[Training in laparoscopy and appendicitis]

BACKGROUND

In order to improve laparoscopic skills, appendectomy is the most common procedure because of its high frequency and low difficulty. In spite of that, during the learning curve (each surgeon´s first 35 interventions) the incidence of complications may increase, so improvement in training means a bigger risk for some patients.

METHODS

We retrospectively reviewed major complications (intra-abdominal abscess, intestinal occlusion, hemorrhage) of 1,710 appendectomies performed at our service between 1997 and 2013. We divided them in three groups: open appendectomy (OA, n= 1,258), laparoscopic appendectomy during the learning curve (LDC, n= 154) and laparoscopic appendectomy after the learning curve (LAC, n= 298). In addition, we distinguish between simple appendicitis (n= 1,233) and peritonitis (n= 477).

RESULTS

In the OA group we detected110/1,258 major complications (8.7%), 28/154 major complications (18.2%) in the LDC group and 19/298 (6.4%) in the LAC group (p<0.05 LDC vs OA and LAC). In the simple appendicitis group, we found 13/889 major complications (1.5%) in OA, 3/115 (2.6%) in LDC group and 2/229 (0.9%) in LAC group (p= ns LDC vs OA and LAC). In the peritonitis group, 97/369 (26.3%) major complications were found in OA group, 25/39 (64%) in LDC group and 17/69 (24.6%) in LAC group (p<0.05 LDC vs OA and LAC).

CONCLUSIONS

Educational purpose laparoscopic appendectomy must be used in simple appendicitis cases.

[Management of appendicular mass]

BACKGROUND

Management of appendicular mass is still controversial. Some authors plead for an initial non-operative approach followed by a delayed appendectomy.

OBJECTIVES

Our aim has been to revise the usefulness of this management and the optimal time to carry out the appendectomy.

METHODS

We made a retrospective review of all the appendicular mass cases treated in our hospital during the last 8 years. We analyzed the success rate of the non-operative approach, the interval until the delayed appendectomy was performed, difficulty found at surgery and the occurred complications.

RESULTS

Our series includes 19 appendicular mass cases managed initially by a non-operative approach. Intravenous antibiotics were administered to all of them and in 14 cases a peritoneal drainage was placed (the average length of stay was of 11.5 days). In 3 cases (16%) early appendectomy was performed (12, 30 and 40 days after the onset of the symptoms). In 16 (84%) the conservative approach succeeded and the appendectomy was delayed 3-12 months (average: 6.6 months). Four of them were performed by an open approach and 12 by laparoscopy (in 3 of which conversion was needed). The average length of stay was of 1.8 days, with only one complication (wound abscess). Of these 16 delayed appendectomies, 11 were not technically difficult to perform (average wait of 5.5 months) and in 5 cases the procedure was difficult due to multiple adhesions (average wait of 9.4 months).

CONCLUSION

Conservative management of appendicular mass is useful, with a success rate of 84% in our series. The appendectomy was less hazardous if performed 3-6 months after the onset of the symptoms.

[Biodegradable catheters for fistula prevention in hypospadias. Experimental preliminary study]

INTRODUCTION

Continuous technical innovations are not enough to resolve the high incidence of fistula after hypospadias repair. A urethral catheter-tutor made of reabsorbable polymeric biomaterial (RPB) which could be left in situ long enough could reduce the complications.

TARGET

To investigate in an animal model differents RPB to be used in urology.

METHODOLOGY

CRL Wistar rats, males, divided into 5 equal groups according to the used polymers: polylactide; lactic-coprolactone copolymer; lactic-glycolic copolymer; simulated; control silicones. Three individuals were sacrificed per group at 4th, 10th and 16th week. In all animals (exceptuating the simulated group), biomaterial was fixed to the bladder wall bylaparotomy. Animals remained in individual housing and kept under daily control of hematuria during the first 15 days and weekly weight and urine control for pH and lactate. After being slaughtered, remaining polymer was collected for chemical analysis and bladder tissue for hystologic study.

RESULTS

There was no mortality, hematuria nor other clinical signs. The bladder wall showed a mild foreign body reaction. The values of lactate and pH in urine did not reach toxic levels. Lactic-glycolic was totally reabsorbed by the 10th week and had the lowest degree of calcification. Polylactide and lactic-coprolactone remained intact.

CONCLUSION

The model of urinary bladder has proven useful for studying the degradation of bioresorbable polymers. The analyzed polymers have spent long time to be reabsorbed, so we will have to study new others.

[Adaptation in the small intestine: Effect of minimal enteral nutrition and probiotics on proliferation and apoptosis in the intestinal wall]

BACKGROUND

The intestinal wall integrity is central to the barrier function and depends on the balance of proliferation/apoptosis. Short bowel (SB) or Parenteral Nutrition (PN) induce high bacterial translocation (BT) probably by the intestinal barrier bug. Probiotics or minimal enteral nutrition (MEN) have reduced BT in animal models.

OBJECTIVE

Determine in two BT animal models (SB or PN) the effect of MEN or probiotics on proliferation and apoptosis rates of the intestinal wall.

METHODS

Seventy-one Wistar rats, divided into 4 groups: 1) PN (N = 23): parenteral nutrition; 2) PNMEN (N = 16): PN + MEN (2.9 g/100 g/day standard diet); 3) RES (N = 15): 80% bowel resection and standard oral diet; 4) RESPROB (N = 17): RES + probiotics (7 X 10(9) CFU Bifidobacterium lactis). After 10 days in metabolic cages, mesenteryc lymph nodes, portal blood and peripheral blood were cultured. By immunohistochemistry, proliferation and apoptosis index were calculated as well as the proliferation-apoptosis rate.

RESULTS

BT: decreased in PNMEN (45%) and RESPROB groups (35%) versus PN (65%) and RES (67%) groups (p<0.05). Proliferation index: was better in PNMEN (12,07) and RESPROB (13,93) groups than PN (7,45) and RES (5,54) groups. (p</0.05). Apoptosis index: PNMEN group had 7,81 and PN group 14,90. (p<0,05). Proliferation-apoptosis rate: was higher in PNMEN (1,54) and RESPROB (1,67) groups than PN (0,50) ans RES (0,71) groups. (p<0.01).

CONCLUSIONS

MEN and probiotics reduce BT and improve cellular renewal by encouraging the proliferation. MEN also prevents apoptosis.

[Detection of bacterial translocation by polymerase chain reaction in an experimental short bowel model]

BACKGROUND

Bacterial overgrowth occuring after massive bowel resection, facilitates Gram-negative intestinal Bacterial Translocation (TB). Probiotic agents might have beneficial effects on TB. On the other hand, polymerase chain-reaction (PCR) has better sensitivity than conventional methods for bacterial detection and has not been investigated in experimental models of short bowel syndrome and TB.

OBJECTIVE

To test the hypothesis that the administration of Bifidobacterium lactis (BL) decreases Escherichia coli Bacterial Translocation (ECTB) in experimental short bowel syndrome and to confirm the better sensitivity of PCR technique to detect ECTB.

METHODS

Adult Wistar rats, orally fed with standard rat chow and tap water "ad libitum", were maintained in individual metabolic cages for ten days and divided into three groups: Control (n = 15): non-manipulated animals. RES (n = 15): 80% gut resection. Daily administration 1 ml of sterile water, after orogastric intubation. RES-PRO (n = 18): same resection and daily administration of 7.8 x10(9) Bifidobacterium lactis Colony Forming Units (CFU). At the end of the experiment, mesenteric lymph nodes (MLN), and both peripheral and portal blood samples were recovered and cultured by standard procedures. Also, genomic DNA from E. coli was detected by PCR technique.

