The effect of high-pressure jet processing on cocoa stability in chocolate milk.

Fat-free chocolate milk formulations containing skim milk, cocoa powder, and sugar were thermally treated and then processed using high-pressure jet (HPJ) technology from 125 to 500 MPa. The rheological properties and stability of HPJ-treated chocolate milks were compared with controls (no HPJ processing) prepared both with and without added κ-carrageenan. As expected, carrageenan-free chocolate milk exhibited immediate phase separation of the cocoa powder, whereas formulations containing κ-carrageenan were stable for 14 d. An increased stability was observed with increasing HPJ processing pressure, with a maximum observed when chocolate milk was processed at 500 MPa. The apparent viscosity at 50 s-1 of HPJ-processed samples increased from ~3 mPa·s to ~9 mPa·s with increasing pressure, and shear-thinning behavior (n < 0.9) was observed for samples processed at HPJ pressures ≥250 MPa. We suggest that HPJ-induced structural changes in casein micelles and new casein-cocoa interactions increased cocoa stability in the chocolate milk. Because casein seemed to be the major component enhancing cocoa stability in HPJ-treated samples, a second study was conducted to determine the effect of additional micellar casein (1, 2, or 4%) and HPJ processing (0-500 MPa) on the stability of fat-free chocolate milk. Formulations with 4% micellar casein processed at 375 and 500 MPa showed no phase separation over a 14-d storage period at 4°C. The addition of micellar casein together with HPJ processing at 500 MPa resulted in a higher apparent viscosity (~17 mPa·s at 50s-1) and more pronounced shear-thinning behavior (n ≤ 0.81) compared with that without added micellar casein. The use of HPJ technology to improve the dispersion stability of cocoa provides the industry with a processing alternative to produce clean-label, yet stable, chocolate milk.

Technical note: development of a quantitative PCR method for monitoring strain dynamics during yogurt manufacture.

Yogurt starter cultures may consist of multiple strains of Lactobacillus delbrueckii ssp. bulgaricus (LB) and Streptococcus thermophilus (ST). Conventional plating methods for monitoring LB and ST levels during yogurt manufacture do not allow for quantification of individual strains. The objective of the present work was to develop a quantitative PCR method for quantification of individual strains in a commercial yogurt starter culture. Strain-specific primers were designed for 2 ST strains (ST DGCC7796 and ST DGCC7710), 1 LB strain (DGCC4078), and 1 Lactobacillus delbrueckii ssp. lactis strain (LL; DGCC4550). Primers for the individual ST and LB strains were designed to target unique DNA sequences in clustered regularly interspersed short palindromic repeats. Primers for LL were designed to target a putative mannitol-specific IIbC component of the phosphotransferase system. Following evaluation of primer specificity, standard curves relating cell number to cycle threshold were prepared for each strain individually and in combination in yogurt mix, and no significant differences in the slopes were observed. Strain balance data was collected for yogurt prepared at 41 and 43°C to demonstrate the potential application of this method.

Short communication: Identification and differentiation of bifidobacteria obtained from Ukraine.

Ten freeze-dried bifidobacterial strains used as probiotics in Ukrainian dairy foods, identified by the supplier as Bifidobacterium adolescentis (2), Bifidobacterium bifidum (2), Bifidobacterium longum (4), Bifidobacterium animalis (1), and Bifidobacterium infantis (1), were characterized. Following rehydration and anaerobic growth on de Man, Rogosa, and Sharpe-cysteine medium at 37°C for 72 h, single-colony isolates were picked and evaluated using PCR primers specific for the Bifidobacterium genus, for the supplier-identified species, and for B. animalis ssp. lactis. All isolates were identified as members of the genus Bifidobacterium; however, species-specific PCR revealed all 10 isolates were actually strains of B. animalis ssp. lactis. Further evaluation using pulsed-field gel electrophoresis was only able to separate a single strain (RT 09) from the other 9 strains evaluated. Application of genome-wide allelic profiling to the Ukrainian bifidobacterial strains revealed 4 distinct groups. Interestingly, 6 (60%) of the isolates fell into the same cluster as that containing the common commercial probiotic strain BB-12. Two of the strains (RT 02 and RT 09) were found to be in the same group as ATCC 27536 and one strain (RT 08) was in the same group as the RB 7239 (a previously evaluated commercial strain). One strain, RT 04, was placed on a unique branch. These results highlight the importance of employing routine typing of bifidobacterial isolates, demonstrate the utility of single nucleotide polymorphism/insertion-deletion polymorphism-based allelic typing in B. animalis ssp. lactis strain differentiation and further point to the limited genetic variability of B. animalis ssp. lactis strains and the worldwide distribution of a small number of commercial strains.

