Evaluation of vitamin-producing and immunomodulatory lactic acid bacteria as a potential co-adjuvant for cancer therapy in a mouse model

AIMS

To evaluate a mixture of selected lactic acid bacteria (LAB) (a riboflavin-producer, a folate-producer and an immunomodulatory strain) as co-adjuvant for 5-fluorouracil (5-FU) chemotherapy in cell culture and using a 4T1 cell animal model of breast cancer.

METHODS AND RESULTS

The viability of Caco-2 cells exposed to 5-FU and/or LAB was analysed. Mice bearing breast tumour were treated with 5-FU and/or LAB. Tumour growth was measured. Intestinal mucositis (IM) was evaluated in small intestine; haematological parameters and plasma cytokines were determined. The bacterial mixture did not negatively affect the cytotoxic activity of 5-FU on Caco-2 cells. The LAB mixture attenuated the IM and prevented blood cell decreases associated with 5-FU treatment. Mice that received 5-FU and LAB mixture decreased tumour growth and showed modulation of systemic cytokines modified by both tumour growth and 5-FU treatment. The LAB mixture by itself delayed tumour growth.

CONCLUSIONS

The mixture of selected LAB was able to reduce the side-effects associated with chemotherapy without affecting its primary anti-tumour activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

This bacterial mixture could prevent the interruption of conventional oncologic therapies by reducing undesirable side-effects. In addition, this blend would provide essential nutrients (vitamins) to oncology patients.

Recent update on lactic acid bacteria producing riboflavin and folates: application for food fortification and treatment of intestinal inflammation

Lactic acid bacteria (LAB), widely used as starter cultures for the fermentation of a large variety of food, can improve the safety, shelf life, nutritional value and overall quality of the fermented products. In this regard, the selection of strains delivering health-promoting compounds is now the main objective of many researchers. Although most LAB are auxotrophic for several vitamins, it is known that certain strains have the capability to synthesize B-group vitamins. This is an important property since humans cannot synthesize most vitamins, and these could be obtained by consuming LAB fermented foods. This review discusses the use of LAB as an alternative to fortification by the chemical synthesis to increase riboflavin and folate concentrations in food. Moreover, it provides an overview of the recent applications of vitamin-producing LAB with anti-inflammatory/antioxidant activities against gastrointestinal tract inflammation. This review shows the potential uses of riboflavin and folates producing LAB for the biofortification of food, as therapeutics against intestinal pathologies and to complement anti-inflammatory/anti-neoplastic treatments.

Effect of riboflavin-producing bacteria against chemically induced colitis in mice

AIM

To assess the anti-inflammatory effect associated with individual probiotic suspensions of riboflavin-producing lactic acid bacteria (LAB) in a colitis murine model.

METHODS AND RESULTS

Mice intrarectally inoculated with trinitrobenzene sulfonic acid (TNBS) were orally administered with individual suspensions of riboflavin-producing strains: Lactobacillus (Lact.) plantarum CRL2130, Lact. paracasei CRL76, Lact. bulgaricus CRL871 and Streptococcus thermophilus CRL803; and a nonriboflavin-producing strain or commercial riboflavin. The extent of colonic damage and inflammation and microbial translocation to liver were evaluated. iNOs enzyme was analysed in the intestinal tissues and cytokine concentrations in the intestinal fluids. Animals given either one of the four riboflavin-producing strains showed lower macroscopic and histologic damage scores, lower microbial translocation to liver, significant decreases of iNOs+ cells in their large intestines and decreased proinflammatory cytokines, compared with mice without treatment. The administration of pure riboflavin showed similar benefits. Lact. paracasei CRL76 accompanied its anti-inflammatory effect with increased IL-10 levels demonstrating other beneficial properties in addition to the vitamin production.

CONCLUSION

Administration of riboflavin-producing strains prevented the intestinal damage induced by TNBS in mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

Riboflavin-producing phenotype in LAB represents a potent tool to select them for preventing/treating IBD.

Evaluation of the effect of soymilk fermented by a riboflavin-producing Lactobacillus plantarum strain in a murine model of colitis

Inflammatory bowel diseases (IBD) are idiopathic diseases of the gastrointestinal tract characterised by recurrent inflammation that require lifelong treatments. It has been shown that certain strains of lactic acid bacteria (LAB) can produce specific health-promoting compounds in foods or in the gastrointestinal tract that can in turn prevent and/or treat IBD. This study was designed to evaluate the possible therapeutic potential of soymilk fermented by the riboflavin-producing strain Lactobacillus plantarum CRL 2130 in a trinitrobenzene sulfonic induced colitis mouse model. Mice that received soymilk fermented by L. plantarum CRL 2130 showed a decrease in weight loss, lower damage scores in their large intestines, lower microbial translocation to liver and decreased cytokines levels in their intestinal fluids compared to animals that received unfermented soymilk or soymilk fermented by a non-riboflavin-producing L. plantarum strain. This is the first report that demonstrates that a riboflavin-producing LAB was able to prevent experimental colitis in a murine model.

Prospective uses of recombinant Lactococcus lactis expressing both listeriolysin O and mutated internalin A from Listeria monocytogenes as a tool for DNA vaccination

In this study, Lactococcus lactis was engineered to express mutated internalin A on its surface and to secrete large amounts of listeriolysin O (LLO) in order to improve its potential as a vehicle for DNA vaccination. Western blotting experiments demonstrated that the bacterium expressed LLO in both the cytoplasmic and extracellular compartments, with higher quantities found in the culture supernatants. A hemolytic assay showed that the recombinant strain secreted 250 ng active LLO/mg total protein. This mInlA/LLO-producing strain of L. lactis may be used as an alternative tool in DNA vaccination against a number of infectious diseases or in cancer therapy.

