Factors influencing the incidence and prevalence of food allergy.

Food allergy is an increasing problem in Europe and elsewhere and severe reactions to food are also becoming more common. As food allergy is usually associated with other forms of allergic sensitisation it is likely that many risk factors are common to all forms of allergy. However the potential severity of the disease and the specific public heath measures required for food allergy make it important to identify the specific risk factors for this condition. Food allergy is unusual in that it often manifests itself very early in life and commonly remits with the development of tolerance. Hypotheses that explain the distribution of food allergy include specific genetic polymorphisms, the nature of the allergens involved and the unique exposure to large quantities of allergen through the gut. Progress has been made in developing more specific and testable hypotheses but the evidence for any of these is still only preliminary. Further collaborative research is required to develop an appropriate public health response to this growing problem.

Probiotic research in Australia, New Zealand and the Asia-Pacific region.

Although the epicentres of probiotic research in the past decade have been Japan and Europe, researchers in the Asia-Pacific region have actively contributed to the growing understanding of the intestinal microbial ecosystem, and interactions between gut bacteria, diet and health of the human host. A number of new probiotic strains have been developed in the region that have been demonstrated to have beneficial impacts on health in animal and human trials, including improved protection against intestinal pathogens and modulation of the immune system. Probiotics targeted to animals, including aquaculture, feature heavily in many Asian countries. Developments in probiotic technologies have included microencapsulation techniques, antimicrobial production in fermented meats, and synbiotic combinations. In particular, the impact of resistant starch on the intestinal environment and fermentation by intestinal bacteria has been intensively studied and new probiotic strains selected specifically for synbiotic combinations with resistant starch. This paper provides an overview of probiotic research within Australia, New Zealand and a number of Asian countries, and lists scientists in the Asia-Pacific region involved in various aspects of probiotic research and development.

Synthesis and utilisation of folate by yoghurt starter cultures and probiotic bacteria.

Thirty-two bacterial isolates from species commonly used in yoghurts and fermented milks were examined for their ability to synthesise or utilise folate during fermentation of skim milk. The organisms examined included the traditional yoghurt starter cultures, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, and probiotic lactobacilli, bifidobacteria, and Enterococcus faecium. Folate was synthesised by S. thermophilus, bifidobacteria, and E. faecium. S. thermophilus was the dominant producer, elevating folate levels in skim milk from 11.5 ng g(-1) to between 40 and 50 ng g(-1). Generally, lactobacilli depleted the available folate in the skim milk. Fermentations with mixed cultures showed that folate production and utilisation by the cultures was additive. Fermentations using a combination of Bifidobacterium animalis and S. thermophilus resulted in a six-fold increase in folate concentration. Although increased folate levels in yoghurts and fermented milks are possible through judicious selection of inoculum species, the folate levels remain relatively low in terms of recommended daily allowance.

Gut bacteria and health foods--the European perspective.

Probiotics, prebiotics, and synbiotics aimed at improving intestinal health currently represent the largest segment of the functional foods market in Europe, Japan and Australia. Evidence continues to emerge demonstrating that these ingredients have the potential to improve human health in specific intestinal disorders. The European Commission, through its 5th Framework Programme, is presently focusing on a substantial effort in the science of the intestinal microbiota, its interaction with its host and methods to manipulate its composition and activity for the improvement of human health and well being. Eight multicentre and multidisciplinary research projects now cover a range of topics required for the development of efficacious probiotic foods, from understanding probiotic mechanisms at a molecular level; developing technologies to ensure delivery of stable products; and demonstrating safety and efficacy of specific probiotics in defined treatment targets. This concerted research effort promises to provide us with an enhanced understanding of the human intestinal microbiota's role in health and disease, and new approaches and products to tackle a variety of intestinal problems.

Purification of food-grade oligosaccharides using immobilised cells of Zymomonas mobilis.

Immobilised cells of the bacterium Zymomonas mobilis were used to remove glucose, fructose, and sucrose from food-grade oligosaccharide mixtures. Unpurified fructo-, malto-, isomalto-, gentio-, and inulinoligosaccharides, containing total carbohydrate concentrations of 300 g l(-1), were added to immobilised cells, in 100 ml batch reactors. No pH control or nutrient additions were required. Contaminating glucose, fructose, and sucrose within the mixtures was completely fermented within 12 h. The fermentation end products were ethanol and carbon dioxide. A minor amount of sorbitol was also produced as a fermentation by-product in the inulin-oligosaccharide mixture. No degradation of the oligosaccharides in the mixtures was observed.

Cross correlation of the cosmic microwave background with radio sources: constraints on an accelerating universe.

