation, alcohol reduction, and mammography screening. Targeted interventions are designed to tackle the key attitudes, beliefs, and intentions that underpin an individual's health-related behavior. Work-related ill health is an increasingly serious issue, the most common cause of which in both the UK and the US is musculoskeletal disorders. This study examined whether the stage approach could be applied to workplace interventions aimed at improving occupational health.

METHOD

A total of 24 multi-component occupational interventions aimed at reducing musculoskeletal disorders were monitored over a period of 4-6 months. In half of these cases, approaches were targeted according to workers' stage of change.

RESULTS

Targeted interventions were found to be significantly more effective in promoting risk awareness and desired behavior change among workers. Significant reductions were also found in self-reported musculoskeletal discomfort among workers having received targeted interventions. No significant differences were found in self-reported musculoskeletal discomfort among workers following standard interventions.

CONCLUSION

Stage-matched approaches may offer scope for substantially improving the efficacy of occupational health and safety interventions by increasing the uptake, implementation, and maintenance of risk-reducing measures.

Identification of Primula "front-end" desaturases with distinct n-6 or n-3 substrate preferences

cDNA clones encoding cytochrome b(5) fusion desaturases were isolated from Primula cortusoides L. and Primula luteola Ruprecht, species previously shown to preferentially accumulate either n-6 or n-3 Delta6-desaturated fatty acids, respectively. Functional characterisation of these desaturases in yeast revealed that the recombinant Primula enzymes displayed substrate preferences, resulting in the predominant synthesis of either gamma-linolenic acid (n-6) or stearidonic acid (n-3). Independent expression of the two Primula desaturases in transgenic Arabidopsis thaliana confirmed these results, with gamma-linolenic acid and stearidonic acid accumulating in both leaf and seed tissues to different levels, depending on the substrate specificity of the desaturase. Targeted lipid analysis of transgenic Arabidopsis lines revealed the presence of Delta6-desaturated fatty acids in the acyl-CoA pools of leaf but not seed tissue. The implications for the transgenic synthesis of C(20) polyunsaturated fatty acids via the elongation of Delta6-desaturated fatty acids are discussed, as is the potential of using Primula desaturases in the synthesis of C(18) n-3 polyunsaturated fatty acids such as stearidonic acid.

The alternative pathway C20 Delta8-desaturase from the non-photosynthetic organism Acanthamoeba castellanii is an atypical cytochrome b5-fusion desaturase

A cDNA encoding a C20 Delta8-desaturase was isolated from the free-living soil amoeba, Acanthamoeba castellanii and functionally characterised by heterologous expression. The open reading frame of the A. castellanii C20 Delta8-desaturase showed similarity to other microsomal front-end desaturases, but the N-terminal domain contained a variant form of the conserved heme-binding motif in which H-P-G-G is replaced by H-P-A-G. Co-expression of the A. castellani Delta8-desaturase with the Isochrysis galbana Delta9-elongase in transgenic Arabidopsis plants confirmed the activity observed in yeast and its role in the alternative pathway for C20 polyunsaturated fatty acid synthesis. Acyl-CoA profiles of these transgenic plants revealed an unexpected accumulation of C20 fatty acids in the acyl-CoA pool. This is the first report of an alternative pathway C20 Delta8-desaturase from a non-photosynthetic organism, and also the first report of a front-end desaturase lacking the canonical cytochrome b5 domain.

Antioxidants for preventing pre-eclampsia

BACKGROUND

Oxidative stress has been proposed as a key factor involved in the development of pre-eclampsia. Supplementing women with antioxidants during pregnancy may help to counteract oxidative stress and thereby prevent or delay the onset of pre-eclampsia.

OBJECTIVES

To determine the effectiveness and safety of any antioxidant supplementation during pregnancy and the risk of developing pre-eclampsia and its related complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (June 2004) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2004).

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing one or more antioxidants with either placebo or no antioxidants during pregnancy for the prevention of pre-eclampsia, and trials comparing one or more antioxidants with another, or with other interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, data extraction and trial quality. Data were double-entered into the Review Manager software.