B-group vitamin production by lactic acid bacteria--current knowledge and potential applications

Although most vitamins are present in a variety of foods, human vitamin deficiencies still occur in many countries, mainly because of malnutrition not only as a result of insufficient food intake but also because of unbalanced diets. Even though most lactic acid bacteria (LAB) are auxotrophic for several vitamins, it is now known that certain strains have the capability to synthesize water-soluble vitamins such as those included in the B-group (folates, riboflavin and vitamin B(12) amongst others). This review article will show the current knowledge of vitamin biosynthesis by LAB and show how the proper selection of starter cultures and probiotic strains could be useful in preventing clinical and subclinical vitamin deficiencies. Here, several examples will be presented where vitamin-producing LAB led to the elaboration of novel fermented foods with increased and bioavailable vitamins. In addition, the use of genetic engineering strategies to increase vitamin production or to create novel vitamin-producing strains will also be discussed. This review will show that the use of vitamin-producing LAB could be a cost-effective alternative to current vitamin fortification programmes and be useful in the elaboration of novel vitamin-enriched products.

A Thermostable α-Galactosidase from Lactobacillus fermentum CRL722: Genetic Characterization and Main Properties

Alpha-galactosidase (alpha-Gal) enzyme, which is encoded by the melA gene hydrolyzes alpha-1,6 galactoside linkages found in sugars, such as raffinose and stachyose. These alpha-galacto-oligosaccharides (alpha-GOS), which are found in large quantities in vegetables, such as soy, can cause gastrointestinal disorders in sensitive individuals because monogastric animals (including humans) do not posses alpha-Gal in the gut. The use of microbial alpha-Gal is a promising alternative to eliminate alpha-GOS in soy-derived products. Using degenerate primers, the melA gene from Lactobacillus (L.) fermentum CRL722 was identified. The complete genomic sequence of melA (2223 bp), and of the genes flanking melA, were obtained using a combination of polymerase chain reaction-based techniques, and showed strong similarities with the alpha-Gal gene of thermophilic microorganisms. The alpha-Gal gene from L. fermentum CRL722 was cloned and the protein purified from cell-free extracts of the native and recombinant strains using various techniques (ion exchange chromatography, salt precipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and ultra-filtration); Its main biochemical properties were determined. The enzyme was active at moderately high temperatures (55 degrees C) and stable at wide ranges of temperatures and pH. The thermostable alpha-Gal from L. fermentum CRL722 could thus be used for technological applications, such as the removal of alpha-GOS found in soy products. The complete melA gene could also be inserted in other micro-organisms, that can survive in the harsh conditions of the gut to degrade alpha-GOS in situ. Both strategies would improve the overall acceptability of soy-derived products by improving their nutritional value.

Ingestion of milk fermented by genetically modified Lactococcus lactis improves the riboflavin status of deficient rats

Riboflavin deficiency is common in many parts of the world, particularly in developing countries. The use of riboflavin-producing strains in the production of dairy products such as fermented milks, yogurts, and cheeses is feasible and economically attractive because it would decrease the costs involved during conventional vitamin fortification and satisfy consumer demands for healthier foods. The present study was conducted to assess in a rat bioassay the response of administration of milk fermented by modified Lactococcus lactis on the riboflavin status of deficient rats. Rats were fed a riboflavin-deficient diet during 21 d after which this same diet was supplemented with milk fermented by Lactoccus lactis pNZGBAH, a strain that overproduces riboflavin during fermentation. The novel fermented product, with increased levels of riboflavin, was able to eliminate most physiological manifestations of ariboflavinosis, such as stunted growth, elevated erythrocyte glutathione reductase activation coefficient values and hepatomegaly, that were observed using a riboflavin depletion-repletion model, whereas a product fermented with a nonriboflavin-producing strain did not show similar results. A safety assessment of this modified strain was performed by feeding rodents with the modified strain daily for 4 wk. This strain caused no detectable secondary effects. These results pave the way for analyzing the effect of similar riboflavin-overproducing lactic acid bacteria in human trials. The regular consumption of products with increased levels of riboflavin could help prevent deficiencies of this essential vitamin.

Reduction of alpha-galactooligosaccharides in soyamilk by Lactobacillus fermentum CRL 722: in vitro and in vivo evaluation of fermented soyamilk

AIMS

Consumption of soya-derived products has been hampered by the presence of alpha-galactooligosaccharides (alpha-GOS) because mammals lack pancreatic alpha-galactosidase (alpha-Gal) which is necessary for their hydrolysis. These sugars thus reach the large intestine causing gastrointestinal disorders in sensitive individuals. The use of lactic acid bacteria (LAB) expressing alpha-Gal is a promising solution for the degradation of alpha-GOS in soyamilk.

METHODS AND RESULTS

The capacity of the LAB Lactobacillus fermentum CRL 722 to properly degrade alpha-GOS was studied in vitro using controlled fermentation conditions and in vivo using a rat model. Lactobacillus fermentum CRL 722 was able to grow on commercial soyamilk and completely eliminated stachyose and raffinose during fermentation because of its high alpha-Gal activity. Rats fed soyamilk fermented by this LAB had smaller caecums compared with rats fed unfermented soyamilk.

CONCLUSIONS

Soyamilk fermentation by Lact. fermentum CRL 722 results in the reduction of alpha-GOS concentrations in soyamilk, thus eliminating possible undesirable physiological effects normally associated with its consumption.

SIGNIFICANCE AND IMPACT OF THE STUDY

Fermentation with Lact. fermentum CRL 722 could prevent gastrointestinal disorders in sensitive individuals normally associated with the consumption of soya-based products. This LAB could thus be used in the elaboration of novel fermented vegetable products which better suit the digestive capacities of consumers.

