Investigation of an outbreak of Salmonella enteritidis gastroenteritis associated with consumption of eggs in a restaurant chain in Maryland

Salmonella enteritidis ser. enteritidis was isolated from patrons and employees of three restaurants in a restaurant chain in Maryland during August and September 1985. Isolates from all three restaurants had identical plasmid profiles; this profile was present in 13 of 40 randomly selected S. enteritidis isolates received by the Maryland state health department laboratory during a comparable time period. The outbreak in one restaurant resulted in at least 71 illnesses, with 17 persons known to have been hospitalized. Scrambled eggs served on a "breakfast bar" were implicated as the vehicle of transmission in this restaurant, with eggs a possible vehicle in another of the three restaurants. The data point out the risks associated with improper handling of eggs in food service establishments, provide further evidence for the observed association between S. enteritidis and eggs in the northeastern United States, and demonstrate the utility of plasmid analysis in investigation of outbreaks involving common Salmonella serotypes.     

Effectiveness of neonatal transport in New York city in neonates less than 2500 grams—A population study

In the past two decades, there has been a gradual trend to regionalization of perinatal care, categorization of hospitals and transport services for neonatal health care. The literature alludes to both beneficial and deleterious effects of neonatal transport (T) but no controls such as a matched nontransport (NT) population have been utilized to date.The major goal of this study was to evaluate the effect of neonatal transport from Level I and II high risk 2500 gm. neonates (born in NYC in one calendar year, 1979) compared to a cohort nontransported population matched for hospital of birth, weight, race, sex and risk. All transported 2500 gm. from Level I and II (n=328) were studied and a stratified random sample of the nontransported (NT) infants 2500 gm. from these same hospitals (n=2042) was used for comparison. The principle outcome variable was survival. The major conclusion of this study is that in Level I and II hospitals the transport group had a significantly increased survival in infants who were sick (Apgar <6) compared to cohorted nontransported controls. Interhospital differences in survival were noted among Level I and II but not seen in the subdivisions of (A) and (B) hospitals.Angelo Ferrara, M.D., Ph.D., is Professor, Pediatrics, NYU Medical Center, New York, N.Y.: Melvin Schwartz, M.D., was Research Professor, Environmental Medicine, NYU Medical Center, New York, N.Y.; Helen Page, R.N., M.P.A., is Quality Assurance Reviewer, Manhattan Eye, Ear, Throat Hospital, New York, N.Y.: Morton Israel, M.A., is Research Scientist, Health Resources Administration, City of N. Y., New York, N.Y.; Yucel Atakent, M.D., M.S., is Clinical Associate Professor, NYU Medical Center, New York, N.Y.; C.E. Smith, Ph.D., is President, Health Policy Analysis & Accountability Network, Inc. (HPAAN), Edgewood, New Mexico; Leon Landovitz, Ph.D., is Vice President, Management Information Systems, Healthways System Inc., Islin, N.J.Supported by NCHSR Grant #5-R018-HSO3832     

Comparative uptake and retention of adriamycin andN-benzyladriamycin-14-valerate in human CEM leukemic lymphocyte cell cultures

