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PubMedDate not supplied

Microbiologic quality-control study for the purpose of extending the use of transfer sets on the automix 3 + 3 and micromix automated total nutrient admixture compounding pumps.

BACKGROUND: A quality-control study was undertaken by the departments of pharmacy and microbiology at St. Paul's Hospital (Vancouver, British Columbia, Canada) to evaluate the microbiologic safety of total nutrition admixtures (TNA) compounded by automated compounding pumps when the use of disposable transfer sets was extended from 1 day to 2 days. This study also evaluates the potential annual cost savings of this extended use. METHODS: Transfer sets and unused part containers of ingredients were left to sit overnight on the automated compounders after daily TNA manufacturing before a TNA sample was compounded for culturing. These TNA samples were cultured using a biphasic system consisting of a tryptic soy broth component and an agar slide component. Positive results were subcultured and isolates were identified by standard methods. Forty samples were collected and evaluated. RESULTS: Four bags grew Bacillus species, and 1 bag grew coagulase-negative staphylococci. The potential annual cost savings of this extended use was estimated to be approximately 35,000 Canadian dollars. CONCLUSIONS: The extended use of the disposable transfer sets cannot be instituted at the present time and should be reexamined when the cause(s) of the positive results are identified and corrected.

Bacillus↗
PubMedDate not supplied

Effect of amino acid solutions on total nutrient admixture stability.

The stability of total nutrient admixture (TNA) systems containing a soybean oil emulsion (Soyacal) has been reported with only one amino acid (AA) solution. This study was conducted to compare the physical stability of 10 TNA systems varied only by the AA solution used. All systems contained electrolytes, vitamins, trace elements, and heparin. The volume ratios of AA, dextrose 70% and lipid emulsion 20% were 1:1:1. Solutions were stored at 4 degrees C for 14 days and then held at ambient temperature for an additional 4 days. Each TNA was serially analyzed on days 0, 1, 3, 5, 7, 14, 15, 16, 17, and 18 for gross visual appearance, pH, osmolality, mean particle diameter, and particle size distribution. The AA solutions evaluated include: Travasol 8.5% and 10%; Aminosyn 8.5% and 10%, Aminosyn RF 5.2%; FreAmine III 8.5% and 10%; FreAmine HBC 6.9%; HepatAmine 8.0%; and NephrAmine 5.4%. The pH values of the Aminosyn solutions were lower than those of other products; however, the pH values of all TNA systems were greater than 5.7, which supported particle stability. The osmolality was not affected by the AA solutions. Based upon particle size distribution, 95% of all particles were less than 0.608 micron in diameter, with means ranging from 0.286 micron to 0.309 micron. The largest particle observed by light microscopy was 6.9 micron. These data indicate that TNA systems prepared with the 10 AA solutions and Soyacal 20% are physically stable.

Amino Acids↗
PubMedDate not supplied

Answering the fat emulsion contamination question: three in one admixture vs conventional total parenteral nutrition in a clinical setting.

Fat emulsions (FE) support microbial growth when inoculated in vitro; dextrose/amino acid solutions (D/AA) do not. Can FE be safely added to D/AA when delivered over 24 hrs? We attempted to answer this question by culturing both conventional (C) total parenteral nutrition (TPN), in which the FE and D/AA are given separately, and the 3-in-1 admixture TPN, in which all components are delivered in one bag. Two-hundred TPN fluid cultures were obtained serially by collecting 1 ml of fluid from the distal-most connection when the TPN was changed every 24 hrs. Quantiative and qualitative cultures were obtained. One hundred sixty-six (83%) were negative. Of the 34 (17%) positive cultures, 15 (17% of 88) were from the conventional system whereas 19 (17% of 112) were from the 3-in-1 system. Six clinically septic patients furnished 11 TPN fluid specimens which grew greater than 400 colonies/ml. Seven (8% of 88) of these were from the conventional system whereas four (3.6% of 112) were from the 3-in-1 system. All had distant sites of sepsis. The 23 remaining positive TPN fluid cultures grew less than 25 colonies/ml, with 20 growing Staphylococcus epidermidis. All of these patients were clinically well and there was no significant difference in the distribution of positive cultures between the conventional system (9%) and the 3-in-1 system (13%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Catheter obstruction: analysis of filter content of total nutrient admixture.

