Necrotizing enterocolitis in term neonates: data from a multihospital health-care system

OBJECTIVE

In the past 5(1/2) years, 30 term or near-term neonates in the Intermountain Healthcare system developed necrotizing enterocolitis (NEC) Bell's stage > or =II. We sought to identify possible explanations for why these patients developed NEC, by comparing them with 5847 others that did not develop NEC, from the same hospitals and of the same gestational ages, cared for during the same 5 1/2-year period.

STUDY DESIGN

Data were collected from neonates admitted to any of the Intermountain Healthcare NICUs with a birth date from 1 January 2001 to 30 June 2006, and a gestational age >36 weeks. A variety of patient features and feeding practices were compared between those that did vs did not develop NEC.

RESULT

Forty-one neonates >36 weeks gestation were listed in the discharge records as having NEC of Bell's stage II or higher. However, on review of these 41 medical records, 11 were seen to have had NEC of Bell's stage I, whereas the remaining 30 had radiographs and clinical courses indicative of Bell's stage > or =II. Those 30 formed the basis of this study. Twenty-eight of the 30 developed NEC after having been admitted to an NICU for some other reason; the other two developed NEC at home, within 2 days of being discharged from an NICU. The 30 that developed NEC were more likely than the 5847 that did not develop NEC, to have congenital heart disease (P=0.000), polycythemia (P=0.002), early-onset bacterial sepsis (P=0.004) or hypotension (P=0.017). All 30 received enteral feedings before NEC developed; 29 were fed either artificial formula or a mixture of formula and breast milk. The one that was exclusively fed human milk was fed human milk with added fortifier (24 cal/oz). The 30 that developed NEC were more likely to be fed formula exclusively (P=0.000). Seven of the 30 had a laparotomy for NEC; two of the seven had total bowel necrosis and support was withdrawn. The other five had perforations and bowel resections. The mortality rate was 13% (4/30).

CONCLUSION

In our series, NEC among term or near-term neonates was exclusively a complication developing among patients already admitted to a NICU for some other reason. We speculate that the combination of reduced mesenteric perfusion and feeding with artificial formula were factors predisposing them to develop NEC.

Identifying patients, on the first day of life, at high-risk of developing parenteral nutrition-associated liver disease

BACKGROUND

Prolonged use of parenteral nutrition (PN) in neonates can lead to parenteral nutrition-associated liver disease (PNALD), manifested by elevated direct bilirubin concentrations, and in some cases progressing to hepatic failure. When new potential means of preventing PNALD in the neonatal intensive care unit (NICU), such as Omegaven usage, are tested in clinical trials, the studies should enroll neonates at a very high risk of developing PNALD. However, it is not always clear, in the first days of life, which neonates are most likely to develop PNALD. Therefore, preparatory to devising studies of prophylaxis against PNALD, we conducted an evaluation of all NICU patients who received PN for >or=14 day, assessing their likelihood of developing PNALD.

METHODS

We performed an historic cohort analysis of all neonates in the Intermountain Healthcare system, receiving PN for 14 days or more during their stay, with dates of birth between 1 January, 2002 and 30 June, 2006.

RESULTS

During the 4(1/2)-year period, 9861 neonates were cared for in the Intermountain Healthcare NICUs. Of these, 9547 (96.8%) survived for at least 28 days, and of these 6543 (68.5%) received PN. Twenty-one percent (1366 patients) of those receiving PN, received it for >or=14 days. PNALD was ascertained in this group by a direct bilirubin >or=2.0 mg/dl. Neonates receiving PN for 14-28 days had a 14% incidence of PNALD, those receiving PN for 29-56 days had a 43% incidence, those receiving PN for 57-100 days had a 72% incidence and those receiving PN for >100 days had a 85% incidence. Groups of patients identifiable on the first day of life as having the highest risk of developing PNALD were birth weight <500 g (odds ratio (OR), 30.7), birth weight 500-749 g (OR, 13.1), gastrochisis (OR, 20.3) and jejunal atresia (OR, 24.0). Among 357 patients who developed PNALD, the highest direct bilirubin concentrations correlated with the highest serum alkaline phosphatase and transaminase concentrations. Deaths after 28 days were much more common in those with the highest direct bilirubin and transaminase concentrations (P<0.0001).