We present a new limit on the cosmological constant based on the absence of correlations between the cosmic microwave background (CMB) and the distribution of distant radio sources. In cosmological constant, cold dark matter ( LambdaCDM) models, such correlations should have been produced via the integrated Sachs-Wolfe effect, assuming that radio sources trace the local ( z approximately 1) matter density. We find no evidence of correlations and obtain a 95% C.L. upper limit on the cosmological constant of Omega(Lambda)< or =0.74. If 0.6

Adhesion of bifidobacteria to granular starch and its implications in probiotic technologies.

Adhesion of 19 Bifidobacterium strains to native maize, potato, oat, and barley starch granules was examined to investigate links between adhesion and substrate utilization and to determine if adhesion to starch could be exploited in probiotic food technologies. Starch adhesion was not characteristic of all the bifidobacteria tested. Adherent bacteria bound similarly to the different types of starch, and the binding capacity of the starch (number of bacteria per gram) correlated to the surface area of the granules. Highly adherent strains were able to hydrolyze the granular starches, but not all amylolytic strains were adherent, indicating that starch adhesion is not a prerequisite for efficient substrate utilization for all bifidobacteria. Adhesion was mediated by a cell surface protein(s). For the model organisms tested (Bifidobacterium adolescentis VTT E-001561 and Bifidobacterium pseudolongum ATCC 25526), adhesion appeared to be specific for alpha-1,4-linked glucose sugars, since adhesion was inhibited by maltose, maltodextrin, amylose, and soluble starch but not by trehalose, cellobiose, or lactose. In an in vitro gastric model, adhesion was inhibited both by the action of protease and at pH values of < or =3. Adhesion was not affected by bile, but the binding capacity of the starch was reduced by exposure to pancreatin. It may be possible to exploit adhesion of probiotic bifidobacteria to starch granules in microencapsulation technology and for synbiotic food applications.

Surveying graduates of one school to determine regional workforce demand.

PURPOSE: To study the demand for physician graduates from one school in one region of the country. The use of demand as a measure of potential regional variation should be of interest to medical educators and policymakers. METHOD: All residency graduates of the University of Washington School of Medicine between 1975 and 1995 (n = 3,824) were surveyed about their ability to gain employment in a timely manner and whether they were recruiting physicians for their practices. RESULTS: The response rate was 50.29%. A non-responder survey was done using a subsample (n = 200), with a 28% return. Over 95% of the graduates had found employment in their desired specialties and locations within two years of finishing their residencies. This was the same for graduates over all years. Approximately 30% of all practices of respondents within the Northwest region were recruiting for new physicians (26% of specialty practices and 34% of generalist practices were recruiting). There was no difference between recruitment in the urban and rural practices or between respondents to the initial survey and those responding to the follow up. CONCLUSIONS: Despite a significant oversupply of specialist physicians and at least a sufficient supply of generalist physicians nationally, there appears to be a strong demand for both specialists and generalists in the Northwest region of the country. This raises questions concerning the use of national averages to inform the education policies in specific regions of the country. More validated measures of demand are needed for future studies.

Selection of a Bifidobacterium strain to complement resistant starch in a synbiotic yoghurt.

AIMS: To employ an in vitro screening regime to select a probiotic Bifidobacterium strain to complement resistant starch (Hi-maizetrade mark) in a synbiotic yoghurt. METHODS AND RESULTS: Of 40 Bifidobacterium isolates examined, only B. lactis Laftitrade mark B94 possessed all of the required characteristics. This isolate hydrolysed Hi-maizetrade mark, survived well in conditions simulating passage through the gastrointestinal tract and possessed technological properties suitable for yoghurt manufacture. It grew well at temperatures up to 45 degrees C, and grew to a high cell yield in an industrial growth medium. In addition to resistant starch, the organism was able to utilize a range of prebiotics including inulin, and fructo-, galacto-, soybean- and xylo-oligosaccharides. Pulse field gel electrophoresis of restriction enzyme cut chromosomal DNA revealed that B. lactis Laftitrade mark B94 was very closely related to the B. lactis Type Strain (DSM 10140), and to the commercial strains B. lactis Bb-12 and B. lactis DS 920. However, B. lactis Laftitrade mark B94 was the only one of these isolates that could hydrolyse Hi-maizetrade mark. This phenotypic difference did not appear to be due to the presence of plasmid encoded amylase. Bifidobacterium lactis Laftitrade mark B94 survived without substantial loss of viability in synbiotic yoghurt containing Hi-maizetrade mark during storage at 4 degrees C for six weeks. CONCLUSION: Bifidobacterium lactis Laftitrade mark B94 is a promising new yoghurt culture that warrants further investigation to assess its probiotic potential. SIGNIFICANCE AND IMPACT OF THE STUDY: In vitro screening procedures can be used to integrate complementary probiotic and prebiotic ingredients for new synbiotic functional food products.