Effect of pH on Lactobacillus fermentum growth, raffinose removal, alpha-galactosidase activity and fermentation products

In this study, the behaviour of Lactobacillus fermentum CRL 722 and CRL 251 were evaluated under different pH conditions (pH 6.0, 5.5, 5.0, 4.5) and without pH control. Growth was similar under all conditions assayed except at pH 4.5. These microorganisms were able to eliminate raffinose, a nondigestible alpha-oligosaccharide (NDO) found in soy products, showing a consumption rate of 0.25 g l(-1) h(-1) (pH 6.0-5.0). The removal of raffinose was due to the high alpha-galactosidase (alpha-gal) activities of these lactic acid bacteria, which was highest at pH 5.5 (5.0 U/ml). The yield of organic acids produced during raffinose consumption was also highest at this pH. The results of this study will allow selection of the optimum growth conditions of L. fermentum with elevated levels of alpha-gal to be used in the reduction of NDO in soy products when used as starter cultures.

Immunomodulating effects of peptidic fractions issued from milk fermented with Lactobacillus helveticus

The effect of peptides released during the fermentation of milk on the humoral immune system and on fibrosarcoma growth was studied. Lactobacillus helveticus was able to release peptidic compounds during milk fermentation due to its high proteolytic activity, as was shown by the degree of proteolysis and size-exclusion HPLC elution profiles. Three fractions of these compounds were separated and fed to mice during different periods (2, 5, and 7 d). The humoral immune response was assessed by following the number of IgA-secreting cells, and the antitumor activity was monitored by studying the regression of subcutaneously implanted fibrosarcomas. Feeding during 2 and 7 d with the medium-sized fraction (Fraction II) significantly increased the IgA-producing cells in the intestines, whereas feeding with the large compound fraction (Fraction I) during 5 d and the small compound fraction (Fraction III) during all three feeding periods provided similar increases. A double dose of Fraction II showed the highest IgA-producing cell count. The increase by Fraction III was shown to be caused by the presence of L-Tryptophan. Fraction II significantly decreased the size of fibrosarcoma when previously fed during 7 d, and feeding with Fraction I during 5 d decreased significantly its size after 35 d of growth. Although the mechanisms by which lactic acid bacteria enhance the immune system are not clear, this study clearly shows that bioactive compounds released in fermented milks contribute to the immunoenhancing and antitumor properties of these products. The release of bioactive peptides by lactic acid bacteria can have important implications on the modulation of the cellular immune response.

Effects of propofol on cerebral oxygenation during cardiopulmonary bypass in children

PURPOSE

Neurologic complications occur following cardiopulmonary bypass surgery. We conducted a randomized, controlled, single-blind study to determine the effect of propofol on the redox status of cytaa3, and to evaluate its potential for decreasing neurologic complications.

METHODS AND MATERIALS

Twenty-four children (median age: 3.3 yr; median weight: 14.4 kg) scheduled for elective cardiopulmonary bypass surgery were assigned to either the experimental group (Group P, given sufficient propofol to eliminate brain electrical activity as measured on EEG (i.e. burst suppression)) or the control group (Group C, no propofol). Near infrared spectroscopy data were collected at one-second intervals throughout the surgical procedures. Pre- and postoperative neurologic examinations were completed by a physician blinded to the group to which the patient was assigned. Change in cytochrome aa3 data at 10-min intervals (10, 20, 30, 40 min) following start of bypass were compared between groups by repeated measures analysis of variance.

RESULTS

The patterns of change in redox state of cytochrome were different between the two groups (P < 0.002). The pattern of change within Group P was similar to that in hypothermic patients in Group C. There were correlations between change in cytaa3 redox status and temperature in the control subjects. There were no gross neurologic complications in either group.

CONCLUSIONS

Propofol appears to stabilize the energy supply/demand equilibrium of the brain during cardiopulmonary bypass surgery and thus theoretically could reduce the incidence or severity of neurologic complications.

The evolution of ductus arteriosus treatment

The treatment of patent ductus arteriosus (PDA) has evolved over the years. We reviewed 231 non-premature children (group 1) undergoing surgical closure of a PDA between January 1985 and December 1997, and 30 children (group 2) undergoing transcatheter closure from May 1995 to December 1998. The median age and weight at operation in group 1 were 13 months (range, 0.5-174 months) and 9.5 kg (range, 1.9-49.7 kg), respectively. There was one intra-operative death (0.4%) secondary to hemorrhage. Immediate extubation was performed in 208 patients (90%). Intra-operative chest tube use decreased from 73.3% to 10% between the 1985-88 and 1996-97 periods (P < 0.001). Postoperative pneumothoraces occurred in 33/131 (25%) patients with only one patient (0.7%) requiring drainage. Eleven patients had complications including wound infection in four, vocal cord paralysis in three, and left pulmonary artery stenosis in one. The median length of stay (LOS) was 5 days (range, 2-43 days). Follow-up echocardiogram was performed in 146/230 patients (63%) and revealed a residual PDA in six (4%); two being re-ligated, two remaining clinically insignificant, and two spontaneously resolved at 7 and 28 months follow-up. The remaining 84 patients had no clinical signs of a residual PDA. In group 2, where a transcatheter coil occlusion technique was used, the median age and weight at procedure were 31 months (range, 9-320 months) and 14.9 kg (range, 9-69.7 kg), respectively. Vascular complications occurred in four patients (13.3%). One patient developed hemolysis and hemoglobinuria requiring hospital admission. Four patients required a second intervention. At the most recent echocardiographic assessment, four patients (13.3%) had a residual PDA.