Summary N-Benzyladriamycin-14-valerate (AD 198) is a new lipophilic adriamycin (ADR) analogue that shows marked therapeutic superiority to ADR in murine tumor model systems yet differs mechanistically from ADR in a number of ways. Among its other properties, AD 198 produces a delayed but profound effect on cell-cycle progression and a pattern of continuing DNA damage in cultured cells briefly exposed to the drug. Using radiolabeled drug forms and radioassays combined with HPLC separation and fluorimetric detection techniques, aspects of drug accumulation, biotransformation, and retention in cultured human CEM leukemic lymphocytes were studied, in part to determine a possible pharmacologic basis for the latent effects seen with this drug. In addition, the cellular pharmacology of AD 198 and ADR were comparatively examined under identical experimental conditions. When CEM cells were incubated with drug at equi-growth inhibitory/minimally cytotoxic concentrations (AD 198, 1.0 M; ADR, 0.1 M), a number of differences were apparent. Under conditions of continuous 24-h drug exposure, a slow cellular accumulation and equilibration was observed with ADR (cell: medium equilibrium, 1:11 after 4–6 h), whereas the uptake of AD 198 was rapid and extensive (cell: medium equilibrium, 3:1 within 30 min). In drug-retention studies, when cells were pretreated at the same drug concentrations as before (AD 198 for 1 h; ADR for 4 h) and then transferred to drug-free media, both compounds re-equilibrated their intracellular drug content with the fresh media, losing about 50% of their respective anthracycline levels. Liquid chromatographic analysis of ADR-treated cultures under both sets of conditions showed the parent drug to be the only intracellular anthracycline species, whereas analysis of AD 198-treated cultures revealed two fluorescent signals corresponding to the parent drug and its 14-deesterified biotransformation product,N-benzyladriamycin (AD 288). Levels of AD 288 rose from 2% of the total intracellular anthracycline content immediately on drug admixture to 61% following 24 h continuous drug exposure and to 69% at 24 h in cells exposed to drug for 1 h and then continued in drug-free media for 24 h. At all times, the balance of the intracellular anthracycline fluorescence was attributable to the parent drug; no ADR was detectable in AD 198-treated cells by either fluorescence detection or radioassay. Thus, AD 198 is not a prodrug form of ADR, and the in vitro effects of this agent, including the latent effects on cell-cycle inhibition and DNA damage seen in cells following short-term drug exposure, can be explained on the basis of the high levels of active parent drug and biotransformation product that accumulate and persist in the cells.Abbreviations ADR adriamycin (doxorubicin) - AD 198 N-benzyladriamycin-14-valerate - AD 288 N-benzyladriamycin - AD 32 N-trifluoroacetyladriamycin-14-valerate - AD 143 N-trifluoroacetyladriamycin-14-0-hemiadipate - AD 41 N-trifluoroacetyladriamycin - [¹⁴C]-AD 198 [benzyl]--methylene-¹⁴C]-N-benzyladriamycin-14-valerate - [¹⁴C]-ADR [14-¹⁴C]-adriamycin - HPLC high-performance liquid chromatography - TLC thin-layer chromatography - DMSO dimethylsulfoxide - S-MEM Eagle's minimum essential medium for suspension culture - PBS phosphate-buffered saline (pH 7.0)     

Osteogenic differentiation of human bone marrow stromal cells on partially demineralized bone scaffolds in vitro

Tissue engineering has been used to enhance the utility of biomaterials for clinical bone repair by the incorporation of an osteogenic cell source into a scaffold followed by the in vitro promotion of osteogenic differentiation before host implantation. In this study, three-dimensional, partially demineralized bone scaffolds were investigated for their ability to support osteogenic differentiation of human bone marrow stromal cells (BMSCs) in vitro. Dynamic cell seeding resulted in homogeneous cell attachment and infiltration within the matrix and produced significantly higher seeding efficiencies when compared with a conventional static seeding method. Dynamically seeded scaffolds were cultured for 7 and 14 days in the presence of dexamethasone and evaluated on biochemical, molecular, and morphological levels for osteogenic differentiation. Significant elevation in alkaline phosphatase activity was observed versus controls over the 14-day culture, with a transient peak indicative of early mineralization on day 7. On the basis of RT-PCR, dexamethasone-treated samples showed elevations in alkaline phosphatase and osteocalcin expression levels at 7 and 14 days over nontreated controls, while bone sialoprotein was produced only in the presence of dexamethasone at 14 days. Scanning electron microscopy evaluation of dexamethasone-treated samples at 14 days revealed primarily cuboidal cells indicative of mature osteoblasts, in contrast to nontreated controls displaying a majority of cells with a fibroblastic cell morphology. These results demonstrate that partially demineralized bone can be successfully used with human BMSCs to support osteogenic differentiation in vitro. This osseous biomaterial may offer new potential benefits as a tool for clinical bone replacement.     