Catheter blockage in patients receiving long-term parenteral nutrition with fat-containing total nutrient admixture (TNA) is a relatively common complication. A study was carried out to characterize the material which is filtered out of the TNA and is a potential cause of catheter blockage. A total of 45 bags containing the same TNA solution were stored for 7 days at 4 degrees C. The stability of the solution in all the bags was then confirmed by light microscope and Coulter Counter, to determine the particle-size distribution, following which the solution was filtered through a 5-microns filter. Chemical analysis was then made to determine the amount of solid particles, fat and precipitates of Mg, Zn, Ca, Na, and K in the filter contents. Each bag was found to contain 7326 +/- 2681 solid particles as plasticizers and the main component of the filter contents was fat (99.4%) whereas electrolytes as precipitates constituted less than 0.5%. The amount of fat and electrolytes lost on the filter from the solution was negligible. Our analysis of the material trapped on the filter, which may block the catheter during long-term therapy, suggests the importance of filtration and of finding a means for dissolving the fat, the main component of the filter material.

Catheterization, Peripheral↗
PubMedDate not supplied

Histamine receptor antagonists and lipid stability in total nutrient admixtures.

Drug stability and compatibility studies should be performed for all medications added to total nutrient admixtures (TNAs) before administration to patients. The stability of TNA components will vary depending on product selection and final concentrations. This variability prohibits generalizing published study results generically to TNAs containing untested products or combinations. Histamine receptor antagonists (H2RAs) are commonly administered by continuous infusion via nutrient solutions. When the delivery vehicle is a TNA, comparative stability and compatibility studies performed under similar test conditions are lacking. The stability of marketed parenteral H2RAs and of the investigational H2RA, nizatidine was analyzed in TNA solutions containing either Liposyn II or Intralipid at differing concentrations. All H2RAs remained at more than 90% of initial concentration at 24 hours. After 48 hours, only ranitidine concentrations fell to less than 90% in all study solutions. Each TNA containing an H2RA was within pH stability ranges for lipid products, and no change in particle size was detected during the 48-hour period. This is the first report determining H2RA compatibility and stability in TNA solutions with both 3% and 5% Intralipid and Liposyn II and using similar methodology for all standard H2RA concentrations. Results suggest that these drugs are stable for 24 hours in TNAs containing either lipid product. Beyond this time, administration of ranitidine may be unreliable because of poor stability under the conditions tested.

Drug Stability↗
PubMedDate not supplied

Fatal microvascular pulmonary emboli from precipitation of a total nutrient admixture solution.

BACKGROUND: Paroxysmal respiratory failure and death occurred in two young adult females with pelvic infections. Autopsy revealed an amorphous material containing calcium obstructing the pulmonary microvasculature of each patient. Both patients received an identical total nutrient admixture (TNA) solution before their deaths. METHODS: Infusion of TNA into an animal model was undertaken in an effort to reproduce the clinical effect. Laboratory investigation was also performed to isolate a precipitate and identify the factors contributing to precipitation. RESULTS: A nonvisible precipitate containing calcium, phosphorus, and organic material was isolated from the TNA solution. Infusion of the formulation into healthy pigs resulted in sudden death within 4 hours. Alteration of the amino acid component, mix sequence, agitation technique, and mixing container influenced precipitate formation. CONCLUSION: Pulmonary embolization of a precipitate containing calcium phosphate resulted in the death of two patients. The pH of the amino acid component, transient elevation of calcium and phosphorus concentrations during mixing, and the lack of agitation during automated preparation of the formulation were identified as the etiologic factors producing the fatal precipitate.

Adult↗
PubMed1999

Propofol-thiopentone admixture: recovery characteristics.

We have investigated, in a prospective double-blind study, recovery from anaesthesia induced by two admixtures of propofol and thiopentone and compared it with a third group of patients who received propofol and lignocaine. Ninety unpremedicated ASA 1 or 2 patients scheduled for elective gynaecological laparoscopy as a daycase procedure were randomly allocated to receive one of three different mixtures for induction of anaesthesia as part of a standardized anaesthetic: Group P50: propofol 1% 10 ml/thiopentone 2.5% 10 ml, Group P75: propofol 1% 15 ml/thiopentone 2.5% 5 ml, Group P100: propofol 1% 20 ml/lignocaine 1% 4 ml. Recovery from anaesthesia was assessed for up to four hours post-induction by critical flicker fusion threshold and best post-box toy completion time. Comparison was made with preoperative baseline performance. There was no significant difference in postoperative recovery between the three groups with either assessment but no group returned to their mean preoperative performance levels within the first four hours post-induction. Nor was there any difference between the groups with respect to postoperative analgesia or anti-emetic administration. Utilizing the most sensitive end-point, a sample of nearly 1000 patients in each group would be required to confirm the observed difference with a power of 0.8 based on the data from this study. In comparison with lignocaine, the addition of thiopentone to propofol does not delay recovery from anaesthesia and does not increase postoperative analgesic or anti-emetic requirements.