RESULTS

By conventional cultures ECTB was detected in 0% in the control group, 73% in the RES group and 33% in the RES-PRO group. PCR technique detected ECTB in 47% of the control group, 87% of the RES group and 33% of RES-PRO group, showing higher sensitivity. By both methods, animals receiving BL (RES-PRO group) showed less ECTB. By conventional culture, the relative risk (RR) was 0.45 (95% CI 0,22-0,79) and the number needed to treat (NNT) was 3 (95% CI 0-11). By PCR technique, the RR was 0.38 (95% CI 0.19-0.76), and the NNT 2 (95% CI 0-4).

CONCLUSIONS

1) Administration of Bifidobacterium lactis reduces the incidence of ECTB. 2) PCR technique is a more sensitive method for ECTB detection.

[Laparoscopic appendectomy after the learning curve]

BACKGROUND

Despite its increasing popularity, laparoscopic appendectomy does not put an unanimous end to the answer to the best treatment for appendicitis. Although the postoperative stay is shorter, the wound infection practically does not exist and scars are minimal, some publications question its advantages due to the incidence of intra-abdominal absceses, postoperative analgesia requirements and the recently described "postlaparoscopic appendectomy complication" (PLAC), an intra-abdominal infection, without abscess formation, which develops after laparoscopic appendectomy for non-complicated appendicitis. Some of this series include the "learning curve", wherein they compare results of inexperienced surgeons in laparoscopic techniques with those obtained after with the firmly established open appendectomy (OA) technique. With the aim to clarify this aspects, we reviewed our experience in laparoscopic appendectomy during (LDC) and after (LAC) the "learning curve" and we compared their complications with the open appendectomies' ones.

METHODS

We retrospectively reviewed 807 appendectomies: 208 laparoscopic (LA) and 599 open (OA) from January 2001 to December 2007 performed in our hospital. In the laparoscopic group, 83 of them (40%) were done during the learning curve (each surgeon's 35 first interventions, LDC) and 125 (60%) after the learning curve (LAC). We have compared both laparoscopic subgroups to each other and to the open appendectomies group. We analysed the age, sex, length of stay, kind of appendicitis (simple or perforated appendicitis) and five of the most serious complications: intra-abdominal abscess, postoperative intestinal occlusion, intestinal perforation, haemorrhage and PLAC.

RESULTS

The mean age (9 years), sex (58% men; 42% women) and the peritonitis rate (30%) were similar among the 3 groups. The mean length of stay was reduced from 5.4 days in OA group to 4.2 days in LA group and 3.6 days in LAC group (p < 0.01). The simple appendicitis cases had the shortest length of stay: 3.41 days in OA group and 2.16 days in LA group (p < 0.0001). There were no differences in stay for the peritonitis group. In the OA group, we detected 56 severe complications (9,3%): 49 abcesses, 2 occlusions, 2 PLAC, 1 haemorrhage, 1 intestinal perforation and 1 liver abscess. Nineteen severe complications were found in LDC group (22,9%): 9 abscesses, 4 occlusions, 4 haemorrhages, 1 intestinal perforation and 1 PLAC (p < 0.01 vs OA group). In the LAC group, we found 13 complications (10,4%): 9 abscesses, 1 occlusion, 1 PLAC and 2 haemorrhages (p = 0.3 vs OA group).

CONCLUSIONS

1. The length of stay was significantly reduced in laparoscopic appendectomies. 2. Severe complications, particularly intestinal occlusions and haemorrhages, increased significantly during the learning curve, with a slight fluctuation for intra-abdominal abscesses and PLAC. 3. After the learning curve, complications' global rate was similar to the OA group's, with an increment of haemorrhages and occlusions, no variation for PLAC and a slight reduction for intra-abdominal abscesses. 4. In our experience, laparoscopic appendectomy after the learning curve is the best therapeutic option for acute appendicitis.

[Short bowel syndrome in the research setting: 15 years' experience]

The fight against infection and liver disease associated with parenteral nutrition (PN) are surely two of the most problematic aspects in the management of paediatric patients with short bowel syndrome (SBS). In the Research Unit of Donostia Hospital, we have spent the past 15 years investigating different ways of reducing these complications in an experimental model of short bowel in the Wistar rat (resection of 80% of the small bowel, with and without PN). All the experiments had a duration of 10 days and 323 animals reached the end of the study period. Nine groups were established in which some type of intervention was performed, and there were 8 control groups. The interventions were: 3 dietary (minimal enteral nutrition [MEN] with low or high dose probiotics); 5 pharmacological (administration of growth hormone [GH], epidermal growth factor [EGF], insulin, cholecystokinin [CCK], and selective intestinal decontamination [SID]); and 1 surgical (resection of the ileocaecal valve). Infection due to bacterial translocation (BT) was detected by culture of mesenteric lymph nodes, portal blood and peripheral blood, and liver damage by the levels of proinflammatory cytokines (IL-1 and TNF-alpha). In summary, our results are: Probiotics, MEN and SID reduce BT. Liver damage was milder in the groups with MEN, SID and CCK. The groups receiving GH, EGF or insulin presented a higher incidence of BT. BT was lower after resection of the ileocaecal valve. In conclusion, the probiotics, MEN and CCK could be useful in the management of children with SBS. These data confirm the utility of this experimental model of short bowel for the investigation of different aspects of SBS.

[Currarino syndrome]

The Currarino syndrome is a form of caudal regression syndrome characterized by the classic triad of presacral mass, sacral bone defect and anorectal malformation in which an autosomal dominant inheritance has been described. In case of clinical suspicion it is necessary to search for the classic alterations and to detect other possible associated malformations in order to avoid complications. The management is multidisciplinary and depends on the type of alterations that the patient has. We report a 17-month-old female baby that initially passed unnoticed and was detected during a rectoplasty for reconstruction of a rectal stenosis. The baby presented complications derived from ignorance of the existence of a presacral mass. Early diagnose and adequate treatment is very important.

[Effect of the administration of cholecystokinin on the cholestasis associated with total parenteral nutrition in experimental short bowel]

INTRODUCTION

Total parenteral nutrition (TPN) is not free of complications. One of the most serious is cholestasis; the cause of this complication is unclear but it may be due to a lack of an enteral stimulus for cholecystokinin (CCK) production. CCK is essential for contraction of the gallbladder and also stimulates intrahepatic bile flow. Its absence may contribute to cholestasis. After any hepatic aggression, the Kupffer cells respond and release proinflammatory cytokines, such as interleukin-1 (IL-1) and tumour necrosis factor alpha (TNF-alpha), which increase the hepatic damage. The objective of this experimental study has been to observe the effect that the exogenous administration of CCK could have on hepatic damage in experimental short bowel with and without TPN, determined using the serum levels of IL-1 and TNF-alpha.

MATERIAL AND METHODS

A resection of 80% of the small bowel was performed on 53 Wistar rats and a continuous infusion of saline or TPN was initiated. The rats were divided into the following groups: SHAM (N = 14): normal saline infusion and free access to food and water. TPN (N = 15): Standard TPN. SHAM-CCK (N = 14): same as the SHAM group but with a daily dose of CCK. TPN-CCK (N = 10): same as the TPN group but with a daily dose of CCK. At the end of the experiment, the animals were sacrificed and blood samples were obtained to determine the IL-1 and TNF-alpha values by ELISA.

RESULTS

The IL-1 and TNF-alpha levels were higher in the TPN group (7.537 and 5.899 pg/mL, respectively) than in the SHAM group (6.509 and 4.989 pg/mL, respectively) (p > 0.05). The TNF-alpha values were higher in the SHAM group (4.989 pg/mL) than in the SHAM-CCK group (4.583 pg/mL) (p < 0.001). The IL-1 and TNF-alpha levels were higher in the TPN group than in the TPN-CCK group (6.709 and 4.794 pg/mL, respectively) (p < 0.001 for TNF-alpha).