An intracellular antigen that reacts with MO2, a monoclonal antibody to CD14, is expressed by human lymphocytes

CD14, a lipopolysaccharide (LPS) receptor, is present on the surface membrane of phagocytic leukocytes; it is also present in a soluble form in serum. Recently published results confer to this molecule novel functions that are linked to T-cell activation and to apoptosis. We report here that we have defined and characterized a novel lymphocyte population in human peripheral blood, a population that expresses an intracellular antigen detectable with MO2, a monoclonal antibody directed against the human CD14 molecule. This population is composed primarily of CD8-positive T-cells. We found surprisingly that this novel MO2-positive population of lymphocytes was greatly enhanced in asymptomatic, untreated HIV-positive individuals.     

Performance of hydroxyapatite bone repair scaffolds created via three-dimensional fabrication techniques

The current study analyzes the in vivo performance of porous sintered hydroxyapatite (HA) bone repair scaffolds fabricated using the TheriForm solid freeform fabrication process. Porous HA scaffolds with engineered macroscopic channels had a significantly higher percentage of new bone area compared with porous HA scaffolds without channels in a rabbit calvarial defect model at an 8-week time point. An unexpected finding was the unusually large amount of new bone within the base material structure, which contained pores less than 20 microm in size. Compared with composite scaffolds of 80% polylactic-co-glycolic acid and 20% beta-tricalcium phosphate with the same macroscopic architecture as evaluated in a previous study, the porous HA scaffolds with channels had a significantly higher percentage of new bone area. Therefore, the current study indicates that scaffold geometry, as determined by the fabrication process, can enhance the ability of a ceramic material to accelerate healing of calvarial defects.     

Viral abrogation of lymphocyte mitogenesis: induction of a soluble factor inhibitory to cellular proliferation.

PHA and Con A-driven mitogenesis of mouse C3H lymphocytes can be inhibited by co-incubation with a variety of different virus particles. These effects appear independent of infection, and can be obtained using UV-inactivated virus. Viruses may be added to spleen cell cultures as late as 46 h after co-incubation with mitogen, and still achieve significant inhibition of proliferative responsiveness. The described inhibition is apparently mediated, in part at least, by a soluble factor which is induced in splenic cultures following interaction with virus particles. This factor is apparently a product of macrophages. It does not posess interferon activity, but does have the ability to inhibit lectin- and alloantigen-driven mitogenesis, as measured in fresh cultures of splenic lymphocytes and in the mixed lymphocyte culture (MLC) reaction, respectively. Moreover, addition of virus to splenic cultures can apparently activate suppressor lymphocytes with the ability to inhibit proliferative responsiveness of fresh lymphocyte suspensions in the presence of Con A.     

Intrathoracic pressure fluctuations move blood during CPR: Comparison of hemodynamic data with predictions from a mathematical model