CONCLUSIONS

In the first days of life, certain NICU patients can be identified as being at very high risk for developing PNALD. These are patients <750 g birth weight, those with gastrochisis and those with jejunal atresia. We speculate that these groups would be reasonable subjects for including in a PNALD prophylaxis trial, testing new preventative strategies such as Omegaven usage.

Congenital Corneal Anesthesia

Congenital corneal anesthesia is a rare clinical entity that poses a diagnostic dilemma, particularly in the pediatric age group. The sensory deficit may be confined to the cornea, or extend to other divisions of the trigeminal nerve. The sensory deficit may occur as an isolated abnormality, as part of a complex neurological syndrome, or it may occur in association with multiple somatic abnormalities and congenital insensitivity to pain. This condition usually presents between the ages of 8 to 12 months. Poor vision, photophobia, conjunctival injection, and corneal ulceration in the absence of pain and distress in a child should alert the clinician to the possibility of anesthetic cornea. In the early stages of presentation, punctuate keratopathy is the main feature, which may progress to non-healing persistent corneal epithelial defects. This stage may progress to acute corneal lysis and perforation. In most patients, conservative approaches such as copious lubrication, prevention of self-harm and cautious use of bandage contact lenses are effective in preventing progressive corneal damage. Tarsorrhapy is effective in promoting epithelial healing and permanent lateral tarsorraphy may prevent further development of epithelial defects. Amniotic membrane graft may be considered in order to improve epithelial healing. Corneal grafts carry a poor prognosis. Accurate initial diagnosis, evaluation, and proper management are paramount to prevent visual loss due to long-term complications of corneal anesthesia. This review of the literature outlines the problems and approaches in diagnosis, evaluation, and management of this rare condition.

Modelling and dynamic simulation of a pilot-scale moving bed bioreactor for the treatment of municipal wastewater: model concepts and the use of respirometry for the estimation of kinetic parameters

A model for the simulation of a moving bed bioreactor (MBBR) used for the treatment of municipal wastewater is proposed. The model includes attachment of particulates to the biofilm and detachment of biofilm into the bulk liquid. The growth kinetics are modelled with the activated sludge model no. 1 (ASM1). Respirometry was used for the estimation of kinetic parameters. The resulting respirograms featured the typical endogenous and exogenous respiration phases and the respirogram shapes were as expected from analogous respirometry with activated sludge. The estimated parameter set was used for modelling and simulation of the pilot-scale MBBR. The main proportion of biomass in the MBBR was found to be attached as biofilm on the carrier elements (4.1 -4.6 g dm-3) and only a small amount was suspended in the bulk liquid (0.15gdm(-3)). Attachment and detachment rates were estimated to be 4.8-7.5g m(-2) d(-1) 1for attachment and 6.5-7.5g m(-2) d(-1) for detachment. The biofilm age was estimated to be 1.8-2.7d. The model was used to predict effluent quality parameters and a good fit of the simulated data to the measured data originating from a four-days-long measurement campaign was obtained.

Hematological abnormalities during the first week of life among neonates with Down syndrome: Data from a multihospital healthcare system

Various hematological abnormalities have been reported among neonates with Down syndrome. Thrombocytosis, thrombocytopenia, polycythemia, neutrophilia, transient myeloproliferative disorder (TMD), and congenital leukemia have all been reported. The two largest case series previously reported involved 63 and 31 cases. To acquire hematological data from a larger case series, we obtained all CBCs done during the first week after birth on all neonates with Down syndrome cared for in an Intermountain Healthcare (IHC) hospital with a date of birth between January 1, 2001 and December 31, 2005. During this period, 145,522 live births were recorded at 18 hospitals. Down syndrome was recognized in 226 (1 in 644). One hundred fifty-eight (70%) of these had one or more CBCs obtained before the seventh day (144 hr). Neonates who did versus did not have a CBC in the first week had a similar gestational age, birth weight, percentage who were LGA and SGA, and length of stay. Neutrophilia was the most common hematological abnormality detected, with 80% of absolute neutrophil counts above the upper limit of normal for age. Six percent (9/158) had blasts identified on the blood film and three, where this was persistent, were referred to the pediatric hematology service for further evaluation. The next most commonly detected abnormality was thrombocytopenia, with 66% of platelet counts <150,000/microl, and with 6% of counts <50,000/microl. The mean platelet volume did not correlate with the platelet count, but tended to run slightly large (9.2 +/- 1.3 fl), with 24% of values above 10 fl. Only one had a platelet transfusion. Polycythemia was the next most common hematological abnormality detected, with 33% of hematocrit values above 65% or hemoglobin concentrations above 22 g/dl. Six had a reduction transfusion. One patient had significant anemia (hematocrit <15%) and received an erythrocyte transfusion. One had neutropenia associated with an infection after bowel surgery. Neutrophilia, thrombocytopenia, and polycythemia were the most common hematological abnormalities observed among neonates with Down syndrome. Anemia, thrombocytosis, and neutropenia were not more common than among neonates who do not have Down syndrome. Hematological abnormalities were so common in this group that it seems reasonable to recommend that one or more CBCs be obtained on all neonates with Down syndrome.