CONCLUSIONS

1. There is a rise in the serum levels of the pro-inflammatory cytokines IL-1 and TNF-alpha in animals with short bowel on TPN or enteral nutrition. 2. The administration of CCK causes a fall in the IL-1 and TNF-alpha levels, and could be used such as a further measure to prevent TPN-associated cholestasis.

[Necrotizing enterocolitis and bacterial translocation: role of minimal enteral nutrition]

INTRODUCTION

Both necrotizing enterocolitis (NEC) and bacterial translocation (BT) have in common that bacterial overgrowth, a decrease in immunity and intestinal mucosal damage, followed by a barrier failure, can act as trigger factors. The main objectives in NEC treatment are to reduce mortality due to sepsis and to promote feeding tolerance. To achieve that, Minimal Enteral Nutrition (MEN) (less than 25% of the calories provided by enteral route) is a more and more used technique in newborns who receive Parenteral Nutrition (PN) to slow down fasting related villi atrophy and to attenuate its consequences.

AIM

To test the hypothesis that MEN decreases BT in an experimental model of PN.

METHODS

Twenty-four adult Wistar male rats received a continuous infusion of all-in-one PN solution through a jugular vein catheter. The animals were randomly divided in two groups and maintained in individual metabolic cages for ten days. * Control group (N= 1): fasting rats receiving, standard PN (300 mL/kg/ 24 h, 280 kcall kg/24 h). * MEN group (N=13): standard PN and rat chow (15 g /24 h, 3,1 kcal/g). At the end of the experiment animals were sacrificed and mesenteric lymph nodes (MLN), and both peripheral and portal blood samples were recovered and cultured. Bacterial identification in blood was carried out by conventional methods and MLN culture was considered positive with a growth over 100 Colony Forming Units/g.

RESULTS

Weight curve was better in MEN group and BT was also significantly reduced. Translocation was found in 45% of control group and 8% of MEN group (p < 0,05). The relative risk (RR) was 5,9 (IC 95% 0,81-43,71) and the number needed to treat (NNT) was 3 (95% CI 2-20).

CONCLUSIONS

1. MEN reduces the incidence of BT in an experimental model of parenteral nutrition. 2. BT reduction could decrease NEC-related sepsis risk.

[Selective intestinal decontamination and parenteral nutrition related liver disease. Experimental study]

Selective intestinal decontamination (SID) has been useful restraining Bacterial translocation (BT) in both animal models and human clinics. The not well known parenteral nutrition-related liver disease is a serious problem associated to short bowel and long-term parenteral nutrition (PN) use, and BT is also frequent in those patients. Germs reach liver through portal vein and activate Kupffer cells, which release cytokines as IL-1 or TNF-alpha. The aim of this study was to test the use of SID restraining BT in a PN undergoing experimental short bowel model, and its possible favourable consequences on hepatic injury determined by IL-1 and TNF-alpha levels. Twenty-five 240-280 g Wistar rats were divided into two groups and maintained in individual metabolic cages for ten days: Resection-PN group (n=15): animals with a bowel resection of the 80% and a continuous PN infusion. Resection-PN-SID (n=10) group: similar to previous group and a daily oral administration of Tobramycine (20mg/kg/day) and Polymyxine-E (25mg/kg/day). Animals were sacrificed and mesenteric lymph nodes (MLN), and both peripheral and portal blood samples were recovered for TB determination in bacterial culture. Determination of both IL-l and TNF-alpha seric levels were carried out by ELISA. Bacterial translocation incidence was higher in RES-NPT group (66.6%) than RES-NPT-SID group (30%) (P>0,05). The relative risk was 2.22 (IC 95% 0,81-6,11) and the number needed to treat was 3 (IC 95% 2-235). Seric levels of IL-1 and TNF-alpha were also higher in RES-NPT group (7,537 and 5,399 pg/ml, respectively) than in RES-NPT-SID group (6,397 and 5,032 pg/ml respectively) (p<0,001). 1. SID reduces TB in a PN undergoing experimental short bowel resection murine model. 2. Parenteral nutrition-related liver disease decreases in DIS receiving animals.

[Severe primary vesicoureteral reflux in infants. A follow-up of 203 cases]

OBJECTIVE

The aim of our study is to analyze the clinic characteristics and evolution of the primary reflux in infants.

METHODS

We studied retrospectively 203 infants in our hospital, diagnosed of severe primary renal reflux. Renal ecography and cyclic mictional cystography were practiced in all cases. DMSA was carried out in 181 patients.

RESULTS

Renal reflux was unilateral in the 23% of the patients, and bilateral in the remaining cases; 72% of the renal reflux were grade IV and 28% grade V. The renal injuries affected to male infants and reflux grade V. The renal injury was focal (27%), global (44%) and atrophic (29%). The 79% of the patients had conservative treatment, while 21% had surgical treatment. 100% infants with surgical treatment and 94.2% infants with conservative treatment were recovered (Test of Kaplan-Meier). The 27% of patients developed one or several urinary infections, but progression of old renal injuries or formation of new ones, were exceptional (3 cases): While the time the study lasted none of the patients developed chronic renal failure nor arterial hypertension.

CONCLUSIONS

1) The fetal severe primary reflux of the patients was characterized by the following features: to be bilateral reflux, to affect mainly to male infants and to be associated in 33% of cases with a severe renal injury of congenital origin (renal displasia) most of them unilateral. 2) The natural evolution of the reflux goes to spontaneous recovery, so treatment must be conservative. 3) Some patients underwent urinary infections, but progression or formation of new renal injuries were inusual. None of the patients had terminal renal failure nor hypertension and 4) Risk patients would be male infants with bilateral injuries although these are infrequent.

[Incidence of bacterial translocation in four different models of experimental short bowel syndrome]

The outcome of patients with short bowel syndrome is influenced for factors such as the length of remnant intestine or the presence or absence of ileocecal valve (ICV). Gram-negative sepsis, the main cause of mortality in this group of children, is probably due to bacterial translocation (BT), because after gut resection there are a number of circumstances that favour its occurrence, being the most known intestinal dismotility, bacterial overgrowth, loss of gut-associated lymphoid tissue, total parenteral nutrition (TPN) and fasting related mucosal atrophy. The aim of this experimental controlled study was to test the incidence of BT after four different types of gut resection, in animals fed orally or receiving TPN. Hundred and three adult Wistar rats bred and raised in our facilities according to European Union Regulations were randomly divided in six groups:--Group 1 (n = 26): non-manipulated animals, served as a control.--Group 2 (n = 14): 80% non-lethal small bowel resection, fed orally.--Group 3 (n = 15): same resection as group 2 but including ICV. Rat chow ad libitum.--Group 4 (n = 27): non-resected fasting animals receiving all-in-one TPN solution.--Group 5 (n = 11): same resection as group 2, but fasting and receiving TPN--Group 6 (n = 10): 90% small bowel resection, including cecum and ICV, fasting and TPN. The animals were maintained for 10 days in individual metabolic cages, and, at the end of the experiment, were bled by portal and cardiac puncture. Mesenteric lymph nodes, peripheral and portal blood samples were cultured for BT. Non-manipulated rats (group 1) had lower BT incidence (8%) than resected ones (groups 2, 3, 5 and 6, 93%, 60%, 91%, 60%, p < 0.05) or animals non-resected, receiving TPN (group 4.51%, p < 0.05). When resection included ICV in orally fed rats BT index was also lower (group 3 vs group 2.60% vs 91%, p < 0.05). In TPN resected animals a drop was also found in BT when ICV and cecum were added to small bowel resection (group 6 vs group 5.60% vs 91%, p < 0.05).

IN CONCLUSION

1. Gut resection is associated to a high degree of BT, even if the animals are fed orally. 2. Resection including ICV, produced less BT. 3. TPN-related BT was shown in half of the animals non resected. 4. TPN-resected rats had also less BT when ICV and cecum were removed.

