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Biomedical subjects

A Pierro

Publications and source records attributed to A Pierro.

At least 37 records · Page 2Linked to original sources

Gut overgrowth with abnormal flora: the missing link in parenteral nutrition-related sepsis in surgical neonates.

BACKGROUND AND AIMS: Patients receiving parenteral nutrition are at risk of septicaemia. Intestinal dysmotility and impaired gut immunity due to parenteral nutrition promote bacterial overgrowth. Gut overgrowth with aerobic Gram-negative bacilli (AGNB) impairs systemic immunity. The aim of this study was to determine the potential role of gut overgrowth with AGNB in the pathogenesis of septicaemia related to parenteral nutrition. METHODS: A prospective 5 y study of surgical infants less than 6 months of age was undertaken. Surveillance samples of the oropharynx and gut were obtained at the start of parenteral nutrition and thereafter twice weekly, to detect AGNB carriage. Blood cultures were taken on clinical indication only. RESULTS: Two-hundred and eight infants received parenteral nutrition for 6271 days (median 13 days, range 1-512 days). The incidence of AGNB carriage was 42%, whilst the septicaemia rate was 15%. Eighty-four percent of septicaemic infants carried AGNB, whilst 16% never carried AGNB (P<0.005). Carriage developed significantly earlier than septicaemia. CONCLUSIONS: The incidence of septicaemia was significantly greater in the subset of abnormal carriers. Although gut overgrowth with abnormal flora reflects illness severity, the fact that it preceded septicaemia implicates AGNB overgrowth, per se, as a contributory factor in the development of septicaemia related to parenteral nutrition. Prevention is unlikely to be successful if it ignores the abnormal flora.

Bacteremia↗

Myocardial carnitine palmitoyltransferase I as a target for oxidative modification in inflammation and sepsis.

CPT I (outer membrane carnitine palmitoyltransferase I) is a crucial enzyme in myocardial substrate selection. Two isoforms exist in the heart, the liver (L-) and muscle (M-) isoforms, which have different kinetic characteristics and alter in relative amounts during the neonatal/weaning/adult transition. CPT I is a point for control and regulation of fatty acid oxidation via modulation of its activity by malonyl-CoA, the concentration of which is set by acetyl-CoA carboxylase, AMP-activated protein kinase and malonyl-CoA decarboxylase in response to, for example, alterations in glucose supply. Systemic inflammatory responses and sepsis lead to myocardial dysfunction as part of multiple system organ failure. We have shown that: (i) myocardial CPT I activity is inhibited during neonatal sepsis; (ii) on the basis of inhibitor studies this inhibition appears to be of M-CPT I rather than L-CPT I; (iii) nitration of M-CPT I occurs, probably by peroxynitrite, and this may be responsible for the decrease in CPT I activity; (iv) myocardial CPT I activity is also inhibited in another model of systemic inflammatory response, namely intestinal ischaemia/reperfusion injury, but this can prevented by whole-body moderate hypothermia. Inhibition of M-CPT I would be predicted to alter myocardial substrate selection but there are several questions that remain to be answered.

Animals↗

Surgical infants on total parenteral nutrition have impaired cytokine responses to microbial challenge.

BACKGROUND/PURPOSE: Cytokines are essential for the prevention of microbial infections. Total parenteral nutrition (TPN) in infancy is associated with an increased risk of infection, and this could be related to altered cytokine production. The aim of the study was to determine if cytokine production is altered in monocytes from surgical infants receiving TPN. METHODS: There were 3 study groups: (a) infants receiving TPN, (b) enterally fed healthy control infants, and (c) enterally fed healthy control adults. Blood samples were incubated with either Escherichia coli LPS, Staphylococcus epidermidis, or with medium alone. Flow cytometry was used to measure monocyte intracellular cytokine: tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-1beta. RESULTS: After LPS stimulation, the percent of monocytes producing TNF-alpha and IL-6 were lower in infants on TPN than both control infants and adults. This was most apparent for TNF-alpha. The difference for IL-1beta was significant only between infant on TPN and control adults. When blood was stimulated with S. epidermidis, all 3 cytokines were significantly lower in the TPN group compared with control adults. However, the differences between infants on TPN and infant controls only reached statistical significance for IL-6. CONCLUSIONS: The inflammatory response to bacterial challenge is impaired in infants on TPN compared with enterally fed infants or adults. The pattern of this response may be dependent on the nature of the microbial challenge. Our results indicate that the susceptibility of TPN-fed surgical infants to bacterial infections may in part be caused by impaired cytokine responses after bacterial invasion.