MAIN RESULTS

Seven trials involving 6082 women are included in this review. The largest trial (5021 women) was quasi-random and only three of the seven included trials were rated high quality. Supplementing women with any antioxidants during pregnancy compared with control or placebo was associated with a 39% reduction in the risk of pre-eclampsia (relative risk (RR) 0.61, 95% confidence intervals (CI) 0.50 to 0.75, seven trials, 6082 women). Women receiving antioxidants compared with control or placebo also had a reduced risk of having a small-for-gestational-age infant (RR 0.64, 95% CI 0.47 to 0.87, three trials, 634 women), their infants had a greater mean birthweight (weighted mean difference 91.83 g, 95% CI 11.55 to 172.11, three trials, 451 women), but they were more likely to give birth preterm (RR 1.38, 95% CI 1.04 to 1.82, three trials, 583 women). There were insufficient data for reliable conclusions about possible effects on any other outcomes.

AUTHORS' CONCLUSIONS

These results should be interpreted with caution, as most of the data come from poor quality studies. Nevertheless, antioxidant supplementation seems to reduce the risk of pre-eclampsia. There also appears to be a reduction in the risk of having a small-for-gestational-age baby associated with antioxidants, although there is an increase in the risk of preterm birth. Several large trials are ongoing, and the results of these are needed before antioxidants can be recommended for clinical practice.

Rapid simultaneous measurement of multiple cytokines using 100 microl sample volumes--association with neonatal sepsis

Early diagnosis of neonatal infection has proved problematic due to the inadequacy of currently available laboratory tests. Neonatal sepsis is associated with an increase in plasma-derived cytokine levels, but an increase of a single cytokine cannot identify neonatal sepsis specifically and multiple cytokine levels are required. The time constraints and relatively large volume of plasma required to measure multiple cytokines from newborn infants by conventional enzyme-linked immunosorbent assay (ELISA) techniques is prohibitive. We therefore applied cytometric bead array (CBA) technology for simultaneous measurement of multiple cytokines from a group of 18 term neonates with infection confirmed by culture and a control group. 'Normal' ranges were established for each cytokine from 1-7-, 8-14- and 15-21-day-old newborns. There was no significant change in the levels of cytokines from infants in different control age groups, suggesting that basal cytokine levels are unchanged in the first 3 weeks of life. In the patient groups, however, there was a significant difference in several cytokines between the different age groups. Interleukin (IL)-6, IL-10 and IL-12 were increased significantly in the 1-7-day-old patient group compared to either the 8-14 and 15-21 age group, suggesting that infection in utero is associated with increased levels of these cytokines compared to infection acquired following birth. When individual patient cytokine levels were compared to normal control reference ranges, two patients failed to show significant elevation of any cytokine tested. All other patients showed elevated levels of between one and nine cytokines tested (mean of 4.6). There was no correlation between elevated cytokine levels and types of infective organism or patient age. In conclusion, neonatal sepsis is associated with the elevation of multiple plasma cytokines. The use of CBA kits is a rapid, easy, low sample volume and sensitive method to measure multiple plasma cytokines.

Expression profiling of the response of Arabidopsis thaliana to methanol stimulation

In order to obtain information about the metabolism of methanol in plants, gene expression in response to methanol stimulation was analysed in leaves of Arabidopsis thaliana through the use of a 26,090 element oligonucleotide microarray. Following confirmation of data and the application of selection criteria, a total of 484 (1.9%) transcripts were shown to be regulated in response to a 10% methanol application. Samples were taken at 1, 24 and 72 h. Of the total identified transcripts, only 20 were shared between all three time points of which only two were down-regulated. Based on functional category analysis of these genes, at 1 h, the largest categories were metabolism, cell communication/signal transduction processes, defence genes associated with transcription and aspects of RNA processing; a few related to cell division and growth; but none were associated with photosynthesis. At 24 and 72 h, the number and overall proportion of regulated transcripts associated with metabolism increased further. Direct measurement of anthocyanin and flavonoid content confirmed that methanol-regulated transcripts corresponded to flavonoid pathways. Within the functional class metabolism, genes encoding detoxification proteins represented by far the most strongly regulated group. These included, cytochrome P450's, glucosyl transferases and members of the ABC transporter family. It is concluded that exposure to methanol affects the expression of hundreds of genes and that multiple detoxification and signalling pathways are activated.