[Beneficial effects of Bifidobacterium lactis in the prevention of bacterial translocation in experimental short bowel syndrome]

BACKGROUND

Probiotics are live organisms that survive passage through the gastrointestinal tract and have beneficial effects on the host. Lactobacillus and Bifidobacterium have been recommended in cholesterol lowering, acute diarrhea, prevention of cancer or inflammatory bowel disease. On the other hand, after massive bowel resection bacterial overgrowth is frequent and favours the occurrence of bacterial translocation (BT). The possible beneficial effects of Bifidobacterium lactis (BL) administration on BT in experimental short bowel syndrome (SBS), have not been investigated.

AIM

To test the hypothesis that BL administration decreases BT in SBS in animals fed orally.

METHODS

Thirty-two adult Wistar rats fed orally with standard rat chow and tap water "ad libitum" were maintained individual metabolic cages for ten days after 80% gut resection from the duodeno-jejunal angle to 10 cm above the cecum and divided in two groups: -Group A (n = 14): served as control. -Group B (n = 18): daily 7.8 x 109 CFU Bifidobacterium lactis administration, after orgastric intubation. At the end of the experiment they were sacrificed and mesenteric lymph nodes (MLN), and peripheral and portal blood specimens were recovered and cultured. Bacterial identification in blood was made by conventional methods and MLN culture was considered positive with a growth over 100 CFU/g.

RESULTS

Bacterial translocation was detected in 93% of Group A rats. The incidence of BT in Group B was 44%. The relative risk reduction (RRR) was 0.52 (95% confidence interval 0.23-0.81) and the number needed to treat (NNT) was 2 (95% confidence interval between 1-5).

CONCLUSION

Administration of Bifidobacterium lactis reduces the incidence of BT in adult Wister rats, after 80% gut resection.

Probiotic supplementation reduces the risk of bacterial translocation in experimental short bowel syndrome

BACKGROUND/PURPOSE

Probiotics are live organisms that survive passage through the gastrointestinal tract and have beneficial effects on the host. Lactobacillus and Bifidobacterium have been recommended for cholesterol lowering, acute diarrhea, prevention of cancer, or inflammatory bowel disease. On the other hand, after massive bowel resection, bacterial overgrowth is frequent and favors bacterial translocation (BT). The possible beneficial effects of Bifidobacterium lactis (BL) administration on BT in experimental short bowel syndrome (SBS), have not been investigated. The aim of this study was to test the hypothesis that BL administration decreases BT in SBS in animals fed orally.

METHODS

One hundred twenty-eight adult Wistar rats fed orally with standard rat chow and tap water "ad libitum" were maintained in individual metabolic cages for 10 days and divided into 3 groups: control group (n = 71): nonmanipulated animals; RES group (n = 39): 80% gut resection from 10 cm beyond the angle of Treitz to 10 cm above the cecum; RES-PRO group (n = 18): same resection and daily 7.8 x 10(8) CFU B Lactis administration, after orogastric intubation. At the end of the experiment they were killed, and mesenteric lymph nodes (MLN) and peripheral and portal blood specimens were recovered and cultured. Bacterial identification in blood was made by conventional methods, and MLN culture was considered positive with a growth over 100 CFU/g.

RESULTS

Bacterial translocation was detected in 6% of control group rats. The incidence of BT in the RES group was 87% (34 of 39), whereas only 50% (9 of 18) of RES-PRO animals had BT (P <.05). The relative risk reduction (RRR) was 0.43 (95% Cl 0.14 to 0.72), and the number needed to treat (NNT) was 3 (95% Cl 2 to 8). In other words, animals that received BL had the risk of BT reduced by 43% (RRR of 0.43), and of every 3 animals treated, 1 is expected to be free of BT (NNT of 3).

CONCLUSION

Administration of B Lactis reduces the incidence of BT in adult Wistar rats after 80% gut resection.

[Tissue antioxidant capacity and bacterial translocation in parenteral nutrition. Experimental study]

Alterations in the antioxidant system (AS) has been observed during total parenteral nutrition (TPN). Light exposure or changes in the composition of TPN may affect this deleterious effect. On the other hand, bacterial translocation (BT) is frequent under TPN and may be related to AS. The aim of the study was to determine the adverse effect of standard and glutamine-enriched (GE) TPN, with or without light exposure, on the AS, and its relationship to BT. Forty-nine adult Wistar rats underwent central venous cannulation and were randomly assigned to one of five groups: Sham (n = 16): chow and water ad libitum and saline i.v. TPN (n = 10): had standard TPN. TPN(-) (n = 8): standard TPN without light-exposure. GTPN (n = 8): GE TPN. GTPN(-) (n = 7): GE TPN without light exposure. After 10 days, glutation reduced (GSH) was determined in liver and kidney. Mesenteric lymph nodes, peripheral and portal blood samples were cultured for BT. Comparing to Sham rats, TPN groups had statistically significant lower GSH levels, but there were no differences between standard or GE groups nor with or without light exposure groups. Sham animals had 12% BT. Significantly higher BT (p < 0.05) was found in TPN rats: 70% in TPN group, 88% in TPN(-) group, 86% in GTPN(-) animals and only 50% in GTPN group (p = 0.06 vs TPN group). To conclude: 1. TPN reduces antioxidant capacity and induces BT. 2. Glutamine supplementation or light protection do not improve tissue antioxidant capacity under TPN. 3. Glutamine supplementation tends to reduce BT only in the presence of light. 4. Absence of light exposure does not improve BT TPN-related.

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.

[Bacterial translocation associated with short bowel: role of ileocecal valve and cecum]

Sepsis in short bowel syndrome (SBS) is due in part to bacterial translocation (BT). Parenteral nutrition (PN) is often necessary in SBS and promotes BT. The presence of ileocecal valve (ICV) has been considered as a good prognostic factor in the outcome of this children. The aim of this study was to asses the effect of the presence or absence of ICV and cecum in five different models of gut resection in the rat. Fifty-five adult Wistar rats were randomly assigned to one of five groups: Group 1 (N = 14): standard rat chow + 80% small bowel resection. Group 2 (N = 10): standard rat chow + 80% small bowel resection including cecum. Group 3 (N = 10): standard rat chow + 80% small bowel resection including ICV. Group 4 (N = 11): NP + 80% small bowel resection. Group 5 (N = 10): NP + 80% small bowel resection including ICV and cecum. Ten days after surgery they were sacrificed and mesenteric lymph nodes (MLN), spleen and peripheral (PBL) and portal blood (POBL) specimens were recovered and cultured. Groups 3 (without ICV, with cecum) and 5 (without ICV, without cecum) showed 60% BT in MLN and POBL, and groups 1 and 4 (with ICV, without cecum) 93% and 91% respectively (p < 0.05). In PBL, group 3 (without ICV, with cecum) showed also less BT than groups 1 and 4 (10% vs 43% and 55% respectively, p < 0.05) and group 5 (without ICV and cecum) had less BT than groups 1, 2 and 4 (0% vs 43%, 30% and 55%, p < 0.01). In conclusion, these results suggest that the absence of ICV decreases BT and that the cecum does not seems to play a role on his.

