Effect of probiotics on enterocyte bacterial translocation in vitro

 Enteral probiotics such as Lactobacillus casei GG (LGG) have been used in the treatment of a variety of intestinal disorders in infants and children, including diarrhea, malabsorption, and Clostridium difficile colitis. We have previously demonstrated that the probiotic bacterium LGG has an inhibitory effect on bacterial translocation (BT) in a neonatal rabbit model. However, this in-vivo model is limited for investigating the cellular and molecular mechanisms responsible for probiotic inhibition of BT. The purpose of this study was to determine the efficacy of LGG in reducing the rate of Escherichia coliC25 (E. coli C25) translocation using an in-vitro enterocyte cell-culture model. Human colonic carcinoma (Caco-2) enterocytes were seeded in porous filters in the apical chamber of a two-chamber cell- culture system and grown for 14 days to confluence. The monolayers were incubated at 37 °C with LGG for 180 min. Non-adherent LGG was washed away prior to a 120-min incubation period with 10⁵ CFU E. coli C25. E. coli that had translocated across the enterocyte monolayer were quantified by growing basal-chamber media samples on gram-negative bacteria-specific MacConkey's agar. In order to determine monolayer integrity, transepithelial electrical resistance (TEER) was measured across Caco-2 cells treated with LGG and E. coli. Statistical analysis was by ANOVA with P < 0.05 considered significant. LGG inhibited E. coli translocation at all LGG concentrations tested. The TEER ratio was not significantly altered by addition of LGG or E. coli (0.9 ± 0.03 vs 0.8 ± 0.05). These results demonstrate that the probiotic bacterium LGG inhibits BT of E. coli C25 in a dose-dependent manner in an in-vitro cell-culture model. This model should be valuable in investigating the cellular and molecular mechanisms involved in the inhibition of pathological enteral bacteria by probiotic agents.     

Effect of secretory immunoglobulin A on bacterial translocation in an enterocyte-lymphocyte co-culture model

 Intestinal secretory immunoglobulin A (sIgA) plays an important role in gut mucosal immunity in vivo; however, in-vitro enterocyte models for studying the mechanisms of these effects are lacking. This study utilizes a cell-culture model to investigate the effect of sIgA on bacterial translocation (BT) across human enterocytes co-cultured with human lymphoid cells (Raji cells). This model is intended to mimic in-vivo enterocyte/lymphocyte interactions found in intestinal follicle-associated epithelia. Human Caco-2 enterocytes were grown to confluence on porous filters in the apical chamber of a two-chamber cell-culture system. After differentiation, human B lymphoid cells (Raji cells) were added to the basolateral surface of Caco-2 monolayers for 3 days' co-culture, followed by washing away of unincorporated Raji cells. Transepithelial electrical resistance (TEER) was used to measure tight-junction permeability. Monolayers were treated with or without sIgA, IgG (negative control), or mannose (positive control). BT across the cell monolayer was determined 1.5 h after addition of Escherichia coli. Statistical analysis was by the Kruskal–Wallis test, P below 0.05 considered significant. In co-culture monolayers treated with sIgA, IgG, or mannose, there was no significant effect on TEER; however, the magnitude of BT across cells treated with sIgA (1.3 ± 0.4 log₁₀CFU/ml) and mannose (1.6 ± 1.1 log₁₀CFU/ml) was significantly decreased compared to PBS (3.9 ± 0.4 log₁₀CFU/ml) and IgG (2.9 ± 0.6 log₁₀CFU/ml) controls (P < 0.05). sIgA BT inhibition was dose-dependent. BT inhibition by sIgA and mannose was additive (0.5 ± 1 log₁₀CFU/ml). Inhibition of BT was negated when sIgA and mannose were removed by washing prior to E. Coli addition (3.6 ± 0.5 log₁₀CFU/ml), suggesting that both inhibitors act through bacterial binding.     