Multiple leucocyte activation markers to detect neonatal infection

Diagnosis of congenital or neonatal infection is often based on clinical signs. However, clinical symptoms of infections may not be specific, and for this reason early diagnosis is often determined on results of laboratory tests, which may not currently be adequate. A more reliable method of detection of infection may be the demonstration of activated lymphocytes, which can be conducted rapidly and before the isolation of the infected organism. We have shown that detection of up-regulation of CD45RO, an activated/memory isoform of CD45 present on T cells, provides a reasonably sensitive screening test for neonatal infection. We also showed that dual expression of CD45RA/CD45RO was up-regulated early during the infective process in neonates with documented infection. However, other leucocytes are also activated during the infective process. To improve the sensitivity of the neonatal infection screening test and to identify the types of leucocytes involved in the immune response to the infective organism, we studied further the up-regulation of a comprehensive range of surface activation markers on T cells, monocytes and natural killer (NK) cells from a group of 17 newborn patients with positive culture, a group of 40 possibly infected patients based on clinical signs and a control group. 'Normal' ranges were established for each activation marker for each leucocyte subset from 1 to 7 and 7-14-day-old newborns <35 weeks' gestation and 35-40 weeks' gestation. There was a significant increase in the percentage of T cells expressing CD25 in the peripheral blood from infants at 2 weeks of age. Expression of HLA-DR on T cells, CD25 and CD69 on monocytes and HLA-DR on NK cells was also increased significantly in the peripheral blood from infants at 2 weeks of age and may reflect a maturation of these functional surface molecules. Up-regulation of CD69 on NK cells was the most sensitive marker for neonatal sepsis (positive in 13/16 patients). CD69 and CD25 expression was increased significantly on T cells in 11/17 and 10/17 patients, respectively. A combination of CD45RA/CD45RO and CD45RO identified 11/16 infected patients. Measurement of CD69 expression on NK cells with CD45RA, CD45RO, CD25 and CD69 expression on T cells resulted in a significant increase in at least two leucocyte activation markers from infected patients. In conclusion, this is the first report of the up-regulation of CD69 on NK cells as a sensitive marker of neonatal infection. A combination of this marker with CD45RA, CD45RO, CD25 and CD69 expression on peripheral blood derived T cells is the most sensitive and specific for neonatal infection.

Physiological responses of the CAM epiphyte Tillandsia usneoides L. (Bromeliaceae) to variations in light and water supply

In an effort to understand the mechanisms that sustain rootless atmospheric plants, the modulation of Crassulacean acid metabolism (CAM) in response to variations in irradiance and water supply was investigated in the epiphyte Tillandsia usneoides. Plants were acclimated to three light regimes, i.e. high, intermediate and low, with integrated photon flux densities (PFD) of 14.40, 8.64 and 4.32 mol m-2 d-1 equivalent to an instantaneous PFD of 200, 100, and 50 mumol m-2 s-1, respectively. Daily watering was then withdrawn from half of the plants at each PFD for 7 d prior to sampling. In response to the three PFD treatments, chlorophyll content increased in plants acclimated to lower irradiances. Light response curves using non-invasive measurements of chlorophyll fluorescence demonstrated that photosystem II efficiency (phi PSII) was maintained in high PFD acclimated plants, as they exhibited a larger capacity for non-photochemical dissipation (NPQ) of excess light energy than low PFD acclimated plants. Net CO2 uptake increased in response to higher PFD, reflecting enhanced carboxylation capacity in terms of phosphoenolpyruvate carboxylase (PEPc) and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities. After water was withdrawn, nocturnal net CO2 uptake and accumulated levels of acidity declined in all PFD treatments, concomitant with increased respiratory recycling of malate. Examining the strategies employed by epiphytes such as T. usneodies to tolerate extreme light and water regimes has demonstrated the importance of physiological mechanisms that allow flexible carboxylation capacity and continued carbon cycling to maintain photosynthetic integrity.

Congenital bowel perforation in twin-to-twin transfusion syndrome

Two unrelated survivors of twin-to-twin transfusion syndrome (TTTS) presented with intestinal perforation at birth. Both were localised perforations without any suggestion of widespread ischaemic disease to the splanchnic bed. Histopathology from the perforation site showed evidence of focal ischaemic necrosis, presumably from a vascular accident. One infant later died of multiple organ failure with major brain damage, but the other survived without long-term sequelae. These two cases appear to represent an unreported variation of the ischaemic intestinal complications of TTTS.