[Effect of various trophic factors on bacterial translocation in experimental short bowel syndrome]

Massive bowel resection triggers an adaptive process in the remaining intestine in spite of which, bacterial translocation (BT) is frequent under these conditions. Several trophic factors, including growth hormone (GH), epidermal growth factor (EGF) and insuline (INS) are involved in the process of adaptation in short bowel syndrome (SBS). However, the effect of GH, EGF or INS on BT has not been investigated experimentally. The aim of the study was to test the hypothesis that GH, EGF or INS administration prevents BT in rats with SBS receiving only parenteral nutrition (PN). Thirty-seven adult Wistar rats underwent central venous cannulation and were randomly assigned to one of two groups receiving for ten days four treatment regimes: PN group (N = 10) fasting, all-in-one PN solution (300 mL/kg/24 h, 280 kcal/kg/24 h), 80% gut resection including ileo-cecal valve. GH group (N = 9) fasting, same PN regime and resection plus GH (1 mg/kg/d, s.c.). EGF group (N = 9): same PN regime and resection plus EGF (150 microgr/24 h, e.v.) INS group(N = 9): same PN regime and resection plus INS (1 U.I./100 g/24 h s.c.) At the end of the experiment the rats were exanguinated and mesenteric lymph nodes and samples of systemic and portal blood were obtained and cultured. Several samples of full-thickness jejunal wall were taken for measuring cell proliferation index (PCNA) and mucosal thickness. Jejunal mucosal thickness increased by 30%, 28% and 29% and PCNA index by 21%, 20% and 25% in GH, EGF and INS, treated rats respectively in comparison with those treated with PN alone. However, contrary to our expectations, BT expressed by positive culture of intestinal germs in systemic blood was demonstrated respectively in 44%, 40% and 28% of GH, EGF and INS animals, respectively, and in 0% of PN-only rats. Although exogenous GH, EGF or INS improves gut mucosal structure in rats with SBS treated with PN, it seems to increase rather than decrease mucosal permeability to intestinal germs in them.

Effect of growth hormone, epidermal growth factor, and insulin on bacterial translocation in experimental short bowel syndrome

BACKGROUND/PURPOSE

An adaptive process starts in the remaining intestine after massive resection, and several trophic factors including growth hormone (GH), epidermal growth factor (EGF), and insulin (INS) have been shown to have a positive effect on it. Bacterial translocation (BT) is frequent after extensive small bowel resection, but the effects of GH, EGF, or INS have not been investigated in experimental short bowel syndrome (SBS). This study tests the hypothesis that GH, EGF, or INS decrease BT in SBS in rats with parenteral nutrition (PN).

METHODS

Thirty-eight adult Wistar rats underwent central venous cannulation and were assigned randomly to 1 of 4 groups receiving for 10 days 4 treatment regimes: (1) PN group (n = 10): fasting, all-in-one PN solution (300 mL/kg/24 h, 280 kcal/kg/24 h), 80% gut resection including ileo-cecal valve; (2) GH group (n = 9): fasting, same PN regime and resection, GH (1 mg/kg/d, subcutaneously); (3) EGF group (n = 9): fasting, PN, resection, EGF (150 microg/24 h intravenously); (4) INS group (n = 9): fasting, PN, resection, INS (1 UI/100 g/24 h subcutaneously). At the end of the experiment they were killed, and mesenteric lymph nodes (MLN) and peripheral and portal blood samples were recovered and cultured. Several fragments of intestine were taken to determine cell proliferation (PCNA index) and morphometric parameters (villous height, crypt depth).

RESULTS

GH, EGF, and INS groups showed a 28%, 29%, and 30% increase in gut mucosal thickness, and PCNA index rose 21%, 20%, and 25%, respectively in comparison with PN controls. Bacterial translocation to peripheral blood was detected in 0% of PN animals and in 44%, 40%, and 28% of GH, EGF, or INS rats, respectively (P < .05). No differences were found in BT in MLN or portal blood among groups.

CONCLUSION

Administration of GH, EGF, or INS improves gut mucosal structure in rats with SBS under PN, but, surprisingly, the incidence of BT detected in peripheral blood was increased rather than decreased in animals receiving these treatments.

Bacterial translocation is favored by the preservation of the ileocecal valve in experimental short bowel with total parenteral nutrition

Sepsis in short-bowel syndrome (SBS) is in part due to bacterial translocation (BT). Parenteral nutrition (PN) is often necessary in SBS and promotes BT. The aim of this study was to asses the effect of the presence or absence of ileocecal valve (ICV) on BT in parenterally-fed rats with massive intestinal resection. Sixty-five adult Wistar rats underwent central venous cannulations and were randomly assigned to one of five groups receiving for ten days five treatment regimes: Sham (n = 17) standard rat chow + i.v. saline. PN (n = 17) fasting + PN. Res-Sham (n = 10) standard rat chow + i.v. saline + 80% gut resection. Res-PN (n = 11) fasting, PN + 80% gut resection. Res-ICV-PN (n = 10) fasting, PN + 80% gut resection including ICV. At the end of the experiment they were euthanized and mesenteric lymph nodes (MLN), spleen and peripheral and portal blood specimens were recovered and cultured. BT was found in 47% of PN animals, 91% of Res-PN rats, 100% of Res-Sham group and 60% of Res-ICV-PN animals, but not in Sham ones. 97% of BT+ animals had positive cultures in MLN and/or portal blood, whereas germs beyond liver were detected in 30% of Res-Sham, 37% of PN, 50% of Res-PN and 0% of Res-ICV-PN rats. The present study confirms that both massive intestinal resection and PN promote BT. In addition, it shows that animals deprived of ICV have lower incidence of BT in this setting than those with it and that the germs do not reach in them peripheral blood in the same proportions as in ICV-intact animals. These results suggest that the presence of an intact ICV favor BT in parenterally-fed rats with massive intestinal resection.

Effect of growth hormone on bacterial translocation in experimental short-bowel syndrome

Despite the adaptive process triggered in the remaining intestine by massive bowel resection, bacterial translocation (BT) is frequent under these conditions. Several trophic factors, including growth hormone (GH), are involved in the process of adaptation in short-bowel syndrome (SBS). However, the effect of GH on BT has not been investigated experimentally. The aim of this study was to test the hypothesis that GH administration prevents BT in rats with SBS receiving only parental nutrition (PN). Nineteen adult Wistar rats underwent central venous cannulation and were randomly assigned to one of two groups receiving for 10 days two treatment regimes: PN group (n = 10): fasting, all-in-one PN solution (300 ml. kg. 24 h, 280 kcal/kg. 24 h), 80% gut section including ileocecal valve; GH group (n = 9): fasting, same PN regime and resection plus GH 1 mg/kg s.c). At the end of the experiment, the rats were killed and mesenteric lymph nodes (MLN) and samples of systemic and portal blood were obtained and cultured. Several samples of full-thickness jejunal wall were taken for determining cell proliferation index (PCNA) and mucosal thickness. Jejunal mucosal thickness increased by 30% and PCNA index by 35% in GH-treated rats in comparison with those treated with PN alone. However, contrary to our expectations, BT expressed by positive culture of intestinal flora in portal blood, MLN, or systemic blood was found in 60% of PN and 87% of GH animals (P = 0.1). Translocation to the general circulation expressed by the presence of organisms in systemic blood was detected in 0% of PN and 44% of GH rats (P < 0.05). Although exogenous GH improves gut mucosal structure in rats with SBS treated with PN, it seems to increase rather than decrease mucosal permeability to intestinal bacteria.

Bacterial translocation and T-lymphocyte populations in experimental short-bowel syndrome

Bacterial translocation (BT) accounts in part for sepsis in short-bowel syndrome in which total parenteral nutrition (TPN) is routinely necessary. TPN "per se" facilitates BT and it has been suggested that decreased T-lymphocyte populations (TLP) in newborn rabbits and nude mice promote BT as well. We have tested the hypothesis that BT and modifications in TLP are to be expected in rats subjected to TPN and gut resection. Forty-five adult Wistar rats underwent central venous cannulations and were randomly assigned to one of three groups receiving for ten days three treatment regimes: - Group Sham (n = 17) oral intake of rat chow + saline (300 ml/kg/24 h) through a jugular vein catheter. - Group TPN (n = 17) fasting + infusion of all-in-one TPN solution (300 ml/kg/24 h). - Group RES (n = 11) fasting, same TPN regime + 80% gut resection. At the end of the experiment they were sacrified and specimens (peripheral and portal blood, spleen and mesenteric lymph nodes) were recovered, cultured and/or assessed for CD4+ and CD8+. Bacterial translocation was found in 47% of TPN animals, 92% of RES rats, but not in SHAM ones. Lymphocyte populations were not different in BT+ (n = 8) or BT- (n = 9) rats in the TPN group. TPN and resected animals showed a rise in CD4+ and a drop in CD8+ (then a better CD4+/CD8 ratio) when comparing with SHAM group rats. From this data we may conclude that: 1) BT is frequent if TPN is administered, and constant in resected animals. 2) No apparent relationship between the proportions of CD4+ and CD8+ lymphocytes and BT could be shown in TPN group. 3) High CD4+/CD8+ ratio in TPN and RES groups demonstrate that BT is possible even having good TLP.