The effects of intravenous epidermal growth factor on bacterial translocation and central venous catheter infection in the rat total parenteral nutrition model

 Sepsis is a major complication of total parenteral nutrition (TPN) in children. Gut mucosal atrophy (GMA) and bacterial translocation (BT) occur in patients receiving TPN, and the translocated enteric organisms may cause central venous catheter (CVC) infection. Epidermal growth factor (EGF) has a trophic effect on the gut mucosa and may reduce BT, thereby reducing catheter infection. Using a rat TPN model, the relationship between GMA, BT, and catheter sepsis was examined and the effect on these of intravenous EGF was studied. There were four experimental groups. Group 1 had no CVC, Groups 2, 3, and 4 had a continuous central venous infusion as follows: group 2, saline; group 3, TPN; group 4, TPN with EGF. Groups 1 and 2 had free access to chow, groups 3 and 4 had no enteral feeds. After killing at 1 week, blood, tissue, and catheter specimens were cultured and mucosal morphology analysed. BT was defined as the presence of the same organism in cultures from the gut lumen and mesenteric lymph nodes (MLN). TPN only (group 3) resulted in GMA and BT, and 5 of 12 animals with BT had the same gut bacteria in blood and/or catheter cultures. The addition of EGF to the TPN significantly reduced GMA, BT to the MLN, and blood and/or catheter infections (P =< 0.05). In animals carrying enterococci, there was a significant reduction in translocation of enterococci (group 3: 8/14; group 4: 0/11; P < 0.05) and catheter infection by enterococci was prevented (group 3: 3/14; group 4: 0/11). EGF thus reduced GMA, BT, and blood and/or catheter infection when given IV to rats receiving TPN. Enterococcal translocation and subsequent blood and/or catheter infection was completely prevented, suggesting a selective effect of EGF. Accepted: 13 December 1999     

Bacterial translocation in the newborn rabbit: effect of age on frequency of translocation

Sepsis is a significant cause of morbidity and mortality in neonates, and in a significant number of cases no predisposing factors can be identified. We hypothesize that bacterial translocation (BT) may be the etiology of neonatal sepsis when no source is identified. Mesenteric lymph nodes (MLN), spleen (SPL), and liver (LIV) were harvested from 36 rabbit pups ranging in age from 4 to 24 days and divided into three groups based on their age: group I, 4–6 days; group II, 13–15 days; and group III, 22–24 days. Tissues from each organ were homogenized and placed in both aerobic and anaerobic environments. After 48 h the number of colony-forming units/g tissue was identified. The total percentage of positive growth was significantly higher in group I for MLN (33%) and LIV (23%) when compared to groups II and III (<4% for both groups). Gram-negative growth (as selected by MacConkey [MC] media) was significantly higher in all tissue specimens from group I (MLN + 35%, SPL = 20%, LIV = 25%) compared to groups II and III (0% growth in all MC plates, P <0.01). These data support the hypothesis that spontaneous BT occurs with significant frequency in the neonate.     

The effect of phospholipase A2 on bacterial translocation in a cell culture model

 The activity of phospholipase (PL)A₂ is elevated in the intestinal epithelia of patients with inflammatory bowel disease (IBD). Recently, we reported that lysophosphatidylcholine (L-PC), the PLA₂ hydrolysis product of phosphatidylcholine (PC), stimulates bacterial translocation (BT) in an enterocyte cell-culture model. These two observations stimulated us to examine the effects of extracellular PLA₂ on intestinal epithelial permeability. Human Caco-2 enterocytes were grown to confluence on porous filters in the apical chamber of a two-chamber cell-culture system. Monolayer integrity and tight-junction permeability were measured by dextran blue (DB) permeability and transepithelial electric resistance (TEER). Monolayers were treated with PC, L-PC, or PLA₂ with and without PC. The magnitude of BT was determined 2 h after treatment by adding Escherichia coli to the apical chamber followed by quantitatively culturing basal chamber samples. Thin-layer chromatography (TLC) was utilized to verify PLA₂ hydrolysis of PC to L-PC. Statistical analysis was performed by one-way analysis of variance. The magnitude of BT across monolayers pretreated with PLA₂ + PC significantly increased compared to either PC or PLA₂ (6.83 ± 0.069, 2.41 ± 0.46, and 3.06 ± 1.14 log10 colony forming units/ml, respectively, P < 0.05). Absence of DB-permeability in any group confirmed monolayer integrity. TLC of PL samples harvested from the apical monolayer surface confirmed PC hydrolysis. PLA₂ mediates hydrolysis of PC to L-PC when both are applied to the apical surface of cultured enterocyte monolayers, resulting in increased BT and increased TEER with no damage to monolayer integrity. These observations may have implications in the pathogenesis and treatment strategies for IBD.     