Short communication: the complete genome sequence of Bifidobacterium animalis subspecies animalis ATCC 25527(T) and comparative analysis of growth in milk with B. animalis subspecies lactis DSM 10140(T).

The objective of this work was to sequence the genome of Bifidobacterium animalis ssp. animalis ATCC 25527(T), the subspecies most closely related to B. animalis ssp. lactis, some strains of which are widely added to dairy foods as probiotics. The complete 1,932,963-bp genome was determined by a combination of 454-shotgun sequencing and PCR gap closing, and the completed assembly was verified by comparison with a KpnI optical map. Comparative analysis of the B. animalis ssp. animalis ATCC 25527(T) and B. animalis ssp. lactis DSM 10140(T) genomes revealed high degrees of synteny and sequence homology. Comparative genomic analysis revealed 156 and 182 genes that were unique to and absent in the B. animalis ssp. animalis genome, respectively. Among these was a set of unique clustered regularly interspaced short palindromic repeats (CRISPR)-associated genes and a novel CRISPR locus containing 30 spacers in the genome of B. animalis ssp. animalis. Although previous researchers have suggested that one of the defining phenotypic differences between B. animalis ssp. animalis and B. animalis ssp. lactis is the ability of the latter to grow in milk and milk-based media, the differential gene content did not provide insights to explain these differences. Furthermore, growth and acid production in milk and milk-based media did not differ significantly between B. animalis ssp. lactis (DSM 10140(T) and Bl04) and B. animalis ssp. animalis (ATCC 25527(T)). Growth of these strains in supplemented milk suggested that growth was limited by a lack of available low-molecular-weight nitrogen in the 3 strains examined.

Study to investigate the potential of probiotics in children attending school.

BACKGROUND/OBJECTIVES: To determine if consumption of yogurt containing a high dose of probiotic (1×10(10) colony-forming unit per 100 ml), Bifidobacterium animalis subsp. lactis (B. lactis), decreases absences in children 2-4 years attending daycare/school centers. SUBJECTS/METHODS: We conducted a double-blinded, randomized, placebo-controlled, allocation concealment clinical trial in the Washington, DC area. Our active intervention was a strawberry yogurt-based drink supplemented with B. lactis BB-12. The placebo was indistinguishable from the active drink, differing only in absence of the probiotic BB-12. RESULTS: A total of 172 children between the ages of 2 and 4 from the Washington, DC area were enrolled. The primary outcome, missed days of school because of illness per 100 days, was similar in both the active (2.54 days absent/100 school days) and control groups (2.42 days absent/100 school days) (P=0.873). CONCLUSIONS: The probiotic-containing yogurt-based beverage studied did not decrease absences because of illnesses in daycare/school for healthy children ages 2-4 years.

Cloning of genes encoding colicin E2 in Lactococcus lactis subspecies lactis and evaluation of the colicin-producing transformants as inhibitors of Escherichia coli O157:H7 during milk fermentation.

Colicin E2 (ColE2) is a proteinaceous bacterial toxin produced by some strains of Escherichia coli and other members of the Enterobacteriaceae that exhibits inhibitory activity against some strains of E. coli O157:H7. A 2.0-kb DNA fragment, containing the ColE2 structural gene ceaB and immunity gene ceiB from E. coli NCTC 50133 (pColE2-P9), was cloned into the lactococcal plasmid vector pNZ2103. The lysis gene, celB, was not cloned. The plasmid, pLR-E2, encoding the cloned genes was transformed into E. coli DH5α and Lactococcus lactis ssp. lactis LM0230 and PN-1 using electroporation. The bacteriocin ColE2 was expressed in transformants of both E. coli and L. lactis ssp. lactis. Secretion of ColE2 into media was verified by spot-on-lawn assays and measurement of ColE2 activity in the growth medium of transformants. The level of ColE2 produced by transformants containing pLR-E2 was similar to that produced by the parental strain, E. coli NCTC 50133 (pColE2-P9). Evaluation of a ColE2-producing transformant of L. lactis ssp. lactis as a starter culture revealed that, although ColE2 was produced by transformants and could be detected in milk during fermentation, the inhibitory activity of ColE2 against E. coli O157:H7 was significantly decreased in milk compared with buffered growth medium.