[Saliva in experimental gastroesophageal reflux]

Saliva, with a neutral pH, mucous content and inhibitory factors of the stomach acid secretion, can be considered a protecting element of the esophageal mucosa in the gastroesophageal reflux. 39 Wistar rats 175-225 g were used divided in seven groups: "C" control, "E-A" esophago-gastrostomy. "E-M" esophago-myectomy, "S-C" only sialoadenectomy, "S-EA" sialoadenectomy plus esophagogastrostomy, "S-EM" sialoadenectomy plus esophago-myectomy. 15 days later the rats were sacrificed, the esophagus was taken out for its histological examination and blood samples were drawn. The comparison between the control and treated groups, showed a significant deterioration of the EA, SEA and SEM groups regarding the final weight, and the SC group in the white series and ions. Many of the animals with esophagus operations showed vomit signs and general affectation. None of the groups showed esophageal lesions in the histology, from which it can be deduced that, in the rat, a 90% saliva absence doesn't produce negative effects on the esophageal mucosa either in acid presence or not.

[Gastroesophageal reflux and ventilation with continuous positive pressure. Experimental study]

Gastroesophageal reflux (GER) often occurs in babies receiving respiratory assistance for neonatal distress. The authors examined the lower esophageal sphincter and the thoracic and abdominal pressure conditions in rats under progressively higher continuous positive airway pressure (CPAP) to test the efficacy of the antireflux barrier under such conditions. Intrathoracic and intraabdominal pressures were recorded within the esophagus and within the inferior vena cava in 10 anesthesized 250-g male rats. Pull-through techniques were used for lower esophageal sphincter pressure (LESP) and length (LESL) studies, and the length of the intraabdominal segment of the esophagus (LIASE) was also determined. Measurements were performed in baseline conditions and at CPAP levels of 0, 1, 3, 5 and 7 cm H2O. The respiratory effort progressively increased with prolonged expiration and decreased frequency. LESP and LESL did not change significantly, but the antireflux barrier was weakened by a progressive shortening of LIASE. Successive CPAP increases led to increasingly negative thoracic pressures during inspiration, and increasingly positive abdominal pressure during expiration yielded progressively greater transdiaphragmatic pressure gradients. The authors suggest that CPAP weakens the antireflux barrier and, at the same time, increases the gastroesophageal pressure gradient, thus increasing the risk of GER. Although transpolation of experimental data to the clinical setting is always hazardous, the authors believe this issue should be investigates in infants.

Lymphocyte subpopulations after extensive small bowel resection in the rat

The increased risk of infection after massive intestinal resection (MIR) may be attributable to impaired nutrition, loss of intestinal lymphoid tissue, or both. This study examines whether MIR itself changes the immune cell populations in laboratory animals when nutritional status is preserved. The authors studied cellular immunity (lymphocyte subsets T4 and T8 and the T4:T8 ratio) and humoral immunity (IgG, IgM, IgA, and B lymphocytes) in the blood, spleen, and mesenteric lymph nodes of unresected Wistar rats (control group, n = 6) and of animals that underwent 80% bowel resection followed by 7 days of either oral feeding (resection-oral group, n = 6) or parenteral nutrition (resection-TPN group, n = 6). The increase in body weight was similar among all groups, and the levels of total protein, albumin, prealbumin, and immunoglobulin remained unchanged. All resected animals, irrespective of their feeding route, had significantly lower proportions of T4 and B lymphocytes and T4:T8 ratio in blood, T4 and T8 in mesenteric lymph nodes, and T4 and T4:T8 ratio in the spleen. The author's results suggest that removal of large amounts of lymphoid tissue along with the bowel during MIR might lead to inadequate immune response even when the nutritional status is preserved.

Characteristics of continuous esophageal pH-metering in infants with gastroesophageal reflux and apparent life-threatening events

Episodes of apnea during the first year of life have been classified with the term "Apparent Life-Threatening Events" (ALTE). Gastroesophageal reflux (GER) has been accepted to be one of the factors which can favor ALTE. The aim of this work is to study the continuous 24 h gastroesophageal pH-metering (fundamentally the Reflux Index [RI] and the Area Under Curve [AUC] parameters in three different periods of time: total pH-metering, pH-metering excluding the first two post-prandial hours, and pH-metering during sleep time, for 24 infants, 14 with ALTE and 10 without it). Between these two groups (with and without ALTE) there were no significant differences in the total pH-metering concerning the RI (2 +/- 1.2 vs 5.6 +/- 7.5 p > 0.05) and concerning the AUC (24.9 +/- 14.4 vs 67.4 +/- 84 p > 0.05), but in the analysis of the sleep period, the RI (p < 0.05) and the AUC (p < 0.01) both showed significant differences in the group of infants without ALTE. These results confirm that pH-metering study during sleep is the procedure of choice for recognizing infants with ALTE.

Continuous positive airway pressure and gastroesophageal reflux: an experimental study

Gastroesophageal reflux (GER) often occurs in babies receiving respiratory assistance for neonatal distress. The authors examined the lower esophageal sphincter and the thoracic and abdominal pressure conditions in rats under progressively higher continuous positive airway pressure (CPAP) to test the efficacy of the antireflux barrier under such conditions. Intrathoracic and intraabdominal pressures were recorded within the esophagus and within the inferior vena cava in 10 anaesthesized 250-g male rats. Pull-through techniques were used for lower esophageal sphincter pressure (LESP) and length (LESL) studies, and the length of the intraabdominal segment of the esophagus (LIASE) was also determined. Measurements were performed in baseline conditions and at CPAP levels of 0, 1, 3, 5, and 7 cm H2O. The respiratory effort progressively increased with prolonged expiration and decreased frequency. LESP and LESL did not change significantly, but the antireflux barrier was weakened by a progressive shortening of LIASE. Successive CPAP increases led to increasingly negative thoracic pressures during inspiration, and increasingly positive abdominal pressures during expiration yielded progressively greater transdiaphragmatic pressure gradients. The authors suggest that CPAP weakens the antireflux barrier and, at the same time, increases the gastroesophageal pressure gradient, thus increasing the risk of GER. Although transpolation of experimental data to the clinical setting is always hazardous, the authors believe this issue should be investigated in infants.

Simultaneous gastroesophageal pH monitoring and the diagnosis of alkaline reflux

The diagnosis of alkaline gastroesophageal reflux (AGER) by esophageal pH-monitoring is elusive because several other causes may raise esophageal pH above 7. This study approaches the issue by simultaneously recording esophageal and gastric pH with a 2.1 mm assembly of two antimony electrodes in refluxing (n = 69) and nonrefluxing (n = 40) children. On the basis of the information gathered, patients were divided into four groups: acid refluxers (GER, n = 40 or 57%), alkaline refluxers (AGER, n = 8 or 11%), alkalacid refluxers (AAGER, n = 15 or 22%), and silent refluxers or false negatives (SGER, n = 6 or 9%). Children with AGER could not be differentiated from other refluxers nor from controls by esophageal pH information alone. Prolonged gastric buffering or alkalinization could be documented in both AGER and AAGER children, indicating extended duodenogastric reflux (DGR) in them. The incidence of esophagitis was not significantly different between the groups of refluxers: 75% for AGER and AAGER, 73% for GER, and 67% for SGER. AGER, a disorder involving both pyloric and gastroesophageal barriers, is as significant a problem in children as in adults and may lead to severe complications even in the absence of excessive acid exposure. Monitoring esophageal pH alone is insufficient for making the diagnosis of AGER. The diagnosis can be made with little more expense and similar patient discomfort using the two-probe test. We suggest the need for a critical reassessment of the current antacid and prokinetic GER treatments and of antireflux operations which leave DGR intact while correcting GER.