Adult↗
PubMed1982

Cytosine arabinoside stability in intravenous admixtures with sodium bicarbonate and in plastic syringes.

The increased use of high-dose cytarabine in the treatment of neoplasms prompted this study on the reconstituted stability of cytarabine in intravenous admixtures with sodium bicarbonate and in plastic syringes. The study of the effect of sodium bicarbonate was prompted by the frequent use of this agent in patients being treated with cytarabine as a means of achieving systemic alkalinization in order to manage hyperuricemia. The stability of reconstituted cytarabine in plastic syringes was measured to determine whether cytosine arabinoside could be reconstituted and stored prior to use. The results of this study indicate that sodium bicarbonate 50 mEq/L in the intravenous solution containing cytarabine has no effect on the chemical stability of cytarabine for at least one week at room temperature or in the refrigerator. Consequently sodium bicarbonate and cytarabine can be coadministered in one intravenous solution. The reconstituted stability of cytarabine at 20 mg/ml and 50 mg/ml is not affected by storage in plastic syringes.

Bicarbonates↗
PubMed1992

Compatibility of ceftazidime and aminophylline admixtures for different methods of intravenous infusion.

OBJECTIVE: Aminophylline and ceftazidime are sometimes used concurrently in patients with respiratory disorders. Parenteral aminophylline usually is administered as a constant infusion, and ceftazidime is given intermittently or less commonly as a constant infusion. We evaluated the stability and compatibility of the two drugs when aminophylline is given as a constant intravenous infusion and ceftazidime is administered simultaneously either through a y-site (piggyback method) or as a continuous infusion (constant infusion method). DESIGN: The chemical stability of intravenous aminophylline and ceftazidime in dextrose 5% and NaCl 0.9% for both methods was studied. Three different formulations of ceftazidime from the same manufacturer were studied (minibag using reconstituted ceftazidime, premixed minibag, and ceftazidime arginine). For the piggyback and constant infusion methods, samples were collected at 0, 1, and 2 hours; and 0, 6, and 24 hours, respectively. All experiments were conducted in triplicate. Samples were analyzed in duplicate by a stability-indicating HPLC assay method. OUTCOME MEASURE: Ceftazidime and aminophylline were considered stable if concentrations remained above 90 percent of the original concentrations over the time periods studied. RESULTS: Ceftazidime was determined to be compatible with aminophylline in the piggyback method. In contrast, when aminophylline and ceftazidime were admixed in the same intravenous container (constant infusion method), the two drugs were not stable. CONCLUSIONS: These data indicate that aminophylline and ceftazidime admixtures are incompatible when prepared in the same intravenous container, which may occur if both are given as a constant infusion. The two drugs are compatible when the ceftazidime is piggybacked into a primary intravenous set in which aminophylline is administered as a constant infusion.

Aminophylline↗
PubMedDate not supplied

Change in pulmonary venous admixture with varying inspired oxygen.

Pulmonary venous admixture (Qsp/Qt) was analyzed as a function of fractional concentration of inspired O2 (FIO2) in 30 patients who required postoperative mechanical ventilation. Pulmonary and radial artery blood-gas tensions and pH were measured and Qsp/Qt was calculated with FIO2 ranging from 0.21 to 1. In all patients, Qsp/Qt decreased when FIO2 was increased from 0.21 to 0.4 and then stabilized to an FIO2 of approximately 0.6. As the FIO2 was increased to 1, Qsp/Qt increased. Since the inhalation of gas mixture with FIO2 greater than or equal to 0.6 increased right-to-left intrapulmonary shunting of blood, we recommend respiratory function be evaluated during inhalation of a clinically useful concentration of O2 rather than at an FIO2 of 1.

Humans↗
PubMed1990

Stability prediction of nafamostat mesilate in an intravenous admixture containing sodium bisulfite.