Respiratory distress in a neonate with an enlarged thymus

 Thymic hyperplasia, although not a rare condition in infancy, is usually asymptomatic. We describe an infant presenting in the perinatal period with marked tachypnoea. An enlarged thymus, demonstrated on chest radiograph and CT, was associated with small-volume, non-compliant lungs. Other causes of pulmonary malfunction and maldevelopment were excluded. Conclusion Thymic enlargement is unusually associated with neonatal respiratory distress but should be considered in the differential diagnosis. Received: 9 March 1999 and in revised form: 7 July 1999 / Accepted: 31 August 1999     

Life-threatening mediastinal teratoma in a neonate

 This report describes a newborn with a large mediastinal teratoma (MT) presenting with severe respiratory distress (RD) at birth. At operation, there was no space for dissection because the huge cystic and solid tumor completely occupied the left hemithorax. After evacuation of the cystic component, the tumor was removed successfully. To our knowledge, only 16 newborn infants with MT presenting with RD have been reported. Operative morbidities occurred in one-half of the cases. We have reviewed the literature to discuss the potential risks of this entity. Accepted: 17 February 2000     

微生态制剂防治新生儿坏死性小肠结肠炎病例对照研究

目的：探讨新生儿坏死性小肠结肠炎(NEC)的危险因素及应用微生态制剂(培菲康)预防NEC发生的有效性。方法：对2002年1月至2005年5月住院治疗的2528例新生儿分为微生态制剂预防组与非预防组,观察两组NEC的发病率;以确诊NEC的患儿为病例组,非NEC新生儿为对照组进行病例对照研究。结果：预防组1182例中6例诊断为NEC,发病率0.51%;非预防组1346例中19例发生NEC,发病率为1.41%,两组差异具有显著性(P<0.05)。条件Logistic回归分析提示:胎龄、新生儿缺氧缺血性脑病、败血症及病情危重程度是危险因素;微生态制剂的应用是保护因素。结论：避免NEC的危险因素,预防性应用微生态制剂能够降低NEC发病率。     

Lack of effectiveness of dexamethasone in neonatal bacterial meningitis

A clinical trial was conducted to determine whether dexamethasone as adjunctive therapy alters the outcome of bacterial meningitis in neonates. Fifty-two full-term neonates with bacterial meningitis were enrolled in a prospective study. Infants were alternately assigned to receive either dexamethasone or not. Twenty-seven received dexamethasone in addition to standard antibiotic treatment and 25 received antibiotics alone. Dexamethasone therapy was started 10–15 min before the first dose of antibiotics in a dose of 0.15 mg/kg per 6 h for 4 days. Baseline characteristics, clinical and laboratory features in the two groups were virtually similar. Both groups showed a similar clinical response and similar frequency of mortality and sequelae. Six (22%) babies in the treatment group died compared to 7 (28%) in the control group (P = 0.87). At follow up examinations up to the age of 2 years, 6 (30%) of dexamethasone recipients and 7 (39%) of the control group had mild or moderate/severe neurological sequelae. Audiological sequelae were seen in two neonates in the dexamethasone group compared to one in the control group. Conclusion Adjunctive dexamethasone therapy does not improve the outcome of neonatal bacterial meningitis. Received: 22 December 1997 / Accepted: 14 March 1998     

