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Qaulity-control plan for intravenous admixture programs. II: Validation of operator technique.

A plan for the validation of aseptic-operator technique in i.v. admixture programs and two test methods for evaluating the plan are proposed. After a new operator has been trained, the plan involves qualification of the operator through the preparation of statistically valid samples, to be followed by the random selection of samples for in-process monitoring. To test the plan, trypticase soy broth transfers were used in one hospital and Addi-Chek (Millipore Corp.) filtrations were used in another. The participants, all trained operators, initially prepared 40 test samples as a validation step. The finding of no microbial growth in these test samples permitted continuation into the monitoring phase, during which test samples were prepared randomly, one test sample out of every 25 i.v. admixtures prepared for patient use. All samples were negative for microbial growth, indicating that the operators maintained aseptic technique. These findings give evidence that the proposed testing plan is valid. The authors propose the plan as a phase of a quality control program, based on valid statistical principles, to give assurance that i.v. room operators are qualified to prepare sterile parenteral medications.

Drug Combinations↗

Bretylium tosylate intravenous admixture compatibility. I: Stability in common large-volume parenteral solutions.

The stability of bretylium tosylate in 11 common large-volume parenteral solutions was studied. Two containers of each solution, one glass and one plastic (except for mannitol and sodium bicarbonate solutions, which were available in glass only), were stored at each of the following conditions: intense light (1400-2000 foot candles), ambient room temperature with normal light, 40 degrees C, and 4 degrees C. All samples were tested at 0 and 24 hours; some samples were also tested at 48 hours and 7 days. Testing included measurement for optical density at 4000 and 600 nm, pH level, and bretylium content as determined by HPLC. The admixtures remained clear and colorless, except that mannitol precipitated out of mannitol solutions stored at 4 degrees C. No appreciable changes in pH were observed. HPLC assays showed no significant changes in bretylium tosylate concentrations. Bretylium tosylate is compatible with each of the 11 common intravenous solutions chosen for investigation under the storage conditions studied. Admixtures with mannitol should not be refrigerated, because mannitol crystallizes from solution at refrigerator temperatures.

Bretylium Compounds↗

A multiplicative random effects model for meta-analysis with application to estimation of admixture component.

A multiplicative random effects model is constructed for combining results from different studies. An EM algorithm is developed for the maximum likelihood estimator under the Empirical Bayes framework. The method is applied to estimation of the admixture component in admixed populations. The admixture estimates can be useful in genetic epidemiology and DNA fingerprinting.

Black or African American↗

Mapping by admixture linkage disequilibrium in human populations: limits and guidelines.

Certain human hereditary conditions, notably those with low penetrance and those which require an environmental event such as infectious disease exposure, are difficult to localize in pedigree analysis, because of uncertainty in the phenotype of an affected patient's relatives. An approach to locating these genes in human cohort studies would be to use association analysis, which depends on linkage disequilibrium of flanking polymorphic DNA markers. In theory, a high degree of linkage disequilibrium between genes separated by 10-20 cM will be generated and persist in populations that have a history of recent (3-20 generations ago) admixture between genetically differentiated racial groups, such as has occurred in African Americans and Hispanic populations. We have conducted analytic and computer simulations to quantify the effect of genetic, genomic, and population parameters that affect the amount and ascertainment of linkage disequilibrium in populations with a history of genetic admixture. Our goal is to thoroughly explore the ranges of all relevant parameters or factors (e.g., sample size and degree of genetic differentiation between populations) that may be involved in gene localization studies, in hopes of prescribing guidelines for an efficient mapping strategy. The results provide reasonable limits on sample size (200-300 patients), marker number (200-300 in 20-cM intervals), and allele differentiation (loci with allele frequency difference of > or = .3 between admixed parent populations) to produce an efficient approach (> 95% ascertainment) for locating genes not easily tracked in human pedigrees.

Alleles↗

Immunoglobulin allotypes and estimation of genetic admixture among populations of Kinnaur District, Himachal Pradesh, India.