The hydrolysis of nafamostat mesilate (NM) in aqueous solution was found to be accelerated by sodium bisulfite (SBS) using high-performance liquid chromatographic assay. The hydrolysis of NM catalyzed by SBS was pseudo-first-order and was considered to be a reaction between nafamostat cation (N+) and sulfite ion. The effects of SBS concentration and temperature on the hydrolysis of NM in buffer solution were examined. From the findings obtained, we estimated the compatible pH range of the intravenous admixture (mixed infusion) of NM after a constant storage time at a constant SBS concentration and temperature employing a simulated pH-profile for the mixed infusion. In order to evaluate the compatibility of the prescribed mixed infusion, the method of pH estimation for the mixed infusion was also investigated using the pH titration curve of each preparation.

Benzamidines↗
PubMed2000

Gene admixture in the silk road region of China: evidence from mtDNA and melanocortin 1 receptor polymorphism.

Mitochondrial DNA control region segment I sequences and melanocortin 1 receptor (MC1R) gene polymorphism were examined in ethnic populations in the silk road region of China. Both the frequencies of the MC1R variants and the results of mtDNA data in this region presented intermediate values between those of Europe and East and Southeast Asia, which suggested extensive gene admixture in this area and was in general agreement with previous studies. Phylogenetic analysis of the ethnic populations in the Silk Road region that based on mtDNA data didn't show expected cluster pattern according to their ethnogenesis. We suspect that a high migration rate in female among these closely related populations and other three demographic events might account for it.

Base Sequence↗
PubMed2002

Diversity at eight polymorphic Alu insertion loci in Chinese populations shows evidence for European admixture in an ethnic minority population from northwest China.

We have analyzed eight human-specific Alu insertion polymorphisms in four Chinese populations belonging to three ethnic groups (98 Hans from Shanghai, 80 Hans from Guangzhou, 85 Uyghurs, and 60 Sibos). All populations exhibited high levels of average heterozygosity, and those in Uyghur and Sibo were higher than predicted by the island model of population structure. The degree of genetic differentiation among these populations is statistically significant, and lower than those observed in most parts of the world except for Europe and Sahul (Australia and New Guinea). Phylogenetic analysis of these data with published data from 29 worldwide populations shows that there is a close genetic affinity among all the East Asian populations except for the Uyghur, and that the Uyghur population was found to lie between the East Asian and the West Asian populations on the population tree. The greater heterozygosity and the significant genotype associations between unlinked loci observed for the Uyghurs support the scenario that the Uyghurs might have originated from an admixture between Europeans and East Asians. This study also provides further support for the "out-of-Africa" hypothesis of modern human evolution in East Asia.

Biological Evolution↗
PubMed2004

The population structure of African cultivated rice oryza glaberrima (Steud.): evidence for elevated levels of linkage disequilibrium caused by admixture with O. sativa and ecological adaptation.

Genome-wide linkage disequilibrium (LD) was investigated for 198 accessions of Oryza glaberrima using 93 nuclear microsatellite markers. Significantly elevated levels of LD were detected, even among distantly located markers. Free recombination among loci at the population genetic level was shown (1) by a lack of decay in LD among markers on the same chromosome and (2) by a strictly increasing composite likelihood function for the recombination parameter. This suggested that the elevation in LD was due not to physical linkage but to other factors, such as population structure. A Bayesian clustering analysis confirmed this hypothesis, indicating that the sample of O. glaberrima in this study was subdivided into at least five cryptic subpopulations. Two of these subpopulations clustered with control samples of O. sativa, subspecies indica and japonica, indicating that some O. glaberrima accessions represent admixtures. The remaining three O. glaberrima subpopulations were significantly associated with specific combinations of phenotypic traits-possibly reflecting ecological adaptation to different growing environments.

Acclimatization↗
PubMed2006

Marker genotypes and population admixture and their association with body weight, height and relative body mass in United States federal bison herds.

Elucidating genetic influences on bison growth and body composition is of interest, not only because bison are important for historical, cultural, and agricultural reasons, but also because their unusual population history makes them valuable models for finding influential loci in both domestic cattle and humans. We tested for trait loci associated with body weight, height, and bison mass index (BMI) while controlling for estimated ancestry to reduce potential confounding effects due to population admixture in 1316 bison sampled from four U.S. herds. We used 60 microsatellite markers to model each phenotype as a function of herd, sex, age, marker genotypes, and individual ancestry estimates. Statistical significance for genotype and its interaction with ancestry was evaluated using the adaptive false discovery rate. Of the four herds, two appeared to be admixed and two were nonadmixed. Although none of the main effects of the loci were significant, estimated ancestry and its interaction with marker loci were significantly associated with the phenotypes, illustrating the importance of including ancestry in the models and the dependence of genotype-phenotype associations on background ancestry. Individual loci contributed approximately 2.0% of variation in weight, height, and BMI, which confirms the utility and potential importance of adjusting for population stratification.