Renal injury in perinatal hypoxia: ultrasonography and changes in renal function

 We studied 12 hypoxaemic neonates (5 mature newborns, birth weight 2850–4200 g, gestational age 37–41 weeks; and 7 premature newborns, birth weight 770–1850 g, gestational age 27–34 weeks;) with repeated urine and blood chemistry on the 1st and 3rd days of life. Nephrosonographical examinations on the 1st, 3rd and 5–7th days of life were also performed. As controls, 12 healthy infants were examined (gestational age 36–42 weeks; birth weight 2450–4200 g). Hypoxic neonates had higher serum creatinine and blood urea nitrogen levels. Tubular markers also demonstrated renal tubular damage. Neonates in both hypoxic groups were hyperuricaemic and hyperuricosuric, and had higher urinary protein concentrations. All these infants exhibited an increased echogenicity of the renal cortex, and 11/12 showed the same finding in the medullary area. These findings disappeared within 1 week in all infants. Among the 12 healthy control infants, no cortical hyperechogenicity was found and only three of these infants displayed transient medullary renal hyperechogenicity. Conclusion Since the hypoxaemic infants demonstrated greatly increased urinary concentrations of uric acid and protein, we suggest that a temporary precipitation of these two agents may be responsible for the ultrasonographic findings. Circulatory redistribution might play a role in the phenomenon of cortical hyperechogenicity. Received: 23 March 2000 / Accepted: 14 March 2001     

Intrapericardial lymphangioma presenting as neonatal cardiac tamponade

We report a unique case of cardiac tamponade in a newborn due to an intrapericardial lymphangioma. Echocardiography and magnetic resonance imaging suggested that the mass, which was situated between the right atrium and the aortic root, was unsuitable for primary resection. A pericardial window was performed, and over the next 16 months the tumor spontaneously regressed.     

Techniques available for the management of massive sacrococcygeal teratomas

 An infant born in the 34th week of gestation weighing 5,355 g with a massive sacrococcygeal (SC) tumor was delivered by elective cesarean section. An ultrasonographic examination showed solid and cystic components in the tumor. Resection was successfully undertaken with insertion of a Nélaton catheter into the rectum to avoid unnecessary impairment of the viscera. The tumor weighed 2,380 g, measured 25 × 14 × 11 cm, and was clinicopathologically diagnosed to be a SC teratoma. This experience and other publications show that several considerations including control of hemorrhage and coagulopathies, visceral protection, and avoidance of wound infection are necessary to facilitate the surgical management of massive SC tumors. Several suggestions are made concerning the pre- and intraoperative management of this rare tumor. Accepted: 10 January 2000     

Emergency neonatal surgery in a developing country

 With better understanding of neonatal physiology and improvements in diagnostic facilities and neonatal intensive care units (NICU), the outcome of neonatal surgery has improved in developed countries. In developing countries, however, neonatal surgery is problematic, particularly in the emergency setting, but there are few reports from these countries. A retrospective analysis of 154 neonates who had emergency surgery over a 10-year period at the Ahmadu Bello University Teaching Hospital, Zaria, Nigeria, was undertaken. Emergency surgery represented 40% of surgical procedures in neonates in the hospital. The majority of the patients (94.8%) were delivered at home or in rural health centers. The median weight was 2.7 kg (range 2.0–3.7 kg). In 89 cases (58%) the indications for surgery were intestinal obstruction, anorectal malformations in 60(67%) and in 33(21%) complicated exomphalos or gastroschisis. Nine patients (6%) required surgery for ruptured neural-tube defects. A colostomy was the commonest procedure (51, 33%), 27(53%) of which were performed using a local anesthetic without adverse effects. Thirty-three abdominal-wall defects were closed by various methods (fascial closure 23, skin closure 6, improvised silo 4). Overall, 37 (24%) procedures were performed using local anesthesia. Fifty-nine patients (38%) developed postoperative complications (infections 33, respiratory insufficiency 16, colostomy complications 8, anastomotic leak 2). The mortality was 30.5%, 66% due to overwhelming infection, 28% to respiratory insufficiency, and 4.3% to multiple anomalies. Other factors considered to have contributed to morbidity and mortality were late referral and presentation and a lack of NICUs. Thus, emergency neonatal surgery is attended by high morbidity and mortality in our environment at the present time. Early referral and presentation and provision of NICUs should improve the outcome. Accepted: 3 August 2000     