Intermediate follow-up of right ventricular outflow tract reconstruction with allograft conduits

BACKGROUND

Allograft conduits are among many varieties of material used for right ventricular outflow tract reconstruction. They invariably need to be replaced due to growth of the patient or conduit failure.

METHODS

From June 1984 to June 1996, a total of 76 patients underwent reconstruction of the right ventricular outflow tract with an allograft conduit: 51 aortic and 25 pulmonary. The median age, weight and conduit size at surgery were 37 months (range, 0.2 to 228 months), 12.4 kg (range, 2.9 to 61.4 kg), and 17 mm (range, 8 to 26 mm), respectively.

RESULTS

The hospital mortality was 5.3% (4 of 76 patients) and 2 patients died at 9 and 78 months follow-up. The median follow-up was 61 months (range, 2 to 132 months). Reoperation was necessary in 22 patients (28.9%) at a median interval of 50.5 months (range, 3 to 109 months) and the median conduit size was 21 mm (range, 12 to 23 months). There was no mortality. Freedom from reoperation at 64 months was 49.5% for conduits 15 mm and smaller, and 73.3% for conduits 16 mm and larger. Analysis by age shows freedom from reoperation at 64 months of 49.4% and 74.5% for patients younger than and older than 2 years, respectively. At 54 months there was no statistical difference in freedom from reoperation between pulmonary and aortic allografts.

CONCLUSION

Right ventricular outflow tract reconstruction with allograft conduits results in a high reoperation rate at 4 years but provides significantly longer freedom from reoperation with conduits larger than 15 mm or in patients over 24 months of age.

Risks of repeat sternotomy in pediatric cardiac operations

BACKGROUND

Repeat sternotomy has been associated with increased perioperative risks.

METHODS

We reviewed 165 patients undergoing 192 repeat sternotomies between January 1985 and January 1997 (group 1) and a control group of 184 patients (group 2). The operations in group 1 were valve procedures in 94 patients, Fontan procedure in 46, ventricular septal defect closure in 10, pulmonary arterioplasty in 17, and others in 25; in group 2 ventricular or atrial septal defect closure in 120 patients, tetralogy of Fallot repair in 26, valve procedures in 16, bidirectional Glenn anastomosis in 7, repair of transposition of the great arteries in 7, pulmonary arterioplasty in 4, and others in 4.

RESULTS

The hospital mortality was 2.6% in group 1 and 3.8% in group 2. Cardiac laceration occurred in 10 of 192 patients (5.2%), requiring emergent femorofemoral bypass in 6 patients. Two patients sustained an air embolism that was successfully treated with a hyperbaric chamber. Median total blood loss and requirements were not significantly different between the two groups. The length of stay in the intensive care unit and in the hospital were 4 days (range, 1 to 80 days) and 11 days (range, 1 to 135 days) in group 1, and 2 days (range, 1 to 87 days) and 7 days (range, 1 to 131 days) in group 2 (p < 0.02 and p < 0.002, respectively). The rate of complications was not significantly different in group 1 versus group 2. Overall survival was 97% (group 1) and 95% (group 2) at 120 months' follow-up (not significant).

CONCLUSIONS

With careful surgical technique and judicious use of femorofemoral bypass, the risk of repeat sternotomy is minimized.

Pediatric cardiac surgery in the 1990s

Future developments in the repair of these complex anomalies will rely heavily on a complete understanding of present results, which can be achieved only with attention to detail and rigorous standards. Results must be continually updated and management changes carefully planned and then critically examined for significant differences. Thus, the day-to-day care of patients with congenital heart disease must withstand careful scrutiny, both for consistency and for end results.

Extracardiac Fontan operation with tube fenestration allowing transcatheter coil occlusion

A fenestration may improve the immediate postoperative course after a Fontan procedure by preserving the cardiac output. We describe a simple and safe technique of fenestration amenable to coil occlusion, which can be carried out in most cardiac catheterization laboratories.

Management of pulseless pink hand in pediatric supracondylar fractures of humerus

Thirteen (3.2%) of 410 patients seen in British Columbia's Children's Hospital in Vancouver from January 1984 to September 1992 with supracondylar fractures did so with an absence of a radial pulse in an otherwise well perfused hand. A combination of segmental pressure monitoring, color-flow duplex scanning, and magnetic resonance angiography (MRA) appears to be a valid, noninvasive, and safe technique in evaluating patency of the brachial artery and collateral circulation across the elbow. Based on this study, early revascularization of a pulseless otherwise well-perfused hand in children with type 3 supracondylar fractures, although technically feasible and safe, has a high rate of asymptomatic reocclusion and residual stenoses of the brachial artery. Therefore a period of close observation with frequent neurovascular checks should be completed before more invasive correction of this problem is contemplated.

Effect of glutamate-aspartate reperfusion on postischemic neonatal myocardium

OBJECTIVE

We postulated that L-glutamate- and L-aspartate-enriched perfusate would improve functional recovery of postischemic neonatal rabbit hearts.

METHODS

Isolated working neonatal rabbit hearts were perfused with Krebs-Henseleit buffer and then subjected to 1 hour of hypothermic cardioplegic arrest with St. Thomas' Hospital solution. Hearts were then reperfused with L-glutamate- and L-aspartate-enriched (20 mmol/L) Krebs-Henseleit buffer (AA-enriched Krebs-Henseleit buffer). Hearts reperfused with Krebs-Henseleit buffer alone acted as controls (experiment A). Another group of hearts underwent a similar protocol but were reperfused with the AA-enriched Krebs-Henseleit buffer with correction of the sodium content (experiment B).