Quality assurance criteria for probiotic bacteria.

Acid and bile stability and intestinal mucosal adhesion properties are among the criteria used to select probiotic microbes. The quality control of probiotic cultures in foods traditionally has relied solely on tests to ensure that an adequate number of viable bacteria are present in the products throughout their shelf lives. Viability is an important factor, but not the only criterion for quality assurance. To be effective, probiotic strains must retain the functional health characteristics for which they were originally selected. Such characteristics include the ability to survive transit through the stomach and small intestine and to colonize the human gastrointestinal tract. In vitro test protocols can be readily adopted to examine the maintenance of a strain's ability to tolerate acidic conditions, survive and grow in the presence of bile, and metabolize selective substrates. Molecular techniques are also available to examine strain stability. Adhesion characterization may be an important quality-control method for assessing gut barrier effects. Adhesion has been related to shortening the duration of diarrhea, immunogenic effects, competitive exclusion, and other health effects. Adhesion properties should be carefully monitored, including adhesion to intestinal cells (eg, Caco-2) and human intestinal mucus. This article outlines the types of in vitro testing that can be used to ensure quality control of functional probiotic strains.

The effects of payback and loan repayment programs on medical student career plans.

Many states have considered implementing payback programs on state-subsidized medical education to increase the rate of graduates returning to those states to practice. An alternative is for states to offer and expand loan repayment programs to entice medical school graduates from rural states to return to their home states. The goal of this study is to determine and contrast the impact these two types of programs might have on medical school choice and students' intentions to return to their home states. Two hundred twenty-nine medical students were surveyed (response rate 80 percent). The questionnaire collected background information on the students and addressed the possible impact of payback and loan repayment policy proposals on student plans. Forty-seven percent of students reported that they would attend a different medical school if a required payback program were in place. Students who were more competitive at the time of admission to medical school were significantly more likely to say they would attend another medical school than were less competitive students. In contrast, 48 percent of students reported that they would be more likely to return to their home states if expanded loan repayment programs were available for service in areas of need. The findings suggest that payback programs may dissuade more competitive students from entering medical schools with such requirements, compromising the pool of students most likely to return to rural areas. Conversely, medical students appear willing to consider loan repayment programs upon completion of their training.

The Balanced Budget Act of 1997 and rural training supported by Medicare graduate medical education funds.

The Balanced Budget Act of 1997 promised a number of changes in medical education to benefit rural communities. The changes suggested that physician training would be more available in rural communities, programs training physicians for work in rural communities would be better supported, and residency programs would be allowed to be separate from hospitals. The regulations developed by the Health Care Financing Administration to implement the act are reviewed in the context of these expectations. Limitations in the regulations indicate that rural communities will see little benefit from this legislation. This article is a commentary on the expectations and reality of the effects of the Balanced Budget Act of 1997 on rural training supported by Medicare.

In vitro adhesion and platelet aggregation properties of bacteremia-associated lactobacilli.

Eight bacteremia-associated Lactobacillus strains were evaluated in vitro for the ability to adhere to human intestinal mucosa and to aggregate platelets. Adherence varied significantly among the strains, and platelet aggregation was induced by three strains. In conclusion, strong binding ability does not appear to be a prerequisite for the involvement of lactobacilli in bacteremia or to their ability to aggregate platelets.

The changing landscape of health care financing and delivery: how are rural communities and providers responding?

Rural communities have not kept pace with the recent dramatic changes in health care financing and organization. However, the Medicare provisions in the Balanced Budget Act of 1997 will require rural providers to participate in the new systems. Case studies revealed the degree of readiness for change in six rural communities and charted their progress along a continuum, as reflected in three sets of activities: the development of networking; the creation of new strategies for managing patient care; and the adoption of new methods for contracting with health insurers. Some communities had constructed highly integrated systems, whereas others were just beginning to change their billing practices; a few were signing contracts for capitated care, in contrast to those that were resisting discounts in current fee structures. These six rural areas still have considerable ground to cover before their health care organization and financing reach the levels achieved by urban communities.

Proto-oncogene Sno expression, alternative isoforms and immediate early serum response.