A simple method of supplementation of omega-3 polyunsaturated fatty acids: use of fortified yogurt in healthy volunteers.

BACKGROUND: A relative dietary ω-3 fatty acid deficiency exists in Western diets, and this deficiency may be associated with some chronic diseases. The aim of the present study was to supplement yogurt with docosahexaenoic acid and assess whether this fatty acid could be incorporated into plasma lipids. METHODS: We developed a stable emulsion of docosahexaenoic acid that was incorporated into yogurt. Twelve healthy volunteers agreed to consume 1 serving daily that contained 600 mg of docosahexaenoic acid. RESULTS: After 3 weeks of supplementation, plasma phospholipid docosahexaenoic acid content increased significantly, by 32%, in parallel with a 16% rise in total ω-3 fatty acids. This result was associated with a significant 7% decline in phospholipid arachidonic acid. CONCLUSIONS: Fortification of ordinary foods with docosahexaenoic acid is a potentially attractive method of increasing ω-3 fatty acid content of plasma lipids, and might even lower arachidonic acid concentrations.

Estrone and 17beta-estradiol concentrations in pasteurized-homogenized milk and commercial dairy products.

Some individuals fear that estrogens in dairy products may stimulate growth of estrogen-sensitive cancers in humans. The presence of estrone (E(1)) and 17beta-estradiol (E(2)) in raw whole cow's milk has been demonstrated. The objectives of this study were to determine if pasteurization-homogenization affects E(2) concentration in milk and to quantify E(1) and E(2) concentrations in commercially available dairy products. The effects of pasteurization-homogenization were tested by collecting fresh raw milk, followed by pasteurization and homogenization at 1 of 2 homogenization pressures. All treated milks were tested for milk fat globule size, percentages of milk fat and solids, and E(2) concentrations. Estrone and E(2) were quantified from organic or conventional skim, 1%, 2%, and whole milks, as well as half-and-half, cream, and butter samples. Estrone and E(2) were quantified by RIA after organic solvent extractions and chromatography. Pasteurization-homogenization reduced fat globule size, but did not significantly affect E(2), milk fat, or milk solids concentrations. Estrone concentrations averaged 2.9, 4.2, 5.7, 7.9, 20.4, 54.1 pg/mL, and 118.9 pg/g in skim, 1%, 2%, and whole milks, half-and-half, cream, and butter samples, respectively. 17Beta-estradiol concentrations averaged 0.4, 0.6, 0.9, 1.1, 1.9, 6.0 pg/mL, and 15.8 pg/g in skim, 1%, 2%, whole milks, half-and-half, cream, and butter samples, respectively. The amount of fat in milk significantly affected E(1) and E(2) concentrations in milk. Organic and conventional dairy products did not have substantially different concentrations of E(1) and E(2). Compared with information cited in the literature, concentrations of E(1) and E(2) in bovine milk are small relative to endogenous production rates of E(1) and E(2) in humans.

The study to investigate the potential benefits of probiotics in yogurt, a patient-oriented, double-blind, cluster-randomised, placebo-controlled, clinical trial.

BACKGROUND: Probiotic functional foods are widely advertised to consumers primarily based on probiotic supplements. OBJECTIVE: Determine if consumption of yogurt containing a high dose of probiotics improves health in children ages 1-3 years attending daycare/school centers. SUBJECTS/METHODS: Double-blinded, randomized, placebo-controlled, allocation concealment clinical trial. SETTING: Outpatient participants in the Washington, DC area. PARTICIPANTS: 182 healthy children between the age of 1 and 3 years attending daycare/school at least 3 days a week. INTERVENTION: Active was a strawberry yogurt-based drink supplemented with Bifidobacterium animalis ssp. lactis (B. lactis) BB-12. The placebo was indistinguishable from the active drink, differing only in absence of the probiotic BB-12. Primary objective was to determine if consumption of a probiotic-containing yogurt-based drink decreases absences due to illnesses from daycare for children ages 1-3 years. Secondary was to determine if probiotic-containing yogurt-based drink improves overall parental satisfaction due to decreased absences from work and an overall healthier child. RESULTS: There were no significant differences in the days of missed school per group, with 51.9% in the active group and 47.1% in the placebo group missing at least 1 day of school throughout the study. Additionally, there were no differences in any secondary outcomes among the groups. CONCLUSIONS: Consumption of a yogurt-based drink delivering 10(10) CFU of Bifidobacterium animalis ssp. lactis (B. lactis) BB-12 per day did not decrease the number of days missed of school due to an illness. Additional independent research on the potential of BB-12 to reduce illness in children needs to be conducted.