Patterns of antropyloric motility in fed healthy preterm infants

BACKGROUND

Antropyloric motility is important for regulation of gastric emptying and has not been adequately characterised in premature infants.

AIM

To evaluate fed patterns of antropyloric motility in premature infants.

SUBJECTS

Forty three healthy premature infants, 30-38 weeks of postmenstrual age.

METHODS

Postprandial antropyloric motility was measured using a micromanometric feeding assembly (outer diameter 1.8 mm) incorporating a pyloric sleeve sensor. The occurrence of isolated pyloric pressure waves (IPPWs) and antral pressure wave sequences (PWSs) was characterised. Sequences were further classified as being antegrade, synchronous, antegrade-synchronous, and retrograde according to the direction of propagation.

RESULTS

A total of 7289 pressure wave events were recorded, 48% IPPWs and 52% PWSs (18% antegrade, 12% synchronous, 13% antegrade-synchronous, 2% retrograde, and 7% undefined). IPPWs predominated in the first postprandial hour, peaking at 30-60 minutes. PWSs predominated in the period after one hour postprandially. Mean (SEM) half gastric emptying time was 42 (4) minutes.

CONCLUSIONS

Monitoring of antropyloric motor patterns in healthy premature infants indicates that the neuroregulatory mechanisms responsible for the coordination of antropyloric motility and gastric emptying are well developed by 30 weeks of postmenstrual age.

Short-term plasticity of crassulacean acid metabolism expression in the epiphytic bromeliad Tillandsia usneoides

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. The regulation and flexibility of the crassulacean acid metabolism (CAM) pathway has been investigated in the 'extreme epiphyte' Tillandsia usneoides (L.). Submerging strands of T. usneoides under water, thereby inhibiting the supply of atmospheric CO2, allowed non-invasive in vivo manipulation of the supply of CO2 during the nocturnal Phase I of CAM. Once the plants were removed from submersion, T. usneoides maintained open stomata, and net CO2 uptake occurred throughout most of the photoperiod. Variability in the expression of CAM allowed T. usneoides to compensate for restricted CO2 availability through Phase I of CAM by adjusting gas exchange rates through the photoperiod and subsequent dark period to maintain a constant internal supply of CO2 in the light. Furthermore, T. usneoides demonstrated a gradual, rather than rapid, change in phosphoenolpyruvate carboxylase (PEPC) activation across the day-night cycle, such that PEPC and Rubisco appear to work in tandem in order to maintain carbon balance for this extreme atmospheric bromeliad.

A comparison of acupuncture with advice and exercises on the symptomatic treatment of osteoarthritis of the hip--a randomised controlled trial

Acupuncture is becoming a common technique within the physiotherapy profession as a treatment modality for pain relief; however, few randomised controlled trials have been undertaken to assess the effectiveness of acupuncture, particularly in the treatment of osteoarthritis (OA) of the hip. Therefore, a randomised trial to compare the effectiveness of acupuncture with advice and exercises on the symptomatic treatment of OA of the hip was carried out. Thirty-two patients awaiting a total hip arthroplasty were randomly allocated to either the experimental group, (A), to have six sessions of acupuncture each lasting up to 25 minutes, or the control group, (B), to be given advice and exercises for their hip over a six week period. Group A consisted of three men and 13 women, and group B consisted of four men and eight women. The average age in group A was 66 years and in group B it was 68 years. Patients were assessed for pain and functional ability, using a modified version of the WOMAC questionnaire, pre-treatment, immediately post-treatment and at eight weeks post-treatment. The pre-treatment WOMAC scores in the two groups were similar (p=0.85). There was a significant improvement in group A (decrease in WOMAC score) immediately post-treatment (p=0.002) and this was maintained at the eight-week follow-up (p=0.03). There were no significant changes in group B. When the changes in WOMAC scores were compared between groups, a significantly greater improvement was found between pre-treatment and immediately post-treatment in group A, compared with group B (p=0.02). The changes between pre-treatment and the eight-week follow-up also showed a significant improvement in group A compared with group B (p=0.03). In conclusion, this trial supports the hypothesis that acupuncture is more effective than advice and exercises in the symptomatic treatment of OA of the hip.