Adult↗

Conservative management of pneumatosis intestinalis and pneumoperitoneum following bone-marrow transplantation.

Pneumatosis intestinalis (PI), with or without pneumoperitoneum (PP), may complicate allogenic bone-marrow transplantation (BMT). The aim of our study was to establish the incidence and outcome of this complication following BMT in children. A departmental database was used to identify children who underwent BMT in the 4-year period up to December 1999. The medical records of children who developed PI with or without PP were obtained for further study. All patients were managed without recourse to surgery. Conservative management included 7 days of intravenous antibiotics and 10 days of intestinal rest supported by parenteral nutrition. In the study period, 138 BMTs were carried out. Six children (4%) with a total of 7 episodes of PI/PP were identified, 1 boy and 5 girls with a median age of 8.5 years (range 0.8-11). Neutropenia was noted in 3 children at the time of presentation. Other risk factors identified included alternative BMT donors (5/6), steroid therapy (6/7), and graft-versus-host disease (5/6). Organisms were isolated from stool cultures sent at the time of diagnosis in 3 out of 7 instances. Diarrhoea was the predominant presenting symptom. All patients recovered from the acute episode, but 5 died at a mean of 12 months from the development of PI/PP (range 6-17 months). This mortality of 83% compares with a mortality of 33% (43 of 132) for the remainder of children who underwent BMT during the study period. Thus, while initial recovery can be anticipated, the medium-term mortality in this group of children is high.

Anti-Bacterial Agents↗

Infection rates in surgical neonates and infants receiving parenteral nutrition: a five-year prospective study.

We performed a prospective, observational, cohort study on 208 surgical neonates and infants between 1992 and 1997. Surveillance cultures of the oropharynx and rectum were obtained at the start of parenteral nutrition and thereafter twice weekly. Blood cultures were taken on clinical indication only. Microbial translocation was diagnosed when the micro-organisms in the blood were not distinguishable from those carried in the oropharynx and/or rectum. Liver function was monitored weekly and when septicaemia was suspected. The incidence of septicaemia was 15%. The predominant micro-organisms (86%) were the low-level pathogens, coagulase-negative staphylococci and enterococci. Potential pathogens, including aerobic Gram-negative bacilli, were responsible for the remainder. Microbial translocation was responsible for 84% of septicaemic episodes in 76% of patients. The potential pathogens caused septicaemia significantly later than coagulase-negative staphylococci, at a time when liver function was significantly more impaired. In neonates and infants receiving parenteral nutrition, septicaemia is mainly a gut-derived phenomenon and requires novel strategies for prevention.

Bacteremia↗

T cryptantigen activation is associated with advanced necrotizing enterocolitis.

BACKGROUND/PURPOSE: Thomsen-Friedenreich cryptantigen activation (TCA) exposes neonates with necrotizing enterocolitis NEC to the risk of hemolysis after transfusion of blood products. The authors aimed to determine the prevalence of TCA in neonates with NEC and to correlate TCA with severity of disease and outcome. METHODS: One hundred four neonates with NEC were tested for TCA on admission. Patients with TCA requiring transfusion were given packed red cells, low-titer anti-T fresh frozen plasma, and washed platelets to avoid hemolysis. RESULTS: Twenty-three infants had TCA, and 96% of these had stage III disease. The incidence of TCA was significantly higher in infants with stage III disease compared with those with stage II (30% v 4%; P <.01). A total of 91% of infants with TCA required laparotomy compared with 81% of those with no activation. At laparotomy, widespread disease was more common in the TCA group (71% v 55%). TCA did not significantly increase mortality rate (TCA, 39% v no TCA, 28%); this may reflect the transfusion policy of our unit. CONCLUSIONS: Twenty-two percent of neonates with NEC referred to our unit had TCA. There is an association between TCA and advanced NEC. Screening of neonates with advanced NEC for TCA is advised to identify those at risk of hematologic complications.

Antigens, Tumor-Associated, Carbohydrate↗

Hirschsprung's disease: functional and psychological follow up comparing total colonic and rectosigmoid aganglionosis.