Transport of glucose by Bifidobacterium animalis subsp. lactis occurs via facilitated diffusion.

Two strains of Bifidobacterium animalis subsp. lactis were indistinguishable by several nucleic acid-based techniques; however, the type strain DSMZ 10140 was glucose utilization positive, while RB 4825, an industrially employed strain, was unable to grow rapidly on glucose as the principal carbon source. This difference was attributed to the presence of a low-affinity facilitated-diffusion glucose transporter identified in DSMZ 10140 but lacking in RB 4825. Uptake of D-[U-(14)C]glucose in DSMZ 10140 was stimulated by monovalent cations (ammonium, sodium, potassium, and lithium) and inhibited by divalent cations (calcium and magnesium). When competitor carbohydrates were included in the uptake assays, stereospecific inhibition was exhibited, with greater competition by methyl-beta-glucoside than methyl-alpha-glucoside. Significant inhibition (>30%) was observed with phloretin, an inhibitor of facilitated diffusion of glucose, whereas there was no inhibition by sodium fluoride, iodoacetate, sodium arsenate, sodium azide, 2,4-dinitrophenol, monensin, or valinomycin, which typically reduce energy-driven transport. Based on kinetic analyses, the mean values for K(t) and V(max) were 14.8 +/- 3.4 mM D-glucose and 0.13 +/- 0.03 micromol glucose/min/mg cell protein, respectively. Glucose uptake by several glucose-utilizing commercial strains of B. animalis subsp. lactis was also inhibited by phloretin, indicating the presence of facilitated diffusion glucose transporters in those strains. Since DSMZ 10140 has been previously reported to lack a functional glucose phosphoenolpyruvate phosphotransferase system, the glucose transporter identified here is responsible for much of the organism's glucose uptake.

Staphylococcal enterotoxin D production by Staphylococcus aureus FRI 100.

Staphylococcus aureus FRI 100 is commonly used as a control strain for staphylococcal enterotoxin A (SEA) assays. When FRI 100 was used in PCR-based enterotoxin detection methods, the strain gave a positive result for both SEA and staphylococcal enterotoxin D (SED). Production of SED was confirmed by testing concentrated and unconcentrated culture supernatants with the TECRA staphylococcal enterotoxin visual immunoassay. SED was detected after 24 h of growth in Trypticase soy broth. Primers were created to amplify the entire sed gene by PCR for subsequent sequencing. The sequenced gene showed high similarity to a previously sequenced sed gene. The SED-like gene in FRI 100 exhibited four point mutations and two deletions. Changes in the FRI 100 open reading frame altered the primary structure of the SED-like protein, allowing for coding of only the first 150 amino acids followed by a stop codon. Because the SED active site is at the proximal end, where there was no change in DNA sequence, we conclude FRI 100 produces a variant form of SED. It is necessary to note that, when using FRI 100 as an SEA control strain, it does produce a variant of the SED protein, which exhibits immunological activity, and the sed-like gene is detected by commonly used PCR primers. This phenomenon may be an important general consideration when using PCR to characterize strains of toxin-producing S. aureus. S. aureus enterotoxin-positive PCR results should be confirmed by immunological techniques.

Technical note: a rapid pulsed-field gel electrophoresis method for analysis of bifidobacteria.

Pulsed-field gel electrophoresis (PFGE) is a widely used and highly discriminatory molecular typing method that has been applied to bifidobacteria. However, published PFGE protocols used with bifidobacteria require between 5 and 7 d to complete. A rapid PFGE method was developed that can be completed within 24 h.