Eighteenth and nineteenth century dental restoration, treatment and consequences in a British nobleman

This paper examines unusual eighteenth and nineteenth century dental treatment and its consequences, in a nobleman excavated from beneath St. Nicholas' Church, Sevenoaks, Kent, UK in the early 1990s. This rare archaeological case exhibits erosion of dental enamel on the labial surface of all the anterior dentition. A programme of historical research suggests that this might be attributed to the application of an acid-based dental tincture or the use of an abrasive substance to whiten the teeth. Palliative treatment for the consequence of this application was prescribed by Dr Robert Blake of Dublin. Further, it bears witness to three dental restorations, two of gold and one tin. The two gold (foil) fillings are an occlusal in the upper-right second molar and a cervical on the labial surface of the upper left canine. The tin filling is an occlusal in the upper left second molar. Excavation of the carious tissue appears to have been undertaken using a spoon shaped implement.

Quality of life of mothers and families caring for preterm infants requiring home oxygen therapy: a brief report

OBJECTIVE

To investigate the impact on mothers and families of caring for a premature infant receiving home oxygen therapy (HOT).

METHODS

Standard questionnaires were used to compare the functioning of mothers and families of 10 premature infants receiving HOT, 10 premature infants who were discharged from hospital on HOT but who no longer required it and 20 premature infants who had never required treatment with HOT.

RESULTS

After adjustment for gestational age, chronological age, birthweight and place of residence (urban/rural), the care required by premature infants receiving HOT had a significantly greater impact on their families than the care of infants not receiving HOT. Mothers of premature infants receiving HOT reported significantly less vitality and more mental health problems than mothers of infants not receiving HOT.

CONCLUSIONS

The use of HOT for premature infants may have a significant adverse impact on their mothers and families.

Interactive television for an urban adult mental health service: the Guy's Psychiatric Intensive Care Unit Telepsychiatry Project

We carried out a feasibility study of an interactive television (IATV) system to enhance the provision of psychiatric intensive care services to a remote adult acute psychiatric ward in the same National Health Service mental health trust. The system used videoconferencing equipment connected by ISDN at 128 kbit/s. The system was used for patient referral, assessment and monitoring by staff at the remote site 8 km away.

Mechanism of gastroesophageal reflux in premature infants with chronic lung disease

BACKGROUND/PURPOSE

The aim of this study was to characterize the motor events responsible for gastroesophageal reflux (GER) and esophageal acid clearance in a cohort of preterm infants with chronic lung disease (CLD).

METHODS

Esophageal motility was recorded for 2 to 3 hours postprandially in 14 preterm infants with mild-moderate or moderate-severe CLD at 33 to 39 weeks postmenstrual age using a sleeve-side hole micromanometric assembly into which a pH probe had been installed.

RESULTS

Twenty-six acid GER episodes were recorded by pH probe. Of these, 22 (85%) were associated with transient lower esophageal sphincter (LES) relaxation. Transient LES relaxations were significantly longer in duration than single swallows (13.7 seconds v 4.6 seconds, P < .001) and had lower nadir pressures (1.1 mm Hg v 2.5 mm Hg, P < .001). During periods of esophageal acidification (pH below 4), peristaltic esophageal body pressure wave sequences cleared acid refluxate more effectively than nonperistaltic pressure wave sequences.

CONCLUSIONS

In preterm infants with CLD, transient LES relaxations are the predominant mechanism underlying GER, and esophageal clearance mechanisms are fully functional, which is similar to that seen in healthy preterm infants.

Measurement of upper esophageal sphincter tone and relaxation during swallowing in premature infants

Upper esophageal sphincter (UES) motor function has not been previously evaluated in premature infants. The motor patterns associated with tonic activity and swallow-related relaxation of the UES were recorded for 1 h after completion of gavage feeding in 11 healthy preterm neonates (postmenstrual age 33-37 wk) with a micromanometric assembly, which included a sleeve sensor specifically adapted for UES recordings. A clearly defined UES high-pressure zone was observed in all premature infants studied. Resting UES pressure ranged from 2.3 to 26.2 mmHg and was higher during periods of irritability and apparent discomfort. During dry swallows, UES pressure relaxed from a resting pressure of 28.2 +/- 4.0 mmHg to a nadir of 1.1 +/- 3.3 mmHg. The mean UES relaxation interval (the time from relaxation onset to relaxation offset) was 0. 31 +/- 0.11 s. We conclude that in premature infants >/=33 wk postmenstrual age the motor mechanisms regulating UES resting pressure and the onset of UES relaxation are well developed.