Animals↗
PubMed1993

Survey of wastage from intravenous admixture in US hospitals.

The purpose of this study was to assess current wastage from intravenous systems designed for intermittent use in US hospitals. Questionnaires were mailed to pharmacy directors at 1393 randomly selected hospitals. Respondents were asked to indicate their overall percentage intravenous wastage rate, intravenous admixture policies and procedures, and wastage rates for currently used intermittent intravenous drug delivery systems. If actual data were not available, respondents were asked to provide estimates based on their perceptions of waste. A total of 237 (17.0%) usable responses were returned. The mean intravenous wastage was 2.85% (+/- 3.40) for respondents who provided actual values and 4.28% (+/- 3.83) for respondents who provided estimated values. Lower mean wastage rates were found for hospitals which: (a) received written notification of discontinued intravenous systems; (b) had an elapsed time of less than or equal to 1 hour from discontinuation of the intravenous system to notification in the pharmacy; (c) actively retrieved discontinued intravenous systems from the nursing unit; and (d) had a daily return of discontinued intravenous systems to the pharmacy. Based on actual values provided by respondents, for 9 intravenous systems the mean wastage rates were lowest for commercially prepared intermittent systems such as frozen piggyback systems {1.5% (+/- 1.4)} and piggyback systems stored at room temperature {3.2% (+/- 5.2)}, and 4.4% (+/- 16.0) for nursing-activated ADD-Vantage systems. We expected that pharmacy managers would monitor waste regularly and be able to provide actual values for wastage rates. However, only 124 (53.3%) of the respondents provided actual data.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug Packaging↗
PubMed2003

Using genetic admixture to explain racial differences in insulin-related phenotypes.

Documented differences in measures of insulin secretion and action between African Americans and European Americans may be due to either genetic or environmental factors. This study used genetic admixture (ADM), determined from approximately 20 ancestry informative markers, and a questionnaire designed to assess socioeconomic status (SES) to examine potential genetic and environmental contributions to minimal model-derived measures of insulin sensitivity (S(I)), fasting insulin, and the acute insulin response to glucose (AIR(g)) in 125 children residing in Birmingham, Alabama. The study was longitudinal in design and yielded multiple outcome measures on each subject. Mixed models analysis was used to determine if ADM and SES were independently related to S(I), fasting insulin, and AIR(g) after adjusting for confounding factors (pubertal status, adiposity, age) and for repeated testing of individuals. In this cohort, African ADM ranged from 0% (individuals with no markers reflecting African ancestry) to 100% (individuals with all 20 markers reflecting African ancestry). Results indicated that ADM was independently related to S(I) (P < 0.001) and fasting insulin (P < 0.01), with individuals having greater African ADM having a lower S(I) and a higher fasting insulin concentration. Both ADM (P < 0.001) and SES (P < 0.05) were independently related to AIR(g); children with greater African ADM or lower SES had a higher AIR(g), even after adjusting for S(I). These observations suggest that use of ADM can replace assignment of individuals to categorical racial groups; that lower S(I) and higher fasting insulin among African Americans compared with European Americans may have a genetic basis; and that higher AIR(g) among African Americans may be due to both genetic factors and to environmental factors that remain to be identified.

Adipose Tissue↗
PubMed2004

Genetic relationships and admixture among sheep breeds from Northern Spain assessed using microsatellites.

Although many research papers have studied diversity and differentiation within livestock species, genetic relationships among neighboring populations remain poorly understood. Here we apply recent methodologies to analyze the polymorphism of 14 microsatellites in 238 unrelated individuals belonging to six sheep breeds from Northern Spain to ascertain their historical relationships and the relative genetic contributions existing between populations. Individual genotypes were analyzed to assess the existence of an underlying genetic structure. Long-term and recent migration rates were estimated to identify patterns of relative genetic contribution among breeds. The complete data set showed a strong population structure derived from both different ancestral origins and some geographical patterns of recent gene flow. Two of the analyzed breeds (Black-faced Latxa and Churra) had a marked genetic background, supporting the hypothesis that, regardless of their phenotypical similarities, they have different ancestral origins. Some of the more presumably related breeds had negative long-term admixture coefficients, showing that they diverged only recently. In addition, we show how methodologies for estimation of long-term gene flow and recent patterns of migration are complementary, providing information about migration rates on different timescales.

Animals↗