Four regional populations of the Kanet (Puh, Kalpa, Sangla, and Nachar) and an endogamous group of Koli from Kinnaur District, Himachal Pradesh, India, were studied to determine the extent of genetic variation of immunoglobulin allotypes (GM, KM, and AM) and the genetic contribution from ancestral populations of Tibet and northwest India. Haplotype GM*A G showed a higher frequency in the Kanet (40-60%)-a frequency that is more comparable to Asian populations-whereas in the Koli a lower frequency was observed, which is nearer the values for populations from northwest India. The IG haplotype data suggest that the Kanet population of Kinnaur District and the northeastern population of Nepal have different European origins than the more central population of India, represented by a sample from Delhi. The present results suggest that the populations of Kinnaur District are of admixed origin with contributions of Tibetan genes of 87.3%, 51.3%, 49.9%, 40.0%, and 9.5% in the Puh, Kalpa, Sangla, and Nachar Kanet and the Koli, respectively. The genetic distance obtained from 19 loci (9 blood groups, 8 biochemical markers, GM, and KM) showed an inverse relationship between the distance of the hybrid population from the parental gene pool. The Puh Kanet, nearest the Tibetan border, had the highest proportion of Tibetan genes but showed the lowest genetic distance with Tibetans. As the geographic distance of the other regional populations of the Kanet increases from the border of Tibet, genetic distance compared with the parental Tibetan population increases and the proportion of Tibetan admixture decreases. In the Kinnaur District admixture seems to contribute largely to the present-day observed high level of genetic differentiation.

Ethnicity↗

Computerized hospital information system for an intravenous admixture service.

A computerized hospital information system as applied to a centralized intravenous admixture service in a 525-bed hospital is described. A comparison between the i.v. admixture service prior to and after the installation of the system is presented. The computerized system increased the accuracy, completeness, legibility and timeliness of data communication throughout the hospital.

Computers↗

Total nutrient admixtures: stability issues and their impact on nursing practice.

Parenteral nutrition formulations containing lipid emulsion in one container with all other components are known as total nutrient admixtures. These formulations require maintenance of solution solubility and stability as well as emulsion stability. Phenomena associated with emulsion destabilization are reviewed. The multiple factors that destabilize total nutrient admixture formulations are discussed, along with potential nursing implications.

Drug Stability↗

Compatibility of antineoplastic, antibiotic and corticosteroid drugs in intravenous admixtures.

Through the use of absorption spectroscopy and visual observations, the compatibility of selected oncologic, antibiotic and corticosteroid drugs in intravenous admixtures was determined. The six drugs used in this study were methotrexate sodium, prednisolone sodium phosphate, sodium cephalothin, 5-fluorouracil, cytarabine and vincristine sulfate. These were cross-matched in pairs, using 5% dextrose injection as the vehicle. By obtaining the ultraviolet absorption spectrum of each of the drugs alone in the 5% dextrose injection, reference of standard spectra were obtained which could be used as a comparison for the spectra of the drugs in admixture. This comparison permitted detection of any alterations in the spectrum which would suggest chemical (nonvisual) incompatibility. Of the 13 combinations examined, four pairs appeared to be chemically incompatible. These were: 5-fluorouracil and methotrexate sodium; 5-fluorouracil and cytarabine; prednisolone sodium phosphate and methotrexate sodium; and methotrexate sodium and cytarabine.

Adrenal Cortex Hormones↗

Cyclophosphamide, methotrexate, and 5-fluorouracil in a three-drug admixture. Phase I trial of 14-day continuous ambulatory infusion.