AIMS: To compare the long term functional and psychosocial outcomes following surgical treatment for total colonic aganglionosis (TCA) with those in an age and gender matched group of patients with rectosigmoid aganglionosis (RSA). METHODS: Fifteen patients with TCA matched for age and gender with 15 patients with RSA were studied 7-17 years after the definitive operation. The internal and external sphincters were examined using anal endosonography. Functional outcome (faecal continence) was assessed by a surgeon not involved in the patients' care, and by a research psychologist in separate assessment sessions. The behavioural and emotional status of the patients was also assessed. RESULTS: Based on the surgeon's assessment, 6/15 TCA and 7/15 RSA patients were continent. In comparison, based on the psychological interview, 2/15 TCA and 6/15 RSA patients were continent. The TCA patients reported significantly more behavioural/emotional problems and lower levels of self esteem than the RSA patients. The parent and teacher assessments of psychosocial status revealed no differences between the groups. There was no association between incontinence and psychosocial adjustment in either group. There was no association between the assessments of functional outcome and the endosonographic appearance of the anal sphincters. CONCLUSIONS: The proportion of patients with faecal incontinence 7-17 years after definitive surgery was high in both groups, but no association was found between incontinence and the psychosocial outcome measures. TCA patients perceived themselves as less well adjusted than their matched pairs. Differences between the groups in length of hospitalisation and severity of illness, especially in infancy and early childhood, may account for these differences.

Adolescent↗

Carnitine palmitoyl transferase I and the control of myocardial beta-oxidation flux.

Carnitine palmitoyltransferase I is assumed to be rate limiting for beta-oxidation in all tissues. However, the concentration of malonyl-CoA in heart and muscle is high and is enough to completely inhibit beta-oxidation if this assumption is correct. In this review, we consider whether: (i) there is a malonyl-CoA-insensitive carnitine palmitoyltransferase I activity; (ii) the measured malonyl-CoA concentration in the heart is physiologically meaningful; and (iii) carnitine palmitoyltransferase I is rate-limiting for beta-oxidation in the heart.

Acetyl Coenzyme A↗

Prenatal diagnosis of an ectopic intrathoracic kidney in right-sided congenital diaphragmatic hernia using color Doppler ultrasonography.

The prenatal sonographic features of a fetus with right-sided congenital diaphragmatic hernia diagnosed at 33 weeks are presented. Color Doppler demonstrated an abnormal course of the right renal artery, arising from the aorta and feeding the intrathoracic right kidney. This case report stresses the role of color Doppler in defining which organs have herniated in fetuses with diaphragmatic hernia.

Adult↗

Moderate hypothermia ameliorates liver energy failure after intestinal ischaemia-reperfusion in anaesthetised rats.

BACKGROUND/PURPOSE: Intestinal ischaemia-reperfusion (IR) can cause liver failure. The aims of this work were to study the effects of intestinal IR on liver energy metabolism and to evaluate the effects of moderate hypothermia. METHODS: Intestinal IR (90-minute intestinal ischaemia plus 60-minute or 240-minute reperfusion) was achieved by clamping and unclamping the superior mesenteric artery in rats. Normothermia or moderate hypothermia (30 degrees to 33 degrees C) was maintained by adjusting the environmental temperature. The ratio of hepatic inorganic phosphate to adenosine triphosphate (ATP) was monitored continuously during intestinal IR using in vivo phosphorus ((31)P) magnetic resonance spectroscopy. Phosphorus metabolites also were measured in extracts prepared from freeze-clamped liver and intestine. RESULTS: Mortality occurred exclusively during normothermic intestinal IR. A progressive increase in the hepatic inorganic phosphate to ATP ratio after normothermic intestinal IR was observed. Moderate hypothermia delayed this effect. Analysis of liver extracts confirmed above findings. However, there was no difference in intestinal phosphocreatine or ATP between normothermic and hypothermic rats undergoing intestinal IR. CONCLUSIONS: Intestinal IR at normothermia was associated with liver energy failure and high mortality rate. Moderate hypothermia ameliorated liver energy failure but did not attenuate intestinal energy failure after intestinal IR. Hypothermia may prove to be useful in the management of patients with intestinal IR injuries in the future.

Adenosine Triphosphate↗

Glutamine and glutathione counteract the inhibitory effects of mediators of sepsis in neonatal hepatocytes.