RESULTS

Hearts reperfused with AA-enriched Krebs-Henseleit buffer showed a significant decrease in aortic flow at both 15 (p = 0.04) and 30 (p = 0.025) minutes compared with controls. Arrhythmias were frequent. Sodium content of the AA-enriched Krebs-Henseleit buffer was 174 +/- 0.5 mmol/L. In experiment B, hearts reperfused with the AA-enriched Krebs-Henseleit buffer with correction of the sodium content exhibited no difference in aortic flow and cardiac output at either 15 or 30 minutes (p = 0.95 and 0.5 and 0.48 and 0.78, respectively) compared with controls. No arrhythmias were observed. The sodium content of the AA-enriched Krebs-Henseleit buffer was 146 +/- 0.7 mmol/L.

CONCLUSIONS

A beneficial effect on functional recovery of neonatal hearts reperfused with AA-enriched Krebs-Henseleit buffer was not demonstrated.

Peritoneal dialysis in children after cardiopulmonary bypass

OBJECTIVE

We reviewed 5 years' experience with peritoneal dialysis in children with acute renal failure after cardiac operations. We hypothesized that peritoneal dialysis is safe and effective in children with low-output cardiac failure after cardiac operations.

RESULTS

Mortality in these patients with renal failure (n = 32) was 46.9%. Fluid removed by peritoneal dialysis was 48 +/- 28 ml/kg per 24 hours. Most complications of peritoneal dialysis were minor, hyperglycemia being the most frequent (53.1%). Peritoneal infection was suspected in 25%. Bowel perforation developed in two patients. None of the complications required early termination of dialysis. Hemodynamics and pulmonary function improved continuously during the study period.

CONCLUSION

The early institution of peritoneal dialysis in acute renal failure and low cardiac output after cardiac operations not only removes fluid, thus easing fluid restriction, but may also improve cardiopulmonary function.

Influence of bidirectional superior cavopulmonary anastomosis on pulmonary arterial growth

Right-sided BSCA provides for satisfactory pulmonary arterial growth in infants and children with complex congenital heart defects, and it could enhance the growth of a small right pulmonary artery. The growth of the left pulmonary artery, particularly in younger patients, needs close attention to confirm the safe role of BSCA in long-term palliation.

Influence of competitive pulmonary blood flow on the bidirectional superior cavopulmonary shunt. A multi-institutional study

BACKGROUND

It is common practice to interrupt all alternative sources of pulmonary blood flow ("competitive flow") at the time of a bidirectional superior cavopulmonary anastomosis (BCPA), although the merits of this have not been systematically studied.

METHODS AND RESULTS

We reviewed the early and medium-term clinical and hemodynamic findings in 108 consecutive patients 3 weeks to 25 years old (median, 1.9 years) undergoing BCPA at one of three institutions. Preoperatively, pulmonary blood flow was dependent on antegrade ventricular flow (n = 50), systemic-to-pulmonary shunts (n = 33), or mixed sources (n = 25). Postoperatively, competitive sources of pulmonary blood flow were left patent in 43 of 108 patients (40%). There were four early (3.7%) and four late deaths, none related to persistence of competitive flow. After BCPA, patients with competitive flow had significantly higher systemic oxygen saturations at 1 hour (85% versus 79%), 24 hours (84% versus 78%), and at hospital discharge (84% versus 78%) and required a shorter period of artificial ventilation (median, 9 versus 24 hours) and intensive care (median, 2 versus 4 days). Oxygen saturations at late follow-up (median, 2.8 years; range, 1 to 7) did not differ (83% versus 82%). No patient developed pulmonary arteriovenous malformations.

CONCLUSIONS

Competitive flow is well tolerated in the short and medium term after BCPA, and early postoperative systemic oxygen saturations are improved. The long-term influence of competitive flow on pulmonary arterial growth, arteriovenous malformation development, and ventricular function warrants investigation.

Role of transesophageal echocardiography in the management of aortic-left ventricular tunnel

A 10-year-old patient has been followed for 10 years after repair of an aortic-left ventricular tunnel (ALVT) for residual aortic regurgitation and significant recurrent leak through the ALVT. Transesophageal echocardiography (TEE) was done prior to surgery and intraoperatively to (1) clarify the precise anatomy of the ALVT, (2) evaluate the degree of aortic regurgitation, and (3) assess the repair. Delineation of the anatomy of the ALVT and assessment of the residual aortic insufficiency helped with the intraoperative decision-making. We describe the TEE findings of a residual ALVT in this patient and discuss the role of TEE in managing the lesion.

Pulmonary artery banding is not contraindicated in double inlet left ventricle with transposition and aortic arch obstruction

It has been widely stated that pulmonary artery banding (PAB) is contraindicated in the setting of double inlet left ventricle with transposition of the great vessels (DILV/TGA), especially if aortic arch obstruction is present. We postulated that the poor results for this condition reflect the tendency to leave the band in place long-term without early recognition and relief of subaortic stenosis (SAS). Short-term PAB with early relief of SAS remains an attractive option compared to a neonatal "Norwood" strategy. We reviewed our results applying this approach to 18 consecutive infants presenting since 1980 with DILV/TGA and an obstructive anomaly of the aortic arch (coarctation 16, interruption or atresia 2). Four of the infants (22%) were considered to have important SAS at presentation. One underwent neonatal aortopulmonary connection and died. The remaining 17 patients underwent arch repair with PAB (median age 1.4 weeks; range 2 days-22 weeks) with one early death. The 16 survivors have been followed for 5.6 +/- 3.7 years. All but one ultimately developed SAS. Relief of SAS was performed in 15 patients (median age 8 months) using a proximal aortopulmonary anastomosis. There were two early deaths, and one late death. Thirteen of the 18 patients (72%) are alive and well, and 12 have achieved Fontan repair or bidirectional superior cavopulmonary anastomosis (BCPA) with persistent relief of SAS. Most patients with DILV/TGA and aortic arch obstruction will tolerate temporary PAB with adequate protection of the pulmonary vascular bed. Our current approach (in the absence of severe SAS at presentation) is PAB at the time of arch repair, followed by careful surveillance for, and early relief of, SAS combined with BCPA in infancy.