[The defense against infection in the short bowel syndrome]

The high risk of infection in the short-bowel syndrome (SBS) may be due to malnutrition, lost of lymphoid bowel structures or both. Total parenteral nutrition (TPN) may alleviate the malnutrition, but we do not know what will happen with immune response in SBS with good nutritional state. We have studied the cellular immunity (lymphocytic subsets T4 and T8 and T4/T8 ratio) and the humoral one (IgG, IgM, IgA and B lymphocytes) in blood, spleen and mesenteric lymph nodes, in 12 wistar rats with 80% bowel resection, 6 of them with oral feeding and 6 with TPN, and 6 control rats, during 7 days. The weight increased and the total protein, albumin and prealbumin levels were the same in all groups. There was not difference between the resected groups. No difference was observed in the rate of immunoglobulins and the resected groups showed significatively lower figures than the control group in T4, B lymphocytes and T4/T8 ratio in blood, T4 and T8 in mesenteric nodes and in T4 and T4/T8 ratio in the spleen. These results suggest that the resection of large amounts of bowel could produce a fall in the immune response even when adequate nutritional state is preserved.

Airway obstruction and gastroesophageal reflux: an experimental study on the pathogenesis of this association

Gastroesophageal reflux (GER) frequently complicates the clinical course of children suffering from conditions leading to upper airway obstruction (UAO) (choanal atresia, tracheomalacia, esophageal atresia, vascular rings, etc). In an attempt to explore whether partial airway obstruction causes changes in the normal thoracoabdominal pressure gradients, we measured end-inspiratory intrathoracic and intraabdominal pressures in anesthetized rats under spontaneous breathing conditions, after tracheostomy, and under upper airway obstruction induced by tracheal intubation with three progressively narrower cannulae (inner diameters 1.0 mm, 0.5 mm, and 0.2 mm). We also measured the lower esophageal sphincter pressure (LESP) and length (LESL) and calculated the thoracoabdominal end-inspiratory pressure gradient (TAEIPG). Neither LESP nor LESL changed significantly before or after maximal tracheal obstruction (14.3 +/- 6.2 v 18 +/- 7.6 cm H2O [P > .05] and 0.34 +/- 0.09 v 0.41 +/- 0.1 cm H2O [P > .05] respectively) but TAEIPG significantly increased from 5.58 +/- 1.34 cm H2O to 17.62 +/- 4.27 cm H2O (P < .01) under the same conditions, mainly as a result of progressively increasing negative intrathoracic pressures during inspiration. These experiments prove that the powerful thoracoabdominal pressure gradients developed after partial UAO may contribute to the pathogenesis of GER by overcoming the antireflux barrier function. This study points out the convenience of routinely screening for GER all children with airway obstructive conditions, bearing in mind that the reestablishment of normal respiratory conditions should be the primary goal of treatment.

[Duodenogastric reflux: values in normal children and in children with gastroesophageal reflux]

Duodenogastric reflux (DGR) is a natural event, occurring occasionally and whose pathological significance is not well known. The accuracy of 24-hour gastric pH-metry for the DGR diagnosis has been tested in adults but not in children. For this purpose we measured the area under curve (AUC) at pH 4, 6 and 7 and the percentage of total time above pH 4 (%pH4), 6 (%pH6) and 7 (%pH7), excluding the 2-hours post-prandial period in 88 children suspected of having gastroesophageal reflux (GER). Forty were considered normal whereas 40 had acid GER and 8 with GER. In the control group %pH4 was 9.68 +/- 14.1, %pH6 3.4 +/- 8.7 and %pH7 1.0 +/- 2.4. The values for AUC were 101 +/- 112.8, 16.5 +/- 22.3 and 3.3 +/- 6.1 pH unit/min, respectively. Comparable results were found in the acid GER group. On the other hand alkaline refluxes had higher figures for all parameters: %pH4 22.1 +/- 13.9, %pH6 12 +/- 13 y %pH7 7 +/- 12, AUC at pH 4,406.5 +/- 410, 136.1 +/- 194 at pH6 and 48.2 +/- 85.1 at pH7 (p < 0.05). Because of the large dispersion of values in the control group we selected the 95 percentile, as the upper limit of normal values instead of the mean +/- SD. Therefore the upper limit were 27 for %pH4, 9 for %pH6 and 3.8 for %pH7. The AUC, 316, 64 and 16 pH/min, respectively. These results prove that DGR in children is a very common event and confirm that DGR definitely contributes to alkaline GER.

[Airway obstruction associated with gastroesophageal reflux: experimental study]

Gastro-oesophageal reflux (GER) frequently complicates the clinical course of children suffering from conditions leading to upper airway obstruction (UAO) (choanal atresia, tracheomalacia, oesophageal atresia, vascular rings etc.). In an attempt to explore whether partial airway obstruction causes changes in the normal thoraco-abdominal pressure gradients, we measured end-inspiratory intrathoracic and intra-abdominal pressures in anesthesized rats under spontaneous breathing conditions, after tracheostomy and under upper airway obstruction induced by tracheal intubation with three progressively narrower cannulae (inner diameters 1.0 mm, 0.5 mm. and 0.2 mm.). We also measured the lower oesophageal sphincter pressure (LESP) and length (LESL) and calculated the thoraco-abdominal end-inspiratory pressure gradient (TAEIPG). Neither LESP nor LESL changed significantly before or after maximal tracheal obstruction but TAEIPG significantly increased from 5.58 +/- 1.34 cm H2O to 17.62 +/- 4.27 cm. H2O (p < 0.01) under the same conditions, mainly as a result of progressively stronger intra-thoracic pressures during inspiration. These experiments prove that the powerful thoraco-abdominal pressure gradients developed after partial UAO may contribute to the pathogenesis of GER by overcoming the anti-reflux barrier function.

[Barrett++ esophagus in children. Presentation of 12 cases]

This paper describes 12 cases of Barrett's oesophagus selected out of a population of 364 refluxing children studied from 1986 to 1990. Their mean age was 14, seven were cared for in special institutions for brain damaged and 2 had been operated upon for oesophageal atresia at birth. Excessive acid exposure was documented in 8/10 patient studied and simultaneous gastric and oesophageal pH-monitoring demonstrated massive duodeno-gastric alkaline reflux in 3. Histological studies revealed that columnar-lined epithelium was of fundic type in 2 cases, of junctional type in 7 and of specialized type in three. Helicobacter pylori was found in the mucosa of 8 patients. The present series confirms that BE should be looked for endoscopically in children with GER and provides further evidence of the long duration of GER disease and the excessive acid-alkaline chemical exposure of the oesophageal lining in the pathogenesis of mucosal changes.

[Alkaline gastroesophageal reflux. Diagnosis by double-channel pH measurement]

Alkaline gastroesophageal reflux (AGER) has been documented in adult subjects, but few in pediatrics. 24-hours double pH-monitoring was performed in 40 nonrefluxers (control group) and 69 gastroesophageal reflux (RGE) children to quantify AGER. Esophageal phmetric variables were measured at 4 and 7 levels; gastric variables were measured at 4. Forty cases were classified into acid GER, 15 into acid alkaline GER (mixed), 8 into AGER, and 6, with clinical, manometric or endoscopic evidence of GER into "silent" GER. The acid and mixed GER groups had longer periods of acid exposure in esophagus than control, AGER and "silent" GER groups. All groups had long periods of pH > 7 in esophagus. In conclusion, the double gastroesophageal pH monitoring, by verifying the source of alkaline reflux into the esophagus had advantage of better quantifying alkaline reflux over single pH monitoring. AGER might be more frequent in pediatrics than adults.