BACKGROUND/PURPOSE: Surgical neonates are at risk of sepsis-associated liver dysfunction. Hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) are important mediators of sepsis, which impair neonatal hepatic metabolism. Glutamine has been shown to have beneficial effects on hepatocyte metabolism during neonatal sepsis. However, the molecular basis of these effects are unknown. The aim of this study was to test the hypotheses that (1) glutamine and its dipeptides counteract the inhibitory effect of septic mediators on neonatal hepatocyte oxygen consumption and (2) the effects of glutamine are specific and not shared by other amino acids. In addition, we wished to determine the metabolic pathways and mediators involved in the action of glutamine. METHODS: Hepatocytes were isolated from suckling rats, and O(2) consumption measured polarographically. Study A: the ability of 10 mmol/L glutamine to reverse the inhibitory effects of 1.5 mmol/L H(2)O(2) and 300 micromol/L S-Nitroso-N-acetylpenicillamine (SNAP; a nitric oxide donor) on O(2) consumption was examined. Study B: the ability of other amino acids and dipeptides of glutamine to reverse the effects of H(2)O(2) was examined. Study C: various concentrations of glutamine were tested for their ability to reverse the H(2)O(2) inhibition of O(2) consumption. Study D: the mechanism of action of glutamine was examined by incubating hepatocytes with either an inhibitor of entry into the Krebs cycle or an inhibitor of glutathione synthesis. Study E: the ability of glutathione to reverse the inhibitory effects of H(2)O(2) was examined. RESULTS: Study A: glutamine reversed the inhibition of hepatocyte O(2) consumption exerted by either H(2)O(2) or NO. Study B: glutamine dipeptides reversed the inhibition of hepatocyte O(2) consumption by H(2)O(2), but other amino acids did not. Study C: the counteracting effect of glutamine was proportional to the dose administered. Study D: blocking entry of glutamine into the Krebs cycle did not abolish the effects of glutamine, but blocking glutathione synthesis completely abolished the effect of glutamine. Study E: exogenous glutathione reversed the inhibitory effect of H(2)O(2) on hepatocyte O(2) consumption. CONCLUSIONS: This study found that glutamine and its dipeptides are unique in reversing the effects of septic mediators on neonatal rat liver oxidative metabolism. The effectiveness of glutamine appears to be mediated via glutathione synthesis. Addition of glutamine, glutamine dipeptides, or glutathione to total parenteral nutrition (TPN) may be beneficial in preventing liver damage in neonatal sepsis.

Animals↗

Additional medical information: prevalence, source, and benefit to parents.

PURPOSE: The aim of this study was to (1) characterize the source of additional medical information acquired by parents and (2) to verify how much information is correctly interpreted and remembered correctly. METHODS: A cross-sectional prospective study was made of parents of 108 children with surgical diseases consecutively admitted to a children's hospital in 1999. The median age of the children was 3 years (range, 0.01 to 16), and that of parents was 34 years (range, 18 to 54). Parental knowledge and understanding of their child's illness, operation, potential operative risk, and long-term outcome were scored on the basis of (1) parents' self appraisal (questionnaire) and (2) objective evaluation (interview) performed by one investigator not involved in the child's care. RESULTS: Parents' education included a university degree (15%), entry examination for university (13%), basic educational qualification (47%), and no educational qualification (15%). Additional medical information was obtained by 77% of the parents (63% from general practitioner, 46% from books, 31% from popular magazines, 24% from internet). Inadequate knowledge of illness and treatment was highlighted in 12% and 19% of the assessment made by interview, respectively, compared with 8% and 14% of the self appraisals. Inadequate knowledge of operative risk was higher in the assessment made by interview (42%) compared with self appraisal (9%; P <.0001). Similarly, inadequate knowledge of long-term outcome was higher in the interview (28%) compared with self appraisal (13%; P <.05). Acquisition of additional medical information irrespective of the source did not affect the accuracy of parental knowledge. Medical knowledge was more accurate in parents of children who required major operations and in those with higher educational qualifications (P <.05). CONCLUSIONS: Parents commonly obtain additional medical information. However, this information does not necessarily improve parents' understanding of the child's operative risk and long-term problems. Parents' perception of having adequate medical information often is incorrect.

Adolescent↗

Colostomy for anorectal anomalies: high incidence of complications.