Low blood neutrophil concentrations among extremely low birth weight neonates: data from a multihospital health-care system

OBJECTIVE

A blood neutrophil concentration < 1000/microl has been reported to occur in about 8% of neonatal intensive care unit (NICU) patients, at some time during their hospital stay. However, the incidence of this finding among extremely low birth weight (ELBW) neonates (< 1000 g birth weight) is not known. Using data from four NICU's in one health-care system, we sought to estimate the incidence, timing, causes, severity and duration of neutrophil counts < 1000/microl among ELBW neonates. We also tabulated the treatments used for this condition and associations with mortality.

METHODS

We performed an historic cohort analysis of all ELBW neonates born during the 36-month period, 1 July 2002 to 30 June 2005, cared for in the four Intermountain Healthcare level III NICU's.

RESULTS

Three hundred and thirty-eight ELBW neonates were the subjects of the analysis. Complete blood cell counts (CBCs) were obtained in all (range, 1 to 123 CBCs/patient). Thirty-eight percent (128/338) had one or more neutrophil counts < 1000/microl. In 57% the low neutrophil count persisted for < 24 h; in 43% it persisted for 1 to 7.5 days. Most of the cases (74%) were detected during the first 3 days of life. Twenty-two percent of cases were not detected until after the first week. Low neutrophil counts were more common among the smallest patients, with a 63% incidence in those < or = 500 g, 44% in those 501 to 600 g and 34% in those 801 to 999 g. When low neutrophil counts were recognized during the first 3 days of life, the patients were typically either small for gestational age (SGA; weight < 10th percentile for gestational age) or born after pregnancy-induced hypertension (PIH) (68%), or had early-onset bacterial infection (6%). When recognized after the first 3 days, the patients typically had necrotizing enterocolitis (31%) or a nosocomial bacterial infection (19%). Alloimmune mechanisms were not tested for in any of the cases. No cause for the low counts was identified among 35% of the neutropenic patients. Intravenous immunoglobulins was administered to 28% of cases, and 100% of these were given according to our written guidelines. Recombinant granulocyte-colony stimulating factor was administered to 13% of cases, and 69% of these were given according to guidelines. Neither the presence of low neutrophil counts nor the severity (lowest recorded count) correlated with mortality rate, except in proven early-onset sepsis.

CONCLUSIONS

We observed low neutrophil counts among ELBW neonates at a rate five times that reported in the general NICU population. Most cases were present in the first days of life and occurred in SGA neonates or those with PIH. In over 1/3, no cause was discovered. We maintain that more consistency is needed in evaluating and treating neutropenia among ELBW neonates.

Thrombocytopenia among extremely low birth weight neonates: data from a multihospital healthcare system

OBJECTIVES

Thrombocytopenia is common in neonatal intensive care units (NICU), with 18 to 35% of patients developing this problem before hospital discharge. It might be even more common among extremely low birth weight neonates (ELBW, < or = 1000 g birth weight). However, little is known about thrombocytopenia in the ELBW population. We sought to determine the incidence, timing, causes, platelet transfusions given, and outcomes of thrombocytopenia among ELBW neonates.

STUDY DESIGN

We performed a cohort analysis of all 284 ELBW neonates born during 2003 and 2004 cared for in any of the Intermountain Healthcare level III NICUs.