The mouse Sno gene, a Ski proto-oncogene homolog, expresses two isoforms, SnoN and SnoN2 (also called sno -dE3), which differ from each other in a location downstream from the site of alternative splicing previously described in the human SNO gene. SnoN2 is missing a 138 nt coding segment present in mouse SnoN and human SNON . We have cloned and sequenced the human ortholog of mouse SnoN2 , the existence of which was predicted from conservation of the alternative splice donor site that produces the SnoN2 isoform. Mouse SnoN2 and SnoN are expressed throughout embryonic development, in neonatal muscle and in many adult tissues. SnoN2 is the major species in most tissues, but SnoN and SnoN2 are expressed at approximately equal levels in brain. In human tissues, SNON2 is the less abundantly expressed isoform. Expression of mouse SnoN and SnoN2 mRNAs is induced with immediate early kinetics upon serum stimulation of quiescent fibroblasts, even in the presence of the protein synthesis inhibitor cycloheximide, while Ski is not. Interestingly, although both isoforms of Sno are induced, SnoN2 induction is much higher than SnoN . These data are consistent with a role for Sno in the response to proliferation stimuli.

Cytokine-facilitated transduction leads to low-level engraftment in nonablated hosts.

Using a murine bone marrow transplantation model, we evaluated the long-term engraftment of retrovirally transduced bone marrow cells in nonmyeloablated hosts. Male bone marrow was stimulated in a cocktail of interleukin-3 (IL-3), IL-6, IL-11, and stem cell factor (SCF) for 48 hours, then cocultured on the retroviral producer line MDR18.1 for an additional 24 hours. Functional transduction of hematopoietic progenitors was detected in vitro by reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of multiple drug resistance 1 (MDR1) mRNA from high proliferative potential-colony forming cell (HPP-CFC) colonies. After retroviral transduction, male bone marrow cells were injected into nonablated female mice. Transplant recipients received three TAXOL (Bristol-Myers, Princeton, NJ) injections (10 mg/kg) over a 14-month period. Transplant recipient tissues were analyzed by Southern blot and fluorescence in situ hybridization for Y-chromosome-specific sequences and showed donor cell engraftment of approximately 9%. However, polymerase chain reaction amplification of DNAs from bone marrow, spleen, and peripheral blood showed no evidence of the transduced MDR1 gene. RT-PCR analysis of total bone marrow RNA showed that transcripts from the MDR1 gene were present in a fraction of the engrafted donor cells. These data show functional transfer of the MDR1 gene into nonmyeloablated murine hosts. However, the high rates of in vitro transduction into HPP-CFC, coupled with the low in vivo engraftment rate of donor cells containing the MDR1 gene, suggest that the majority of stem cells that incorporated the retroviral construct did not stably engraft in the host. Based on additional studies that indicate that ex vivo culture of bone marrow induces an engraftment defect concomitantly with progression of cells through S phase, we propose that the cell cycle transit required for proviral integration reduces or impairs the ability of transduced cells to stably engraft.

Stem cell transplantation in the normal nonmyeloablated host: relationship between cell dose, schedule, and engraftment.

In previous studies we have shown high rates of stable engraftment when 40 million male BALB/c cells were infused intravenously daily for 5 days (a total of 200 million cells) to normal nonmyeloablated female hosts. The present studies evaluate engraftment of male BALB/c bone marrow cells in female host marrow, spleen, and thymus 20-25 weeks after transplantation using varying cell dosages within a 5-day schedule. Engraftment in recipient mice was assessed by detection of male specific sequence in recipient DNA from each organ. When 40 million cells were given per daily injection for 1, 2, 3, 4, or 5 days, engraftment percentages in host marrow were 11 +/- 0.83, 20 +/- 2.0, 23 +/- 2.5, 32 +/- 6.3, and 39% +/- 5.7 (+/- standard error of mean), respectively, yielding engraftment percentages per million cells infused of 0.28, 0.25, 0.19, 0.20, and 0.20%, respectively. When levels of 2.5, 5, 10, 20, or 40 million cells were injected 5 times over a 5-day schedule into normal BALB/c female hosts, progressively increasing levels of engraftment from 3 +/- 0.6 to 39% +/- 5.7 were seen in host marrow. Highest levels of engraftment per million cells injected were obtained on days 1 and 2 of a 5-day schedule and with a level of 10 million cells given daily over 5 days. Engraftment profiles varied with spleen and thymus and percent engraftment was generally lower than for marrow. The present work indicates that regardless of cell level infused or number of infusions, rates of engraftment observed in marrow approached or exceeded the highest rates of engraftment estimated by theoretical calculations based on replacing host cells ("replacement model") or adding to host cells ("incremental model"). Engraftment in spleen and thymus was lower, but also at times approached or exceeded theoretical maxima. These data show extraordinary levels of engraftment in normal hosts, suggesting that rates in this competitive model are superior to those seen in irradiated hosts; alternatively, there may be selective repression of host stem cell proliferation and differentiation.