PURPOSE: The aim of this study was to characterize the type and incidence of complications related to colostomy formation in newborn infants with anorectal anomalies. METHODS: The authors reviewed a 5-year (1994 to 1999) experience of a single institution in the management of neonates with high and intermediate anorectal anomalies who required colostomy at birth. Patients with colostomy still in place have been excluded from the study to maximize the chances of detecting colostomy-related complications. RESULTS: There were 80 neonates with anorectal malformations, of whom, 49 (31 boys and 18 girls) were included in the study. The site of colostomy was sigmoid colon (n = 32), transverse colon (n = 7), and descending colon (n = 10). Thirty-nine colostomies were loop, and the remaining 7 were divided. The median birth weight was 2.96 kg (range, 1.46 to 3.88). The age at colostomy formation was 2 days (range, 1 to 210). Mechanical complications related to colostomy formation were observed in 16 infants (32%) with 3 infants having more than 1 mechanical complication. These included prolapse in 8 (50%), intestinal obstruction (adhesions, intussusception, and volvulus) in 7 (44%), and skin dehiscence in 3 (19%). One neonate had necrotizing enterocolitis (NEC) after colostomy formation. Urinary tract infection was observed after colostomy in 14 infants (29%). The incidence of urinary tract infection was not higher in infants who had loop colostomy (11 of 39, 28%) compared with infants who had divided colostomy (3 of 10, 30%). There were no differences in the incidence of colostomy-related complications and urinary tract infection between male and female infants. There were no deaths in this series. CONCLUSIONS: Formation of colostomy for anorectal anomalies should not be considered a minor procedure. In our experience the incidence of complications after colostomy formation is high. The incidence of urinary tract infections does not seem to be affected by the type of colostomy performed.

Age Factors↗

The clinical significance of thrombocytopenia in neonates with necrotizing enterocolitis.

PURPOSE: The aim of this study was to evaluate the clinical significance of low platelet count in the surgical management of neonates with necrotizing enterocolitis (NEC). METHODS: The clinical course of 58 consecutive neonates with advanced NEC (Bell's stages II or III) treated in the authors' hospital between 1995 and 1998 was reviewed. NEC in neonates who required operation was classified as isolated, multifocal, or pan-intestinal. Severe thrombocytopenia was defined as platelet count less than 100 x 10(9)/L. Rapid fall in platelet count was defined as fall greater than 150 x 10(9)/L within 24 hours to a level less than 100 x 10(9)/L. RESULTS: Median birth weight was 1,564 g (range, 550 to 4,270) and gestational age was 31 weeks (range 23 to 41). Twenty-two neonates (38%) were below 1,000 g. Age at the onset of the disease was 13 days (range, 1 to 62). NEC was treated medically in 7 neonates (12%). Indications for operation included pneumoperitoneum in 23 neonates (45%), clinical deterioration in 19 (37%), and intestinal obstruction in 9 (18%). The nadir platelet count (lowest level during the course of disease) was lower in patients with stage III disease than in patients with stage II disease (P <.05). The greater the extent of the disease, the lower the platelet count (P =.012). The nadir platelet count was lower in infants who died than in survivors (P <.05). None of the patients with platelet count greater than 100 x 10(9)/L died. In predicting intestinal gangrene, severe thrombocytopenia has a sensitivity of 69%, specificity of 60%, and positive predictive value of 89%; rapid fall in platelet count has a sensitivity of 32%, specificity of 89%, and positive predictive value of 92%. CONCLUSIONS: (1) A platelet count less than 100 x 10(9)/L or a rapid fall in platelet count represent poor prognostic factors. (2) Monitoring the platelet count during the course of NEC is useful; however, it cannot be used in isolation to predict the extent of the disease or survival rate.

Birth Weight↗

Continuous enteral feeding impairs gallbladder emptying in infants.

OBJECTIVE: The objective was to test the hypothesis that continuous enteral feeding impairs gallbladder emptying in infants. STUDY DESIGN: A prospective crossover study was performed in 15 infants: (1) bolus enteral feeds were given in phase A, (2) a continuous milk feed was given for 3 days in phase B, and (3) bolus feeds were resumed in phase C. The gallbladder was studied with ultrasonography in phase A, on days 1 and 3 of phase B, and at the start and on days 2 and 4 of phase C. RESULTS: Baseline volume was 116.1 mm(3) (range, 48.1 to 374.8 mm(3)) in phase A and 293.3 mm(3) (range, 109.4 to 1134.9 mm(3)) (P <.001) after 3 days of phase B; it returned to the phase A value after 4 days of phase C. The contraction index was 65.2% (range, 40.6% to 78.2%) in phase A and 1.7% (range, 0% to 8.4%) (P <.001) after 3 days of phase B. It returned to its phase A value immediately after bolus enteral feeds were resumed in phase C. CONCLUSIONS: Continuous enteral feeding leads to an enlarged, noncontractile gallbladder in infants. Emptying is observed immediately after bolus feeds are resumed, and volume returns to baseline after 4 days. The mode of feeding has important bearings on the motility of the extrahepatic biliary tree.

Cross-Over Studies↗