RESULTS

Multiple platelet counts were obtained in all 284 (range, 4 to 441 platelet counts/patient). Of the 284, 208 (73%) had one or more platelet counts < or =150 000/microl. Most were detected during the first days of life; 80% were detected during the first week and only 20% were detected thereafter. Thrombcytopenia was more common among the smallest patients; 85% incidence among those < or =800 g, 60% among those 801 to 900 g, and 53% among those 901 to 1000 g. Platelet transfusions were given to 129 of the 208 thrombocytopenic neonates. More than 90% were given prophylactically (the patient was not bleeding). The mortality rate among those that received platelet transfusions was twice that of those that received no platelet transfusions (P < 0.01). In 48% of cases, the cause of the thrombocytopenia went undiagnosed. The most common explanations were being small for gestational age or delivered to a hypertensive mother, DIC, bacterial infection, fungal infection, and necrotizing enterocolitis, respectively.

CONCLUSIONS

We observed thrombocytopenia among ELBW neonates at a rate more than twice that reported among the general NICU population. Much remains to be discovered about the etiology and best treatments of thrombocytopenia among ELBW neonates.

Clinicians taking pictures--a survey of current practice in emergency departments and proposed recommendations of best practice

The primary objective of this survey was to establish current practice in emergency departments in the UK. Variation in obtaining consent, how image collection is achieved, and the images stored were considered to be important outcomes. An initial postal questionnaire followed by phone survey posed questions about practical and procedural issues when capturing clinical images in emergency departments in the UK. Altogether, 117 departments replied out of 150 surveyed. Only 21 departments have a written policy permitting medico-legal case photography. A total of 53 do take clinical photographs where no policy exists, seven of which actively take assault/domestic violence images, only four of which document consent. All departments with photographic facilities take images for clinical/teaching purposes. Thirty two of those without a policy attach the photograph to the clinical notes and so may be potentially called upon for medico-legal proceedings if relevant, which raises issues of adequate consent procedures, storage, and confidentiality. This is particularly pertinent with the increasing use of digital photography and image manipulation. A large variation in current practice has been identified in relation to a number of issues surrounding clinical image handling in emergency departments. Subsequently, recommendations for best practice have been proposed to protect both the patient and the clinician with regards to all forms of photography in the emergency department setting.

First Report of Leifsonia xyli subsp. xyli, Causal Agent of Ratoon Stunting of Sugarcane, in Jamaica

To our knowledge, this is the first report that Leifsonia xyli subsp. xyli, previously named Clavibacter xyli subsp. xyli (2), has been detected and identified in sugarcane in Jamaica. Although ratoon stunting (also known as ratoon stunting disease or RSD) has been reported in Jamaica since 1961, presence of the pathogen had never been confirmed in symptomatic tissues. A major industry-wide survey conducted in 1987 using the fluorescent antibody staining technique failed to detect positives in any of the 61 fields sampled in Jamaica. A new survey was conducted in 2004 on eight estates and the Sugar Industry Research Institute (SIRI) in Jamaica. Six arbitrarily selected stalks were sampled from each of 64 fields representing 25 different sugarcane cultivars. A 1-cm diameter core was extracted from the center of the bottom part of the stalk and used to detect the pathogen by tissue blot immunoassay (TBIA) (3). L. xyli subsp. xyli was detected in 26 of 384 samples (7%). At least one positive sample was found in 10 fields and seven cultivars and in one case (sugarcane cv. D14146 at the St Thomas Sugar Estate), all six stalks sampled in a field were positive. The highest number of infected fields (6 of 10) occurred at Worthy Park where cane yield in 2004 was 86.54 tons per ha compared with an average of 68.04 tons per ha for major estates in Jamaica (1). This latter result would indicate that where good quality agronomic practices are maintained, the effect of ratoon stunting might not be substantial or that sugarcane cultivars grown at this location were resistant to ratoon stunting. Pathogen identification was confirmed using nested polymerase chain reaction (PCR) with three samples from a TBIA-positive field of cv. D14146. Primary primers were RSD 33 (CTGGCACCCTGTGTTGTTTTC) and RSD 297 (TTCGGTTCTCATCTCAGCGTC) and secondary, nested primers were RST60 (TCAACGCAGAGATTGTCCAG) and RST59 (CGTCTTGAAGACACAGCGATGAG). The thermocycler parameters were denaturization at 94°C for 4 min, 31 cycles at 94°C for 30 s, 55°C for 30 s, 65°C for 1 min, and final extension at 65°C for 3 min. The nested-PCR product (approximately 230 bp) of each sample was cloned and sequenced. It showed 99 to 100% identity with the 16S-23S intergenic spacer region of L. xyli subsp. xyli, thus confirming occurrence of ratoon stunting in Jamaica. Since this study, the SIRI has installed a hot-water treatment plant and will heat-treat cuttings before planting the nurseries with new sugarcane clones selected for release to growers. The SIRI will also conduct screening for ratoon stunting resistance to ensure that susceptible clones are not released to the industry. Meanwhile, the SIRI will do a more intense survey so that a more comprehensive picture may be obtained of the presence of ratoon stunting in Jamaica. References: (1) Anonymous. Annual Report of the Sugar Industry Research Institute, Jamaica, 2004. (2) L. I. Evtushenko et al. Int. J. Syst. Evol. Microbiol. 50:371, 2000. (3) N. A. Harrison and M. J. Davis. Phytopathology 78:722, 1988.