Whether blood flow during cardiopulmonary resuscitation (CPR) results from intrathoracic pressure fluctuations or direct cardiac compression remains controversial. We developed a mathematical model that predicts that blood flow due to intrathoracic pressure fluctuations should be insensitive to compression rate over a wide range but dependent on the applied force and compression duration. If direct compression of the heart plays a major role, however, the model predicts that flow should be dependent on compression rate and force, but above a threshold, insensitive to compression duration. These differences in hemodynamics produced by changes in rate and duration form a basis for determining whether blood flow during CPR results from intrathoracic pressure fluctuations or from direct cardiac compression. The model was validated for direct cardiac compression by studying the hemodynamics of cyclic cardiac deformation following thoracotomy in four anesthetized, 21–32-kg dogs. As predicted by the model, there was no change in myocardial or cerebral perfusion pressures when the duration of compression was increased from 15% to 45% of the cycle at a constant rate of 60/min. There was, however, a significant increase in perfusion pressures when rate was increased from 60 to 150/min at a constant duration of 45%. The model was validated for intrathoracic pressure changes by studying the hemodynamics produced by a thoracic vest (vest CPR) in eight dogs. The vest contained a bladder that was inflated and deflated. Vest CPR changed intrathoracic pressure without direct cardiac compression, since sternal displacement was <0.8 cm. As predicted by the model and opposite to direct cardiac compression, there was no change in perfusion pressures when the rate was increased from 60 to 150/min at a constant duration of 45% of the cycle. Manual CPR was then studied in eight dogs. There was no surgical manipulation of the chest. Myocardial and cerebral blood flows were determined with radioactive microspheres and behaved as predicted from the model of intrathoracic pressure, not direct cardiac compression. At nearly constant peak sternal force (378–426 N), flow was significantly increased when the duration of compression was increased from short (13%–19% of the cycle) to long (40%–47%), at a rate of 60/min. Flow was unchanged, however, for an increase in rate from 60 to 150/min at constant compression duration. In addition, myocardial and cerebral flow correlated with their respective perfusion pressures. Thus vital organ perfusion pressures and flow for manual external chest compression are dependent on the duration of compression, but not on rates of compression of 60 and 150/min. These data are of course similar to those produced by vest CPR, where intrathoracic pressure is manipulated without sternal displacement, and to those predicted for movement of blood by intrathoracic pressure changes. These data are, however, opposite to those produced by cardiac deformation and to those predicted for movement blood by direct cardiac compression. We conclude that intrathoracic pressure fluctuations generate blood flow during manual CPR.     

HLA alleles and haplotypes among the Lakota Sioux: report of the ASHI minority workshops, part III

Human leukocyte antigen (HLA) class I and II alleles were defined for 302 Lakota Sioux American Indians as part of the American Society for Histocompatibility and Immunogenetics coordinated studies on minority populations. The study group was comprised of adult volunteers from the Cheyenne River and Ogala Sioux tribes residing, respectively, on the Cheyenne River and Pine Ridge Reservations in South Dakota. Of the participants, 263 (87%) claimed full American Indian ancestry through both maternal and paternal grandparents. The study group included 25 nuclear families that were informative for genotyping. HLA phenotypes from 202 adults with no other known first-degree relative included in the study were used for calculation of allele and haplotype frequencies by maximum likelihood estimation. HLA-A, -B, and -Cw alleles were found to be in Hardy Weinberg equilibrium. Deviation from equilibrium was observed for DRB1 alleles (p=0.01), but could be attributed to the sample size and the occurrence of some genotypes with low expected frequencies. Polymorphism among the Sioux was limited with four to seven alleles comprising >80% of those observed at each locus. Several alleles were found at high frequency (0.05-0.30) among the Sioux that are also prevalent in other Native Americans and Alaska Natives, including: A*2402, *3101, and *0206; B*3501,*3901, *5101, and *2705; Cw*0702, *0404, and *03041; DRB1*0407, *0404, *1402, and *16021; and DQB1*0301, *0302, and *0402. DRB1*0811, which has been only previously described in Navajo and Tlingit Indians, was found to occur at a frequency of 0.119 among the Sioux. Two new alleles were defined among the Sioux: Cw*0204 and DRB1*040703, which were found in two and four individuals, respectively. In the haplotype analyses, significant linkage disequilibrium (p<0.00001) was seen in all pairwise comparisons of loci and numerous two and three locus haplotypes were found to have strong, positive linkage disequilibrium values. The two most common extended haplotypes among the Sioux, determined by maximum likelihood estimation and genotyping were: A*31012, B*3501, Cw*0404, DRB1*0407; and A*24021, B*3501, Cw*0404, DRB1*0404.