In vitro assessment of the cytotoxicity of nisin, pediocin, and selected colicins on simian virus 40-transfected human colon and Vero monkey kidney cells with trypan blue staining viability assays.

Gram-positive bacterial bacteriocins (nisin and pediocin) and gram-negative bacterial bacteriocins (colicins [Col] E1, E3, E6, E7, and K) were evaluated for cytotoxicity against cultured simian virus 40-transfected human colon (SV40-HC) and Vero monkey kidney (Vero) cells. Bacteriocin-treated cells were assessed for viability by trypan blue staining. Monolayers of SV40-HC and Vero cells were cultured in tissue culture plates (35 degrees C, 10% CO2 in humidified air) with the use of Dulbecco's modified Eagle's medium supplemented with 10% (vol/vol) calf serum. Actively growing cells in the log phase (ca. 10(4) cells per ml) were treated with individual partially purified bacteriocin preparations at 170, 350, and 700 activity units per ml. Duplicate culture plates for each bacteriocin treatment and untreated controls were withdrawn after 16, 32, and 48 h of incubation. Cells were dissociated with trypsin and treated with trypan blue and were then counted in a hemocytometer with the use of a phase-contrast microscope. Viability assays indicated dose-dependent toxicity for some bacteriocins. Nisin, pediocin, and Col E6 were the most cytotoxic bacteriocins; SV40-HC cells demonstrated greater sensitivity than Vero cells did. Some bacteriocins can be toxic to mammalian cells; therefore, bacteriocins intended for use as biopreservatives must be evaluated for toxicity to mammalian cells and for other toxicities. Col E1, Col E3, Col E7, and Col K demonstrated little toxicity at the activities tested, indicating that they are safe and thus have potential for use as food biopreservatives.

Production of an exopolysaccharide-containing whey protein concentrate by fermentation of whey.

Using whey as a fermentation medium presents the opportunity to create value-added products. Conditions were developed to partially hydrolyze whey proteins and then ferment partially hydrolyzed whey with Lactobacillus delbrueckii ssp. bulgaricus RR (RR; an EPS-producing bacterium). In preliminary experiments, pasteurized Cheddar cheese whey was treated with Flavourzyme to partially hydrolyze the protein (2 to 13% hydrolyzed). Fermentation (2 L, 38 degrees C, pH 5.0) with RR resulted in EPS levels ranging from 95 to 110 mg of EPS per liter of hydrolyzed whey. There were no significant differences in the amount of EPS produced during fermentations of whey hydrolyzed to varying degrees. Since a high level of hydrolysis was not necessary for increased EPS production, a low level of hydrolysis (2 to 4%) was selected for future work. In scale up experiments, whey was separated and pasteurized, then treated with Flavourzyme to hydrolyze 2 to 4% of the protein. Following protease inactivation, 60 L of partially hydrolyzed whey was fermented at 38 degrees C and pH 5.0. After fermentation, the broth was pasteurized, and bacterial cells were removed using a Sharples continuous centrifuge. The whey was then ultrafiltered and diafiltered to remove lactose and salts, freeze-dried, and milled to a powder. Unfermented hydrolyzed and unhydrolyzed whey controls were processed in the same manner. The EPS-WPC ingredients contained approximately 72% protein and 6% EPS, but they exhibited low protein solubility (65%, pH 7.0; 58%, pH 3.0).

Influence of sodium chloride on growth of lactic acid bacteria and subsequent destruction of Escherichia coli O157:H7 during processing of Lebanon bologna.

Due to undesirable quality changes, Lebanon bologna is often processed at temperatures that do not exceed 48.8 degrees C (120 degrees F). Therefore, it is important to study parameters that influence the destruction of Escherichia coli O157:H7 in Lebanon bologna. The objective of the present study was to determine the influence of curing salts (NaCl and NaNO2) on the destruction of E. coli O157:H7 during Lebanon bologna processing. Fermentation to pH 4.7 at 37.7 degrees C reduced populations of E. coli O157:H7 by approximately 0.3 log10, either in the presence or absence of curing salts. Subsequent destruction of E. coli O157:H7 during heating of fermented product to 46.1 degrees C was significantly reduced by the presence of 3.5% NaCl and 156 ppm NaNO2, compared to product without curing salts (P < 0.01). The presence of a higher level of NaCl (5%) in Lebanon bologna inhibited the growth of lactic acid bacteria (LAB), which yielded product with higher pH (approximately 5.0) and significantly reduced the destruction of E. coli O157:H7 even further (P < 0.05). Lower concentrations of NaCl (0, 2.5%) yielded Lebanon bologna with higher LAB counts and lower pHs, compared to product with 5% NaCl. When lactic acid was used to adjust pH in product containing different levels of NaCl, it was determined that low pH was directly influencing destruction of E. coli O157:H7, not NaCl concentration.