Pattern of daily weights among low birth weight neonates in the neonatal intensive care unit: data from a multihospital health-care system

OBJECTIVES

We sought to generate a contemporary postnatal weight grid for low birth weight (LBW, <2500 g) neonates using actual data, not mathematically derived idealized weight curves. To do this, we collected electronic data from all neonatal intensive care units (NICU) patients weighing 400-2600 g at birth, during 30 consecutive months (January 2003-June 2005) in all four NICU's within a single health system, Intermountain Health Care (IHC).

METHODS

A deidentified limited data set was collected from electronic IHC records. Data were limited to the birth weights and all subsequent daily weights, until discharge, death, or transfer to a non-IHC facility. Lines were drawn connecting the exact daily means of body weight for patients in 200 g birth weight groupings, ranging from 400 to 2600 g. We assessed differences in growth patterns predicted by this grid vs three previously published NICU longitudinal weight grids.

RESULTS

All recorded weights were electronically extracted for 1813 consecutive patients with dates of birth from January 1, 2003 through June 30, 2005. The daily weights of each patient totaled over 48,000 individual data points. The new grid differed from previously published grids, in that the new grid showed; (1) no predicted postnatal weight loss among neonates in categories<900 g birth weight, (2) less initial weight loss among neonates 900-2500 g, (3) fewer days to regain birth weight among neonates<or=2000 g, and (4) fewer days to gain 100 and 300 g above birth weight in neonates<or=1500 g.

SPECULATION

For charting serial weights of LBW neonates in the NICU the new grid may be a useful standard.

Enhanced endothelium derived hyperpolarising factor activity in resistance arteries from normal pressure glaucoma patients: implications for vascular function in the eye

BACKGROUND/AIMS

Endothelial cell dysfunction in the ocular circulation may contribute to normal pressure glaucoma (NPG). This study aimed to investigate the contributions made by endothelium derived relaxing factors to relaxation of (1) subcutaneous resistance arteries from patients with NPG, and (2) porcine ciliary arteries.

METHODS

Human gluteal resistance arteries were isolated from seven patients with NPG and matched controls. Human and porcine arteries produced endothelium dependent relaxation when exposed to acetylcholine (ACh) (10(-9)-3 x 10(-5)M) or bradykinin (10(-10)-3 x 10(-6)M). Pharmacological agents were used to inhibit the nitric oxide pathway (l-arginine analogues, soluble guanylate cyclase inhibitor), endothelium derived hyperpolarising factor (EDHF) activity (potassium channel antagonists), and prostaglandin synthesis (cyclo-oxygenase inhibitors).

RESULTS

In all arteries, endothelium dependent relaxation was attenuated by nitric oxide (NO) inhibition or potassium channel blockade, but not by cyclo-oxygenase inhibition. Inhibition of ACh mediated relaxation by potassium channel antagonists was greater (p<0.05) in patients with NPG (Emax, 55.4% (SD 8.16%) relaxation, n = 4) than controls (Emax, 81.8% (6.0%), n = 5). In contrast, combined inhibition of NO synthase (NOS) and cyclo-oxygenase produced similar inhibition of ACh mediated relaxation in both groups.