Systolic and diastolic function in tricuspid valve atresia before the Fontan operation

Systolic and diastolic function were assessed at preoperative cardiac catheterization in 6 patients with classic tricuspid atresia and were compared with those in control subjects. All patients had systemic-to-pulmonary shunts. Left ventricular end-systolic and end-diastolic volumes and masses were significantly larger in the patient group; stroke volume and the ratio of volume to mass were also higher, but not significantly. Mean end-diastolic, peak systolic and end-systolic pressures were similar. Mean stress at end-systole and peak systole were significantly higher in the patient group. Operant chamber stiffness tended to be lower than normal, but was not statistically significant, and myocardial stiffness was normal for the patient group also. Indexes of systolic function were compared. The rate-corrected mean velocity of fiber shortening in the patient group was lower and its relation with stress at end-systole was variable with 4 abnormal patients. The ratio of stress at end-systole/end-systolic volume was significantly lower in patients. The duration of hospital stay did not correlate with end-diastolic volume or any parameter. Thus, this study found abnormalities of load-dependent and independent indexes of systolic function with normal diastolic function in young preoperative patients with tricuspid atresia.

Giant hydatid lung cysts in the Canadian northwest: outcome of conservative treatment in three children

Hydatid lung disease due to Echinococcus granulosus in the Canadian northwest and Alaska is often asymptomatic and usually benign. We reviewed the course and outcome of three children with giant hydatid lung cyst seen over a 2-year period. All were North American Indian children aged 9 to 12 years who presented with cough, fever, and chest pain. One had a rash. There was a history of exposure to domestic dogs who had been fed moose entrails in each case. Chest x-rays showed solitary lung cysts with air-fluid levels, from 6 cm to 12 cm in diameter. Aspiration of each cyst demonstrated Echinococcus hooklets and protoscolices. Serology was unhelpful, being negative in two cases. Transient pneumonitis and pneumothorax were seen as complications of needle aspiration. Two cysts gradually resolved over the following 6 months. One child returned after 9 months with a lung abscess due to superimposed infection of the cyst remnant with Haemophilus influenzae, and eventually required lobectomy. The existence of an endemic benign variant of E granulosus in Canada is not widely known, and it is important to distinguish it from the more aggressive pastoral form of the disease seen in immigrants from sheep-rearing countries. The native Canadian disease usually resolves spontaneously, does not cause anaphylaxis, and does not implant daughter cysts if spilled. Surgical treatment should be avoided except for complications such as secondary bacterial infection.

Lung volumes, mechanics, and perfusion after pulmonary resection in infancy

Partial pulmonary resection in early childhood is well tolerated. Although long-term outcome has been described in several follow-up studies, almost no information is available on postoperative lung perfusion. We studied 14 patients 3 to 20 years (mean, 11.6 years) after they underwent partial pulmonary resection at 1 week to 30 months of age (mean, 6.8 months). We examined development, pulmonary function, endurance, radiographs and ventilation-perfusion scans. We used predicted pulmonary function test values, which were corrected for the relative amount of lung removed and called predicted-corrected values. We hypothesized that the remaining lung would have altered ventilation-perfusion characteristics. We found no abnormalities in the patients' physical development. Most children had abnormal regional ventilation, but normal equilibration occurred; five patients had gas retention; all had decreased perfusion to the area of resection; nine patients showed ventilation-perfusion mismatch characterized by dead-space ventilation. Lung volumes were within the predicted range in 12 patients. Residual volume and functional residual capacity were larger than predicted-corrected values in most patients but residual volume in relation to total lung capacity was at or below normal in 6 of 11 and did not correlate with the amount of lung removed. Most patients had prolonged expiratory flows. We conclude that lung resection in early childhood leads to good functional recovery. However, decreased expiratory flows, regional ventilation abnormalities, and decreased perfusion suggest dysplastic parenchyma and vascular bed in the area of resection.

Antiplatelet therapy in children with left-sided mechanical prostheses

Valve replacement in children has always been associated with a high mortality, outgrowth of the prosthetic valve and difficulty in managing anticoagulation. Between January 1985 and April 1991, 20 patients (14 males and 6 females) underwent replacement of a left-sided cardiac valve. The median age at diagnosis was 21.6 months (1 to 120 months) and the median age at surgery was 85 months (11 to 213 months). Six patients were under 4 years of age. The site of valve replacement was aortic in 11 patients and left atrioventricular (AV) valve in 9 patients. The indications for aortic valve replacement were stenosis (6) and incompetence (5). The left AV valve was replaced in three patients following repair of AV septal defect, in one patient with corrected transposition of the great arteries (LTGA), in one patient with severe dysplasia and insufficiency, and in four patients for congenital mitral stenosis. A Bjork-Shiley prosthesis was used in three mitral and one aortic position, all the other patients receiving a St. Jude prosthesis: six mitral and ten aortic. All patients were anticoagulated (warfarin) for 3 months post implantation and then switched to a regimen of aspirin and persantine. There was no early or late death. Median follow-up was 12.3 months (4 to 72 months). Total follow-up was 59 patient-years or 708 months. There was one incident of thromboembolism (1.7%/patient-year) and four instances of bleeding (6.8%/patient-year). There was no valve thrombosis. Our regime of early warfarin followed by long-term antiplatelet therapy has been associated with a low incidence of thromboembolism and no valve thrombosis.