Platelet activating factor acetylhydrolase decreases lung reperfusion injury.

BACKGROUND: Ischemia-reperfusion injury involves free radical production, polymorphonuclear neutrophil chemotaxis/degranulation, and production of proteolytic enzymes, complement components, coagulation factors, and cytokines. Activated polymorphonuclear neutrophils, endothelial cells, and macrophages produce platelet activating factor, which further promotes these inflammatory reactions. The recently cloned plasma form of platelet activating factor-acetylhydrolase (PAF-AH) demonstrates antiinflammatory effects by degrading platelet activating factor. We evaluated the effects of PAF-AH in an isolated perfused rat lung model by adding it to the flush solutions or to the reperfusion blood. METHODS: Rat lungs were isolated, flushed with EuroCollins (EC) or University of Wisconsin (UW) solution, stored at 4 degrees C for 6 or 12 hours, and reperfused using a cross-circulating syngeneic support rat. During reperfusion, oxygenation, compliance, and capillary filtration coefficient were calculated. There were four groups in the study; group I (control) had no PAF-AH added, group II had PAF-AH added to the flush solution, group III had PAF-AH added to reperfusion blood, and group IV had PAF-AH added to both flush solution and reperfusion blood. RESULTS: After 6 hours of storage, oxygenation, compliance, and capillary filtration coefficient significantly improved for EC in group IV. For UW, oxygenation improved in group IV whereas compliance improved in groups II, III, and IV. After 12 hours of storage, compliance improved for EC in group IV and capillary filtration coefficient improved in groups III and IV. For UW, oxygenation and compliance improved in groups II and IV, whereas capillary filtration coefficient improved in group IV. CONCLUSIONS: Addition of PAF-AH to intracellular organ preservation solutions and to the blood reperfusate significantly improves postreperfusion oxygenation and compliance, and reduces lung capillary permeability.

Sirolimus (rapamycin) potentiates cyclosporine in prevention of acute lung rejection.

BACKGROUND: Cyclosporine-based immunosuppressive regimens (INN: ciclosporin) in human lung transplantation continue to result in a high incidence of acute cellular rejection. We investigated the use of sirolimus, a macrolide with structural similarity to tacrolimus, as monotherapy and in combination with cyclosporine in a rodent lung transplant model. METHODS: Orthotopic left lung transplantation was performed in Lewis recipients from Brown-Norway donor rats with syngeneic Lewis-to-Lewis controls. Open biopsies were performed on postoperative day 7, and the severity of acute lung rejection was graded by a pathologist blinded to the protocol. RESULTS: All recipients survived despite the amount of acute rejection seen on examination of the biopsy tissue. Lewis-to-Lewis isografts demonstrated near normal pulmonary architecture. Allogeneic recipients receiving high-dose cyclosporine (25 mg/kg) monotherapy showed mild to moderate acute rejection with some perivascular focal interstitial infiltrates. Recipients receiving low-dose cyclosporine (5 mg/kg) monotherapy or low- or high-dose sirolimus (0.5 or 2.0 mg/kg, respectively) monotherapy demonstrated massive cellular infiltration leading to necrosis and infarction and could not be graded. However, the addition of low-dose sirolimus (0.5 mg/kg) to low-dose cyclosporine (5 mg/kg) demonstrated a significant potentiating immunosuppressive effect, and the addition of high-dose sirolimus (2.0 mg/kg) to low-dose cyclosporine (5.0 mg/kg) demonstrated an even greater effect, with rejection scores better than those obtained with high-dose cyclosporine monotherapy and similar to those obtained with isografts. CONCLUSIONS: This study demonstrates that low-dose sirolimus has a cyclosporine-sparing effect and that a higher dose of sirolimus in combination with cyclosporine strongly protects lung allografts from acute cellular rejection. These results suggest that sirolimus may be indicated as an adjunct to current cyclosporine-based immunosuppressive regimens in clinical lung transplantation.