CONCLUSIONS

The enhanced contribution of EDHF to ACh mediated relaxation in systemic resistance arteries from NPG patients may contribute to the maintained endothelium mediated relaxation in these vessels. EDHF also contributes significantly to bradykinin mediated relaxation in porcine ocular ciliary arteries. Therefore, similar changes in the balance of relaxing factors in the ocular circulation could influence the response of the eye to vascular endothelial dysfunction in NPG.

Advanced esophageal cancer

Although the prognosis for patients with early cancer is good, throughout the world the majority of patients present with advanced disease, and in them, survival is poor. Accurate staging is essential to inform prognosis; to select candidates who may be cured by surgery alone; to select patients requiring neoadjuvant therapy, especially when new protocols are being studied; and to detect patients with advanced disease who would be best served by palliative therapy.

Endoscopic ultrasonography (EUS) in the staging of malignancy

Since first introduced over 20 years ago, endoscopic ultrasonography (EUS) has become established as an important tool in the staging of gastrointestinal malignancies and potentially resectable non-small cell lung cancer. This review describes the current roles of EUS in staging these tumours, highlighting interventional roles, current problem areas and future developments.

Generation of a double shock driven by laser

The feasibility and reliability of a multiple laser shock generation to study the equation of state surface off the principal Hugoniot curve and to approach an isentropic compression has been demonstrated. The technique is based on the use of a double laser pulse. A strong shock was generated in iron targets precompressed by a first weak shock. The effect of precompression was studied. The experiment was performed at the Laboratoire pour l'Utilisation des Lasers Intenses laboratory.

Observation of laser driven supercritical radiative shock precursors

We present a supercritical radiative shock experiment performed with the LULI nanosecond laser facility. Using targets filled with xenon gas at low pressure, the propagation of a strong shock with a radiative precursor is evidenced. The main measured shock quantities (electronic density and propagation velocity) are shown to be in good agreement with theory and numerical simulations.

Studies of acid exposure immediately above the gastro-oesophageal squamocolumnar junction: evidence of short segment reflux

BACKGROUND AND AIMS

Oesophageal pH is conventionally recorded from a point 5 cm above the lower oesophageal sphincter. However, the mucosal changes of reflux oesophagitis and intestinal metaplasia tend to affect the segment of oesophagus distal to this and close to the squamocolumnar junction. This study set out to investigate oesophageal acid exposure of squamous mucosa close to the squamocolumnar junction.

METHODS

Dual channel 24 hour pH monitoring was carried out in 11 patients with endoscopy negative dyspepsia and no evidence of gastro-oesophageal reflux by conventional oesophageal pH metry. Oesophageal pH was recorded from electrodes positioned 5 mm and 55 mm proximal to the squamocolumnar junction. A novel technique was developed using metal clips to secure the pH catheter to the oesophageal mucosa and maintain these electrode positions. Oesophageal manometry indicated that the distal electrode was within the high pressure zone of the lower oesophageal sphincter.

RESULTS

We found that 24 hour oesophageal acid exposure (per cent time pH <4) was greater 5 mm above the squamocolumnar junction compared with the conventional position 5 cm more proximal (11.7% v 1.8%; p<0.001). The greater acid exposure at the distal versus the conventional site was apparent in both the upright (12.7% v 2.3%) and supine (10.5% v 1.3%) positions, as well as during preprandial (14.2% v 1.6%) and postprandial (21.8% v 2.8%) periods (p<0.001 for each). The number of reflux events recorded close to the squamocolumnar junction was also higher than at the conventional position (168 v 33; p<0.001). There was no correlation between acid exposure at the two sites.

CONCLUSIONS

The squamous mucosa of the most distal oesophagus is exposed to substantial acidic reflux, even in patients without evidence of conventional reflux disease. This short segment reflux may explain the high incidence of metaplasia and neoplasia at the gastro-oesophageal junction.