Rhabdomyosarcoma arising within congenital pulmonary cysts: report of three cases

Over the past 9 months, three cases of primary pulmonary rhabdomyosarcoma have been treated at British Columbia Children's Hospital. Two patients (aged 24 and 37 months) presented with spontaneous pneumothoraces and had cystic changes in the affected lung on chest radiograph. The third patient (aged 42 months) was evaluated for chronic cough, fever, and failure to thrive. Chest x-ray showed a large mass in the left lower lobe as well as mediastinal adenopathy. All three of these lesions originated within congenital lung cysts, one a peripheral bronchogenic cyst and the others cystic adenomatoid malformations. This report suggests that there is a significant risk for the development of rhabdomyosarcoma within malformed pulmonary tissue.

Univentricular atrioventricular connection with subaortic stenosis: a staged surgical approach

A staged surgical approach was developed for the management of hearts with univentricular atrioventricular connection (double-inlet left ventricle or tricuspid atresia) and discordant ventriculoarterial connection with anatomical substrate for the development of subaortic stenosis. This consisted of initial palliation with pulmonary artery banding, followed by early elective relief of subaortic obstruction using a proximal pulmonary artery to ascending aorta anastomosis in infancy. Pulmonary blood flow was maintained at this time by creating a bidirectional superior cavopulmonary anastomosis. Over an 18-month period, 5 children, including 4 seen in the first week of life with aortic arch obstruction, were palliated with this approach. All patients survived operation and are asymptomatic with transcutaneous oxygen saturations of 80% to 85%. Completion of cavopulmonary repair is planned at 2 years of age. Although some authors have considered pulmonary artery banding contraindicated in these infants, the current staged approach offers an attractive alternative to the construction of a pulmonary artery to aorta anastomosis in the neonatal period.

Human clinical trials of the dilatable pulmonary artery banding prosthesis

OBJECTIVE

To test the hypothesis that the dilatable pulmonary artery banding prosthesis is as effective and safe to use as conventional fixed fabric bands, and provides an additional nonsurgical option for dilation.

DESIGN

Nonrandomized prospective human clinical trial.

SETTING

British Columbia's Children's Hospital for tertiary care.

PATIENTS

All patients admitted with congenital heart defects who required banding of the pulmonary artery during a 17 month period. The patients who received a dilatable band were selected on the basis of their cardiologist's preference.

INTERVENTIONS

Surgical banding was performed using accepted techniques. Intraluminal balloon dilation of the pulmonary artery band was done using techniques accepted for intraluminal balloon dilation in pulmonary valvuloplasty.

MAIN RESULTS

Eleven patients received the dilatable bands and eight received fixed bands. There was no evidence of failure of the bands to maintain their function. One patient required intraluminal balloon dilation of the dilatable band. This was successfully accomplished without complication. The dilatable bands were easier to remove than the fixed bands, but required greater surgical dexterity to place and adjust. One of the dilatable bands was applied too distally and one too tightly. One fixed band was applied too tightly and another too loosely, requiring a second banding operation.

CONCLUSIONS

The dilatable pulmonary artery banding prosthesis is as effective and safe to use as a fixed fabric band. It is easier to remove and provides a nonsurgical option for dilation.

Partial anomalous pulmonary venous return

Anomalous pulmonary venous return from the left lung is an extremely rare condition that is reported sporadically and in general in case reports. From 1964 through 1988, we identified 13 patients with this condition, all of whom underwent surgical correction. This represents the single largest reported institutional experience with this anomaly. The patients ranged in age from 15 months to 40 years. Seven were asymptomatic, and six had symptoms ranging from recurrent pulmonary infection to moderate congestive heart failure. Six had anomalous venous return from the entire left lung, and seven had anomalous return from the upper lobe only. Eight of the patients had associated cardiovascular anomalies. Four of the patients underwent surgical correction via a sternotomy approach with cardiopulmonary bypass to allow correction of coexisting intracardiac anomalies. The remaining patients underwent surgical repair through a left thoracotomy. The technique included high ligation and division of a persistent left superior vena cava with anastomosis to the left atrium at the site of partial excision of the atrial appendage. There were no deaths and only one complication in our series.

The clinical value and risks of lung biopsy in children with congenital heart disease

A retrospective review was made of 59 open lung biopsy specimens taken between 1984 and 1988 from children with congenital heart disease who were at risk for pulmonary vascular disease. Thirty-seven patients (ranging in age from 3.5 months to 23 years; median age, 14 months) had a primary left-to-right shunt (group A) and 22 patients (ages 1 to 15 years) had palliated cyanotic heart disease (group B). Forty-five of the lung biopsy specimens were requested as frozen sections. In both groups lung biopsy specimens were graded by the Heath-Edwards classification and correlated against preoperative hemodynamic data and outcome. In group A patients, carefully measured pulmonary vascular resistance and pulmonary/systemic vascular resistance ratio were reliable indicators of the structural state of the pulmonary vascular bed, obviating the need for routine lung biopsy. Pulmonary/systemic vascular resistance ratios greater than 0.45 accurately predicted all patients with irreversible pulmonary vascular disease, and pulmonary vascular resistance greater than 7 units.m2 accurately predicted all but one case of disease. Reversibility of pulmonary vascular changes is not synonymous with immediate postoperative survival: Fatal postoperative pulmonary hypertensive crises occurred in the presence of reversible pulmonary disease. Of those considered for the Fontan procedure, a mean pulmonary artery pressure less than 30 mm Hg and pulmonary vascular resistance less than 3 units.m2 correlated with Heath-Edwards grade I or normal lung biopsy results. In 36% of group B patients, reliable assessment of pulmonary vascular resistance could not be made, indicating a possible need for open lung biopsy procedures. When lung biopsy procedures were used as an isolated procedure, they were more dangerous (20% mortality, 13% morbidity) than previously reported. Intraoperative frozen sections are not adequate to accurately assess pulmonary vascular changes (9% error); serial paraffin sections are required.