A comparison of the new preservation solution Celsior to Euro-Collins and University of Wisconsin solutions in lung reperfusion injury.

BACKGROUND: The lung is particularly susceptible to reperfusion injury, both experimentally and clinically after transplantation. The extracellular-type preservation solution Celsior, which has been predominantly studied in cardiac preservation, has components designed to prevent cell swelling, free radical injury, energy depletion, and calcium overload. Using an isolated blood-perfused rat lung model, we investigated whether Celsior would decrease preservation injury and improve lung function after cold ischemic storage and reperfusion compared to Euro-Collins (EC) and University of Wisconsin (UW) solutions. METHODS: Lewis rat lungs were isolated, flushed with the respective cold preservation solution, and then stored at 4 degrees C for 6 or 12 hr. After ischemic storage, the lung block was suspended from a force transducer, ventilated with 100% O2, and reperfused for 90 min with fresh blood via a cannula in the pulmonary artery. Lung compliance, alveolar-arterial oxygen difference, and outflow oxygen tension were all measured. The capillary filtration coefficient (Kf), a sensitive measure of changes in microvascular permeability, was determined. RESULTS: For 6 hr of cold storage, lungs stored in Celsior had lower Kf values than those stored in EC, indicating decreased microvascular permeability. No other significant differences were noted between Celsior and EC or UW. For 12 hr of cold storage, Celsior provided increased oxygenation, decreased alveolar-arterial O2 differences, increased compliance, and decreased Kf values as compared to both EC and UW. CONCLUSIONS: Celsior provides better lung preservation than EC or UW as demonstrated by increased oxygenation, decreased capillary permeability, and improved lung compliance, particularly at 12-hr storage times. These results are highly relevant, inasmuch as EC and UW are the most common clinically used lung preservation solutions. Further studies of Celsior in experimental and clinical lung transplantation, as well as in other solid organs, are indicated.

Photopheresis for the prevention of rejection in cardiac transplantation. Photopheresis Transplantation Study Group.

BACKGROUND: Photopheresis is an immunoregulatory technique in which lymphocytes are reinfused after exposure to a photoactive compound (methoxsalen) and ultraviolet A light. We performed a preliminary study to assess the safety and efficacy of photopheresis in the prevention of acute rejection of cardiac allografts. METHODS: A total of 60 consecutive eligible recipients of primary cardiac transplants were randomly assigned to standard triple-drug immunosuppressive therapy (cyclosporine, azathioprine, and prednisone) alone or in conjunction with photopheresis. The photopheresis group received a total of 24 photopheresis treatments, each pair of treatments given on two consecutive days, during the first six months after transplantation. The regimen for maintenance immunosuppression, the definition and treatment of rejection episodes, the use of prophylactic antibiotics, and the schedule for cardiac biopsies were standardized among all 12 study centers. All the cardiac-biopsy samples were graded in a blinded manner at a central pathology laboratory. Plasma from the subgroup of 34 patients (57 percent) who were enrolled at the nine U.S. centers was analyzed by polymerase-chain-reaction amplification for cytomegalovirus DNA. RESULTS: After six months of follow-up, the mean (+/-SD) number of episodes of acute rejection per patient was 1.44+/-1.0 in the standard-therapy group, as compared with 0.91+/-1.0 in the photopheresis group (P=0.04). Significantly more patients in the photopheresis group had one rejection episode or none (27 of 33) than in the standard-therapy group (14 of 27), and significantly fewer patients in the photopheresis group had two or more rejection episodes (6 of 33) than in the standard-therapy group (13 of 27, P=0.02). There was no significant difference in the time to a first episode of rejection, the incidence of rejection associated with hemodynamic compromise, or survival at 6 and 12 months. Although there were no significant differences in the rates or types of infection, cytomegalovirus DNA was detected significantly less frequently in the photopheresis group than in the standard-therapy group (P=0.04). CONCLUSIONS: In this pilot study, the addition of photopheresis to triple-drug immunosuppressive therapy significantly decreased the risk of cardiac rejection without increasing the incidence of infection.