血清C-反应蛋白和唾液酸联合测定在新生儿细菌感染性疾病中的意义

目的 探讨血清Ｃ－反应蛋白（ＣＲＰ）和唾液酸（ＳＡ）联合测定在新生儿早期细菌感染诊断和疗效观察中的意义。方法 同时测定５２例起病在１周内的细菌感染新生儿血清ＣＲＰ和ＳＡ水平。结果 ＣＲＰ在起病２４ｈ内即增加到（６８．３±３２．８）ｍｇ／Ｌ,与正常对照组[（０．７８±０．２５）ｍｇ／Ｌ］相比差异具有显著性（Ｐ＜０．０１）,当炎症得到一定控制后则明显下降（Ｐ＜ ０．０１）。ＳＡ在起病２４ ｈ内逐渐增加,至１～３ ｄ和４～７ ｄ时分别升至（１．８８±０．８５）,（２．９５±０．８７）ｍｍｏｌ／Ｌ,与对照组[（０．９１±０．４０）ｍｍｏｌ／Ｌ］比较差异具有显著性意义（Ｐ＜ ０．０１）,当感染得到完全控制时可降至正常对照水平。结论 血清ＣＲＰ和ＳＡ的联合测定,有助于提高新生儿早期细菌感染性疾病的诊疗水平。     

Cystic rectal duplication: a rare cause of neonatal bladder-outlet obstruction and hydronephrosis

 A case of cystic rectal duplication (RD) is presented. A 7-day-old female was admitted with acute urinary retention, voiding difficulty, and abdominal distention since she was 4 days of age. Ultrasound and abdominal computed tomography (CT) demonstrated a huge, cystic mass in the pelvis and abdomen that resulted in acute urinary retention and bilateral hydronephrosis. CT-guided drainage of the lesion followed by transabdominal surgical excision resulted in a cure. Pathologic examination demonstrated a RD lined by respiratory epithelium. Accepted: 14 December 1999     

A review of teicoplanin in the treatment of serious neonatal infections

Gram-positive bacteria, notably coagulase negative staphylococci, have become an important cause of infection in neonates. Furthermore, many of these pathogens are now resistant to multiple antibacterial agents. Teicoplanin, a glycopeptide antibiotic, is active against a broad range of Gram-positive pathogens, including methicillin-resistant staphylococci. It has advantages over vancomycin in terms of tolerability, with a lower propensity to cause nephrotoxicity and anaphylactoid-like reactions, and in terms of ease of administration and monitoring requirements. The clinical utility of teicoplanin in neonates with Gram-positive infections has been investigated in several noncomparative studies. Clinical and bacteriological response rates in 173 neonates treated with teicoplanin 8–10 mg/kg intravenously or intramuscularly once daily after a loading-dose regimen of 10–20 mg/kg per day have ranged from 80%–100% and 83%–100%, respectively. Few adverse events related to teicoplanin have been reported in this patient population. Conclusion Teicoplanin (8–10 mg/kg) administered intravenously or intramuscularly once daily after a loading-dose regimen of 15–20 mg/kg per day appears to be an effective and well tolerated treatment for Gram-positive infections in neonates. Received: 4 November 1995 / Accepted: 30 August 1996     

Mechanism of impaired immunologic response to bacterial antigens in burn wounds in children

Material was obtained from necrotic tissue excised from burn wounds in 60 children and examined immunohistochemically for the percentages of CD3, CD4, CD8, CD20, and CD68 cells. The results were then correlated with the burn surface area (BSA). Bacteriologic studies revealed the presence of bacteria in only 22 wounds with BSA greater than 10% of total body surface area. In this group, the proportion of CD3, CD4, CD8, CD20, and CD68 cells was correlated with the severity of infection, measured as the number of bacteria per g tissue. The results showed a positive correlation between the BSA and the percentage of CD8 cells (P < 0.001) and a negative correlation between CD4 cells and BSA (P < 0.02). The correlation between CD4/CD8 index and BSA was significantly negative. Likewise, a significant negative correlation was also noted between the percentage of CD4 and CD8 cells within the wound (P < 0.001). The severity of infection (bacteria/g tissue) was also positively correlated with the percentage of CD8 cells (P < 0.05) and negatively with the percentage of CD4 cells (P < 0.05). The correlation between CD4/CD8 index and intensity of infection was also highly significant. The results obtained show that in extensive burn wounds bacterial antigens may not be recognized properly due to the decreased percentage of CD4 cells and increased percentage of CD8 cells, which enhances bacterial growth in these wounds. Accepted: 12 July 1999     