Recurrent perigraft seroma treated by graft replacement with homograft iliac artery

A recurrent perigraft seroma complicating a polytetrafluoroethylene (PTFE) systemic-pulmonary artery shunt was successfully treated by replacement of the graft with a homograft iliac artery.

The use of cardiopulmonary bypass and circulatory arrest in the resection of massive tumors

This report describes our experience in five cases, removing a massive soft tissue tumor by means of placing the patient on cardiopulmonary bypass, with profound hypothermia and circulatory arrest. This technique allowed consideration to be given to the resection of tumors previously adjudged "inoperable."

Total anomalous pulmonary venous return with left heart hypoplasia

A term baby had a total anomalous pulmonary venous return to the inferior vena cava. The infant underwent complete repair, but died 30 hours after operation. The postmortem examination revealed severe endocardial fibroelastosis. This uncommon association is discussed.

Pulmonary artery banding: results and current indications in pediatric cardiac surgery

The results of pulmonary artery banding in 144 patients seen from 1971 to 1984 were reviewed. Age ranged from 1 week to 4 years (median, 8 weeks) and weight, from 1.1 to 16 kg (median, 4 kg). The patients were divided into three major groups: Group 1, defects without mixing disorders (ventricular septal defect, double-outlet right ventricle [DORV], atrioventricular septal defect); Group 2, defects with mixing disorders (transposition of the great arteries, DORV, single ventricle, tricuspid atresia); and Group 3, miscellaneous (mitral atresia, left ventricular hypoplasia, truncus complex). The diagnostic group influenced survival (p = 0.0035). In Group 1, 88.8% survived, but only 64.9% survived in Groups 2 and 3 combined. The presence of patent ductus arteriosus or coarctation of the aorta had no effect on survival (p = 0.61 and p = 0.7, respectively). The clinical condition at thirty days after pulmonary artery banding was good in 35.1% and fair in 46.9% of the patients. When the data were divided into the three periods 1971 through 1974, 1975 through 1979, and 1980 through 1984, which included 28, 49, and 67 patients, respectively, a significant improvement in survival was observed from the early (64.3%) to the late period (92.5%) (p = 0.0009). Patients weighing less than 4 kg had a significantly lower survival in the period 1971 through 1974 (37.5% versus 91.67%). No significant difference in survival was detected in the late period, 1980 to 1984 (90% versus 94.6%), between patients weighing less than and those weighing more than 4 kg. Pulmonary artery banding is clinically satisfactory in small infants and children with complex anomalies.

Perigraft seroma: long-term complications

A 5 1/2-year-old child is described in whom a perigraft seroma complicating a polytetrafluoroethylene tubular graft was managed conservatively for 4 years without disruption of the function of the graft or progressive distortion of the pulmonary arteries.

Treatment of grafts and major vessel thrombosis with low-dose streptokinase in children

Low-dose streptokinase infusions have been used in 8 of our patients. Five of these were newborns who had major vessel occlusion. Four babies had extensive aortic thrombosis and hypertension producing congestive aortic thrombosis and hypertension producing congestive heart failure. One baby had caval and renal vein thrombosis and was in renal failure. Two infants with cyanotic heart disease and 1 with arteritis had occluded prosthetic grafts, which were reopened completely. Two grafts were between the subclavian and pulmonary arteries (Blalock-Taussig shunt), and one was between the abdominal aorta and right renal artery. In each patient, the thrombolytic agent was delivered directly to the area of thrombosis by three or four percutaneously inserted French catheters. The dose of streptokinase used was between 50 and 100 U/kg/hr. Therapy lasted for 2 to 11 days. Major bleeding was anticipated, and it occurred in 1 patient. Low-dose streptokinase infusion is a safe and effective treatment for a variety of thrombotic problems in infants and children.

Results of total correction in complete atrioventricular septal defects with congenital or surgically induced right ventricular outflow tract obstruction

The outcome of total repair in 29 children who had complete atrioventricular septal defect (AVSD) and congenital or surgically induced right ventricular outflow tract obstruction (RVOTO) is reviewed. All 11 patients with congenital RVOTO had normal pulmonary artery (PA) pressure before the complete repair. Of the 18 children who had undergone PA banding, seven had PA pressure above 30 mm Hg (mean, 53.5). Two had elevated pulmonary vascular resistance (greater than 3 units). Early mortality was 18.2% for the patients with congenital RVOTO and 44.4% for those who had undergone PA banding (p not significant). After a mean follow-up of 5 years, the results are good in the survivors of both groups. Analysis of multiple-risk factors indicate that, for the total group of patients, death was significantly more common in children less than 5 years of age (p less than 0.01) or less than 15 kg (p less than 0.02) than in older or larger patients.

Management of transposition after the baffes procedure: a case report and review of our experience

A case report details the operative technique used in the repair of complete transposition of the great arteries (TGA), ventricular septal defect (VSD), and pulmonary stenosis in a patient who had had Baffes procedure previously. Experience in managing 10 patients with complete TGA who had undergone a Baffes procedure is discussed. Four patients with a large VSD had pulmonary vascular disease. The condition of 1 of them was improved by a palliative Mustard operation. Four children with isolated TGA underwent a successful modified Mustard repair. The 2 remaining patients had a VSD and pulmonary stenosis; in 1 the condition was palliated by a Glenn shunt. The other is the subject of the case report. The mean interval between the Baffes procedure and the second operation was 11 years. There was 1 late death after secondary repair. Follow-up in the remaining 6 patients at a mean of 10.6 years indicates a favorable outcome.