[Total parenteral nutrition in rats]

Total parenteral nutrition (TPN) is difficult in rats because of their activity and aggressivity. On the other hand, this animal is an ideal experimental subject because it is easy to handle, resistant to infections, it has a short vital cycle and is very cheap. Long-term TPN can be simulated in rats after only relatively short periods of infusion. We report herein the results on TPN in rats obtained in our laboratory. Male Wistar rats (n = 86) weighing 170-225 g had a central line inserted under general anesthesia and received 330 mL/kg/day of fluids. They were divided into an Experimental Group (n = 70) that had a solution containing carbohydrates, proteins and lipids (310 Kcal/kg/day) and a Control Group (n = 16) receiving only saline and having free access to rat pellets. Total infusion time was 582.9 days. Twenty-five percent of the rats were withdrawn because of technical problems, 7% because of infection, 46% died and only 22% survived until the end of the experimental period. All animals gained weight. Those in the Experimental Group had significantly higher total protein and Chloride whereas those in the Control Group had higher leukocytes, BUN, liver weight, large bowel length and spleen relative weight. This TPN rat model is suitable for metabolic studies in the laboratory and should be further developed.

Predicting preoperatively the outcome of respiratory symptoms of gastroesophageal reflux

The fact that bronchopulmonary symptoms remain unchanged in about 15% of patients after successful operation for gastroesophageal reflux (GER) with respiratory tract disease (RTD) makes surgical indications uncertain and warrants further research into preoperative prognostic predictors. This problem has been addressed in infants by demonstrating that those most likely to be cured by antireflux procedures have long nocturnal episodes of GER and/or temporal coincidence between drops in pH levels and respiratory episodes. In an attempt to validate these predictors and, at the same time, to search for other reliable ones, we have retrospectively studied the charts, manometric studies, pH tracings, and pathology reports of 55 patients aged 48 +/- 36 months (range, 2 to 170) who had Nissen funduplication for GER with RTD in the last 10 years. Forty-five children were cured or improved of their RTD symptoms after operation, but in 10 (18%) they were unchanged in spite of the control of GER. Patients with a former history of vomiting (n = 38) had better results than those (n = 17) without it (95% of RTD cure v 53%, P less than .001). The success rate in children with recurrent obstructive airway disease (n = 20) was definitely lower than in those without it (n = 35) (70% v 89%, P less than .05). Neither esophageal manometry nor mucosal biopsy provided any predictive clue, but pH studies confirmed that the mean duration of nocturnal episodes of reflux (ZMD) was definitely longer in patients responding favourably to surgical cure of GER than in those in whom this failed (12.2 +/- 9.6 v 3.9 +/- 2.8 minutes, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

[Warren's shunt in the treatment of portal hypertension in children]

Portal hypertension (PH) is often of extrahepatic origin in children. Several approaches have been proposed for its management: Observation, endosclerosis, devascularization and portosystemic shunting. Only the latter has an adequate haemodynamic rationale but the surgical risks, the fear of later portal deprivation encephalopathy and the difficulties of performing technically satisfactory anastomosis have discouraged many surgeons. Warren's distal spleno-renal shunt, selectively decompress esophageal varices and cures hypersplenism while sparing the spleen and providing a high flow anastomosis. We have used this operation in three patients with extrahepatic PH. All patients ceased bleeding and had their spleen size reduced with normal function.

The area under pH curve: a single-figure parameter representative of esophageal acid exposure

This investigation aims at providing simpler methods for reading esophageal extended pH-metering tracings. Because the currently used parameters only quantify frequency and duration of acid exposure, we have measured the area between the pH curve and the pH 4 line (area under curve [AUC]) in an attempt to include in the evaluation the severity of acid exposure as well. We compared 20 control and 63 children with gastroesophageal reflux (GER). Extended pH metering curves were read according to currently accepted methods. In addition, we measured planimetrically total 24-hour AUC, AUC during daytime, AUC during sleep time, and total AUC excluding 2-hour postprandial periods. In spite of the very significant differences found between means of controls and GER patients for all variables considered, values overlapped widely. Receiver-operating characteristic (ROC) analysis indicated the best threshold values for differentiation of controls and GER patients and tested the diagnostic efficiency for each variable. We found that 24-hour AUC was the best comprehensive value (sensitivity = 1, specificity = 1) and that there was probably no use for fractional evaluation during selected periods of time. The optimum 24-hour AUC threshold value in the present conditions of measurement (paper speed, 0.25 cm/min; 1 pH unit, 2.5 cm) was 20 cm2. In order to facilitate comparison we propose using a pH-surface unit (pHSU) equal to recording speed (in cm/min) multiplied by vertical shift per 1 pH unit (in centimeters) (in this case, 0.25 x 2.5 = 0.625 cm2). A threshold value of 20 cm2 thus becomes 32 pHSU. A similar transformation will be adequate for any other recording conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

[False negatives in pH measurement. A retrospective study of 12 surgical cases]

Extended esophageal pH-metering is the best method for GER diagnosis, but it has a certain number of false negatives. In a attempt to judge in which extent we can indicate surgery with a "normal" pH-metering study, we have reviewed our 110 operated children since 1982, and selected 12 in whom pH studies were normal. There where five females and seven males with ages ranging between 18 and 90 months. The clinical course until the diagnosis was accepted was long. Nine patients had vomiting, five respiratory disease, six dysphagia, four anemia and three torticollis. Only two were malnourished. There was radiologic GER in all children (with only one hiatal hernia). In spite of "normal" pH-metering, eight had decreased lower esophageal sphincter, and 11 disturbed motility. Nine had endoscopic esophagitis and eight histologic esophagitis. After operation, indicated only after long periods of medical treatment, vomiting disappeared in all, and so did respiratory disease and torticollis. Five families were very satisfied, six rather satisfied (gas bloat syndrome) and one frankly dissatisfied (dysphagia with severe immotility). Based on this evidence, we believe that some limited indications for surgery in GER are acceptable even in the presence of "normal" pH-studies.

[Pulmonary sequestration with esophagobronchial fistula. Presentation of 2 cases and a review of the literature]

Pulmonary sequestrations communicating with the gastrointestinal are very uncommon respiratory malformations. We report two personal cases and review 33 more previously published of which 24 were intralobar and 11 extralobar. We demonstrate that this malformation can hardly be separated from "classical" pulmonary sequestrations (ie, those without g.i. communication) a fact attesting their common embryologic origin. In extralobar sequestrations there were no differences in sex, side or associated malformations. In intralobar cases there were female (83%) and right side (67%) predominances, that are not observed in sequestrations without g.i. communication. We call the attention on the great variety of anatomic forms and on the great difficulty to reach an accurate anatomic diagnosis preoperatively.

[Clinical and pH-measured study of gastroesophageal reflux in children with respiratory manifestations]

In an attempt to clarify whether gastroesophageal reflux (GER) accounts for some respiratory manifestations (RM) we have measured 55 variables of extended distal esophageal pH metering in 70 children with both GER and RM, in 31 with GER only and in 10 controls. Patients in the first group were followed up after GER cure (either medical or surgical) and divided into two subgroups according to persistence or relief/cure of their RM. The best predictor of good respiratory results was a mean duration of nocturnal episodes of GER longer than 5'26". Patients who, in addition, had a history of vomiting and did not suffer from bronchospasm had 95% chances of having permanent cure of their RM after GER treatment.