Effects of male sex hormones on urodynamics in childhood: intersex patients are a natural model

 The effects of sex hormones on bladder function have been evaluated in adult females, especially in regard to postmenopausal incontinence and bladder irritability syndromes. These have not been investigated in children in regard to urodynamic findings. An intersex patient whose bladder is under the influence of androgens is a natural model to investigate the effects of male sex hormones on bladder function in females. To evaluate the urodynamic findings and clinical symptoms in a group of intersex patients and to determine how androgens influence bladder function in female children, clinical and urodynamic records of 12 intersex patients with adrenogenital syndrome were investigated retrospectively. The mean age was 9 ± 5.7 years (1.5–18) and the mean follow-up period was 5.1 ± 4.4 years (1–12). Congenital adrenal hyperplasia (CAH) was present in all cases. Only 3 patients had urinary symptoms and incontinence, but these findings did not correlate with their urodynamic findings. None of the patients required medications for their urinary symptoms. Nine are still being treated medically by the pediatric endocrine team with hydrocortisone for CAH. The upper urinary tract was found to be normal with no hydronephrosis. The mean bladder capacity (269 ± 122 ml) was lower (86.7%) than the estimated capacity for age. The mean compliance was 20 ± 13.7 ml/cmH₂O. No unstable detrusor contractions were encountered. The most remarkable finding was this reduced bladder capacity of androgenized female patients for age, which shows the antagonistic effect of androgens on bladder urodynamics in females. Accepted: 11 January 2000     

益生菌治疗反复呼吸道感染的相关机制

反复呼吸道感染是儿童常见的慢性呼吸道疾病,发病机制复杂,病因及治疗方法较多.益生菌是近年来临床应用较多的免疫调节剂之一,本文综述了反复呼吸道感染患儿肠道菌群的变化,并从调节肠道菌群、增强肠黏膜屏障、刺激肠道黏膜生长、调节机体免疫等方面阐述了益生菌治疗反复呼吸道感染的相关机制.     

Tissue antioxidant capacity and bacterial translocation under total parenteral nutrition

 Alterations in the antioxidative system have been observed during total parenteral nutrition (TPN). Light exposure or changes in the composition of TPN formulas may affect this system. Bacterial translocation (BT) is frequent under TPN and may be related to oxidative status. The aim of this study was to determine the adverse effects of standard and glutamine-enriched TPN, with or without light exposure, on oxidative status (liver and kidney-reduced glutathione, GSH) and its relationship to BT. Thirty-three adult Wistar rats underwent central-venous cannulation and were randomly assigned to one of four groups receiving different TPN regimes for 10 days. The TPN group (n=10) had standard TPN, the TPN(-) group (n=8) standard TPN without light exposure, the GTPN group (n=8) glutamine-enriched TPN, and the GTPN(-) group (n=7) glutamine-enriched TPN without light exposure. A sham group (n=16) receiving chow and water ad libitum and saline i.v. served as controls. At the end of the experiment, GSH was determined in liver and kidney tissue. Mesenteric lymph nodes and peripheral and portal blood samples were cultured for BT. Compared to sham rats, TPN groups had statistically significant lower GSH levels, but there were no differences between standard or glutamine-enriched groups or light-exposure groups. Sham animals had 12% BT. Significantly higher BT (P < 0.05) occurred in TPN rats: 70% in the TPN group, 88% in the TPN(-) group, 86% in GTPN (-) animals, and only 50% in the GTPN group (P=0.06 vs TPN group). In conclusion, (1) TPN reduces antioxidant capacity; (2) glutamine supplementation or light protection does not improve tissue antioxidant capacity under TPN; (3) the absence of light exposure does not improve TPN-related BT; and (4) glutamine supplementation tends to reduce BT only in the presence of light.