Reproducibility of the 13C-octanoic acid breath test for assessment of gastric emptying in healthy preterm infants

BACKGROUND

The 13C-octanoic acid breath test has been used to measure gastric emptying in preterm infants, but the reproducibility of the test has not been evaluated in this population.

METHODS

Fifty-six paired breath test analyses were performed on 28 healthy preterm infants 1 to 5 days apart using the same food type, volume, and energy content for each paired sample. Breath samples were taken before the feeding, at 5-minute intervals after feeding for 30 minutes, then each 15 minutes for 4 hours. Samples were analyzed using an isotope-ratio mass spectrometer, and 3C recovery was used to calculate values for gastric-emptying coefficient and gastric half-emptying time.

RESULTS

There was no significant difference between test results on different days in the paired samples studied. gastric-emptying coefficients for the first and subsequent samples were 2.6+/-0.1 (mean+/-SEM) and 2.7+/-0.1, respectively, and half-emptying times were 44.5+/-3.7 minutes and 41.4+/-3.2 minutes.

CONCLUSION

The 13C-octanoic acid breath test is a reliable, noninvasive, and reproducible measure of gastric emptying in preterm infants that should have wide application for use in this population.

Growth and neurodevelopmental outcome in extremely-low-birth-weight infants after laparotomy

Twenty-one extremely-low-birth-weight (ELBW) and premature infants (<29 weeks' gestation and/or <1,000 g) underwent emergency laparotomy for acute intra-abdominal pathology (necrotising enterocolitis [NEC] 16, other bowel pathology 5) during the 4-year period from 1990 to 1993; 11 died. The neurodevelopmental outcome of the 10 survivors was assessed and compared with 20 living, otherwise normal controls matched for gestational age, birth weight, and year of birth to asses the effect of the abdominal event on quality of survival. Those who survived after laparotomy had a worse neurodevelopmental outcome than controls (P < 0.05). During this period, we also compared 24 infants in the ELBW category who developed NEC but did not require a laparotomy with the 16 ELBW infants with NEC who required a laparotomy. Those who required a laparotomy had worse disease and had significantly worse neurodevelopmental outcomes (P < 0.01). ELBW and premature infants who have acute intra-abdominal pathology requiring a laparotomy are thus at increased risk of neurodevelopmental problems and poor growth. Close long-term follow-up is important, and the families of such infants should be made aware before surgery of the increased risk the abdominal event has on their babies' developmental outcome if they survive.

Mechanisms of gastroesophageal reflux in healthy premature infants

OBJECTIVES

The aim of this study was to characterize the motor events responsible for gastroesophageal reflux (GER) and esophageal acid clearance in a cohort of healthy preterm infants.

STUDY DESIGN

Esophageal motility was recorded for 2 to 3 hours after a feeding in 24 preterm infants, 31 to 38 weeks' postmenstrual age, by using a sleeveside hole micromanometric assembly incorporating a pH probe.

RESULTS

Sixty acid GER episodes were recorded by pH probe, and 133 non-acid GER episodes were recorded manometrically by the presence of esophageal common cavities. Of the 193 GER episodes, 159 (82%) were associated with transient lower esophageal sphincter relaxation (TLESR). TLESRs were significantly longer in duration than single swallows (15.1 seconds vs 5.6 seconds, P < .001) and had lower nadir pressures (0.8 mm Hg vs 2.3 mm Hg, P < .001). A total of 3216 esophageal body pressure waves were analyzed; 70% of swallow-induced pressure waves were peristaltic in sequence compared with 5% of swallow-unrelated pressure waves. During periods of esophageal acidification (pH below 4), peristaltic esophageal body pressure wave sequences cleared acid refluxate more effectively than nonperistaltic pressure wave sequences.

CONCLUSIONS

In healthy preterm infants, TLESRs are the predominant mechanism underlying GER, and esophageal clearance mechanisms are well developed by at least 31 weeks' postmenstrual age.