[Cherubism: the value of imaging and preoperative embolization]

Cherubism is a benign, hereditary, autosomal dominant disease, with variable penetrance and expressivity. It presents as a characteristic indolent deformity of the lower half of the face, associated with multicystic bone tumors. The definitive diagnosis is established by pathology. Radiology contributes greatly to its diagnosis (CT or MRI scan), and preoperative arterial embolization can provide valuable help to the surgeon when excision of this hemorrhagic lesion is necessary. The present article presents a case showing the advantage of this type of devascularization prior to surgery, not previously described in the literature.

Dietary nitrate generates potentially mutagenic concentrations of nitric oxide at the gastroesophageal junction

BACKGROUND & AIMS

Twenty-five percent of absorbed dietary nitrate is re-secreted in saliva, and 30% of this is reduced to nitrite by buccal bacteria. When saliva is swallowed, the acidic gastric juice reduces the nitrite to nitric oxide. The aim of this study was to examine the anatomic distribution of nitric oxide generation within the lumen of the upper gastrointestinal tract under basal conditions and after ingesting nitrate equivalent to that in salad portion.

METHODS

Using custom-made sensors, the dissolved luminal nitric oxide concentration and pH were measured at 1-cm increments for 2 minutes throughout the length of the stomach and distal esophagus in 15 Helicobacter pylori-negative healthy volunteers with and without ingestion of 2 mmol potassium nitrate. Serum nitrate and saliva nitrite concentrations were also monitored.

RESULTS

The nitrate ingestion increased mean (range) serum nitrate from 30 micromol/L (18-49) to 95 micromol/L (32-152), mean salivary nitrite from 36 micromol/L (19-153) to 252 micromol/L (32-600), and mean peak luminal nitric oxide concentration from 4.7 micromol/L (1.4-7.8) to 23.2 micromol/L (2.1-50) (P < 0.05 for each). After nitrate, the peak nitric oxide concentration occurred in 11 of the 15 (73%) subjects within 1 cm distal to the gastroesophageal pH step-up point. The mean nitric oxide concentration over the 1-cm segment immediately distal to the gastroesophageal pH step-up after nitrate was 7.5 micromol/L (range, 0.5-30.7) and was significantly higher than at all other sites. Nitric oxide concentrations greater than 50 micromol/L were observed at the precise location where neutral esophageal pH fell to acidic gastric pH.

CONCLUSIONS

Luminal generation of nitric oxide from dietary nitrate via salivary nitrite is maximal at the gastroesophageal junction and cardia. The high concentrations of nitric oxide generated may contribute to the high incidence of mutagenesis and neoplasia at this site.

Randomised trial of endoscopy with testing for Helicobacter pylori compared with non-invasive H pylori testing alone in the management of dyspepsia

OBJECTIVE

To compare the efficacy of non-invasive testing for Helicobacter pylori with that of endoscopy (plus H pylori testing) in the management of patients referred for endoscopic investigation of upper gastrointestinal symptoms.

DESIGN

Randomised controlled trial with follow up at 12 months.

SETTING

Hospital gastroenterology unit.

PARTICIPANTS

708 patients aged under 55 referred for endoscopic investigation of dyspepsia, randomised to non-invasive breath test for H pylori or endoscopy plus H pylori testing.

MAIN OUTCOME MEASURE

Glasgow dyspepsia severity score at one year. Use of medical resources, patient oriented outcomes, and safety were also assessed.

RESULTS

In 586 patients followed up at 12 months the mean change in dyspepsia score was 4.8 in the non-invasive H pylori test group and 4.6 in the endoscopy group (95% confidence interval for difference -0.7 to 0.5, P=0.69). Only 8.2% of patients followed up who were randomised to breath test alone were referred for subsequent endoscopy. The use of non-endoscopic resources was similar in the two groups. Reassurance value, concern about missed pathology, overall patient satisfaction, and quality of life were similar in the two groups. The patients found the non-invasive breath test procedure less uncomfortable and distressing than endoscopy with or without sedation. No potentially serious pathology requiring treatment other than eradication of H pylori was missed.

CONCLUSION

In this patient group, non-invasive testing for H pylori is as effective and safe as endoscopy and less uncomfortable and distressing for the patient. Non-invasive H pylori testing should be the preferred mode of investigation.