The compatibility and stability at room temperature for up to 7 days of a three-drug admixture of cyclophosphamide, methotrexate, and 5-fluorouracil (5-FU) (CMF) was established permitting the practical delivery of the combination as an infusion in an ambulatory setting. Fourteen patients received 20 courses of CMF administered on a continuous infusion schedule for 14 days of a 28-day cycle. The dose rates were fixed for 5-FU (300 mg/M2/day) and methotrexate (0.75 mg/M2/day). The cyclophosphamide dose was escalated from 25 to 50, 75, and 100 mg/M2/d. Leukopenia and thrombocytopenia were observed in two of five patients receiving the maximal dose of cyclophosphamide. No other toxicities were observed including alopecia, stomatitis or liver function abnormalities. This Phase I trial suggests that the cumulative doses of cyclophosphamide, methotrexate, and 5-FU are comparable to the maximum doses delivered as single agent infusions. Furthermore, when the infusion CMF is compared to the "standard" bolus schedule for CMF, the infusion schedule delivers 116%, 8%, and 350% of the respective three component drugs (cyclophosphamide, methotrexate, and 5-FU).

Antineoplastic Combined Chemotherapy Protocols↗

Effects of birthplace and individual genetic admixture on lung volume and exercise phenotypes of Peruvian Quechua.

Forced vital capacity (FVC) and maximal exercise response were measured in two populations of Peruvian males (age, 18-35 years) at 4,338 m who differed by the environment in which they were born and raised, i.e., high altitude (Cerro de Pasco, Peru, BHA, n = 39) and sea level (Lima, Peru, BSL, n = 32). BSL subjects were transported from sea level to 4,338 m, and were evaluated within 24 hr of exposure to hypobaric hypoxia. Individual admixture level (ADMIX, % Spanish ancestry) was estimated for each subject, using 22 ancestry-informative genetic markers and also by skin reflectance measurement (MEL). Birthplace accounted for the approximately 10% larger FVC (P < 0.001), approximately 15% higher maximal oxygen consumption (VO(2)max, ml.min(-1).kg(-1)) (P < 0.001), and approximately 5% higher arterial oxygen saturation during exercise (SpO(2)) (P < 0.001) of BHA subjects. ADMIX was low in both study groups, averaging 9.5 +/- 2.6% and 2.1 +/- 0.3% in BSL and BHA subjects, respectively. Mean underarm MEL was significantly higher in the BSL group (P < 0.001), despite higher ADMIX. ADMIX was not associated with any study phenotype, but study power was not sufficient to evaluate hypotheses of genetic adaptation via the ADMIX variable. MEL and FVC were positively correlated in the BHA (P = 0.035) but not BSL (P = 0.335) subjects. However, MEL and ADMIX were not correlated across the entire study sample (P = 0.282). In summary, results from this study emphasize the importance of developmental adaptation to high altitude. While the MEL-FVC correlation may reflect genetic adaptation to high altitude, study results suggest that alternate (environmental) explanations be considered.

Acclimatization↗

Admixture estimation using skin reflectance data.

Several different methods are suggested for the estimation of admixture proportions in hybrid populations based on skin reflectance data. These methods are applied to hybrid populations of known ancestry and yield results generally quite similar to those expected based on a simple genetic model. Results indicate the usefulness of these methods in hybridization studies and in the development and refinement of models of the genetics of skin color.

Africa↗

Generalized joint hypermobility and black admixture in school children of Bahia, Brazil.

Joint hypermobility was investigated in a sample of 3,000 school children, ages 6--7 years, in Bahia, Brazil. A sampling method was designed to assure an equal number of 50 children in the smallest size classes, when age, race, and sex were held constant. Race was classified in five subgroups to assess the proportion of black admixture. The overall frequency of generalized joint hypermobility was 2.3%. The darker the children the lower the frequency of affected children. However, this racial effect was also associated with age: The highest frequency of generalized joint hypermobility was among the youngest and less black mixed children, whereas among the oldest and darker children there was no case of joint hypermobility.

Adolescent↗

Blood polymorphisms and racial admixture in two Brazilian populations.

One thousand individuals from the southern population of Porto Alegre and 760 from the northeastern city of Natal were studied in relation to 12 and 8 genetic systems, respectively. The data thus gathered were used in different ways to estimate quantitatively the ethnic composition of individuals from these communities. More than half of the genes present in individuals classified as Black in Porto Alegre may be of White origin, while the Whites from this city have 8% of African alleles. The estimated degree of admixture in persons identified as White or Mixed in Natal is not much different among themselves. The ancestry of the total sample can be characterized as 58% White, 25% Black, and 17% Indian.

Alleles↗

Social class, admixture, and skin color variation in Mexican-Americans and Anglo-Americans living in San Antonio, Texas.

Social class may act in different ways as a barrier to gene flow in urban populations, depending on ethnicity. We test the hypothesis that biological variation is affected by social class subdivision using skin reflectance data collected for 393 Anglo-American and 930 Mexican-American adults in the major urban population of San Antonio, Texas. Two socioeconomic groups were sampled for the Anglo-American population: a middle-income transitional group and a high-income suburban group. In addition, we sampled a third socioeconomic group for Mexican-Americans: a low income barrio. Sex and age effects on skin color are minimal. Social class has no effect on skin color variation for Anglo-Americans, whereas there is a highly significant effect on social class subdivision for Mexican-Americans. Admixture estimates were derived from skin reflectance data and show that the proportion of native American ancestry decreases as social class increases.

Adult↗

Glucose tolerance and ancestral genetic admixture in six semitraditional Pacific populations.

Population-based data on 1,842 subjects from six semitraditional Pacific communities, collected in the years 1978-1983, have been compared in order to examine the hypotheses that differences in the distribution of plasma glucose concentration between populations are to some extent genetically determined, and that non-Austronesian (NAN) Melanesians are relatively resistant to glucose intolerance. Semitraditional communities were chosen for study so that the comparison would be minimally confounded by either known or as yet undetermined environmental factors associated with nontraditional living, the effects of which may vary between populations. The samples were also selected so as to provide a gradient of proportional NAN and AN admixture. They were drawn from the following regions: the highlands of Papua New Guinea, New Caledonia, Fiji, the Wallis Islands, Western Samoa, and Kiribati (formerly the Gilbert Islands). The Papua New Guinea highlanders, of entirely NAN ancestry, were regarded as the baseline population. A gradient of increasing mean 2-hr plasma glucose concentration was observed across the six populations and differences persisted between populations, after controlling for age and obesity. Variations in diet, physical activity, and degree of sociocultural modernization were not considered a sufficient or consistent explanation of these findings and they therefore lend tentative support to the hypothesis of a genetic component to variability in glucose tolerance. The relationship between population estimates of glucose tolerance and estimates of the genetic distance from the baseline NAN Melanesian sample was examined. With the notable exception of Fiji, there was evidence of a linear correlation between the two parameters.

Female↗

Power of the admixture test to detect genetic heterogeneity.

Several dominant genetic diseases which appear to be homogeneous are the expression of genetic mutations at several loci. The power to detect linkage by likelihood methods is diminished for heterogeneous, as compared to genetically homogeneous, disorders. Using a simulation approach and two pedigrees typical of those available for the study of a dominant disease (with expected lod scores of 0.43 and 1.00 at theta = 0.05 and PIC = .59), I have evaluated the power to detect genetic heterogeneity by using the admixture test. Linkage power was determined by varying the number of families available for study, the recombination fraction (theta), the informativity of the hypothetical marker, and the proportion of linked families, alpha. For moderate and small values of alpha it is feasible to detect genetic heterogeneity once linkage has been established; rarely will it be possible to detect linkage and heterogeneity simultaneously given a limited number of small or moderate pedigrees.

Epidemiologic Methods↗

The admixture maximum likelihood test: a novel experiment-wise test of association between disease and multiple SNPs.

Disease association studies often test large numbers of markers, and various methods have been proposed to correct for multiple testing. In this paper, we propose an admixture maximum likelihood approach that estimates both the proportion of associated single nucleotide polymorphisms (SNPs) and their typical effect size. We assessed this method and compared it with several previously proposed approaches by simulation. The maximum likelihood approach performed similarly to or better than all other tests across a wide range of alternative hypotheses. The rank truncated product method also had good power, though somewhat inferior to the maximum likelihood approach in most cases. A simple Bonferroni correction performed best only when the number of associated SNPs was small.

Genetic Predisposition to Disease↗