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Biomedical subjects

C Horne

Publications and source records attributed to C Horne.

At least 19 recordsLinked to original sources
PubMed2003

Intact fetal cell isolation from maternal blood: improved isolation using a simple whole blood progenitor cell enrichment approach (RosetteSep).

Isolation and analysis of intact fetal cells in maternal blood is an attractive method of non-invasive prenatal diagnosis; however, detection levels are not optimal. The poor sensitivity and inconsistent recovery of fetal cells is compounded by small numbers of circulating fetal cells and loss of fetal cells during enrichment procedures. Optimizing selection criteria by utilizing less complicated methods for target cell enrichment is essential. We report here salutary results using a simple density-based depletion method that requires neither MACS (magnetic-activated cell sorting) nor flow cytometric separation for enrichment of progenitor cells. Maternal blood samples (n = 81) were obtained from women prior to invasive prenatal genetic diagnostic procedures and processed randomly within 24 h using one of two density-based enrichment methods. For progenitor cell enrichment, samples (n = 49) were labeled with a RosetteSep progenitor antibody cocktail to remove unwanted mature T-cells, B-cells, granulocytes, natural killer cells, neutrophils and myelomonocytic cells. For CD45-negative cell enrichment, samples (n = 14) were labeled with RosetteSep CD45 antibody to remove unwanted maternal white cells. The desired cellular fraction was collected and analyzed by either fluorescent in situ hybridization (FISH) or real-time PCR for the presence of intact fetal cells and to quantify Y-chromosome-specific DYS1 sequences, respectively. Overall, FISH and real-time PCR correct detection rates for the progenitor cell enrichment approach were 53% and 89% with 3% (1 out of 30 cases) and 0% false-positive detection, respectively. Fetal sequences were detected in the range from 0.067 to 1.167 genome equivalents per milliliter of blood. No fetal cells were detected using the CD45-negative enrichment method. Flow cytometric analysis of cord blood showed that a unique myeloid population of cells was recovered using RosetteSep trade mark progenitor enrichment compared with the CD45-negative enrichment method. Sensitivity of the RosetteSep progenitor enrichment approach for detection of fetal cells in this pilot study shows great promise with recovery of cells that are suitable for FISH and automated microscope scanning. This simple and rapid method may also allow expansion in culture and characterization of the fetal cell type(s) that circulate in maternal blood, hence, greatly improving reliability of non-invasive prenatal diagnosis.

Blood Cells↗
PubMed2000

Distribution of DRB1 and DQB1 HLA class II alleles in occupational asthma due to western red cedar.

Occupational asthma caused by western red cedar is a common problem in sawmill industries. The objective of this study was to examine a possible association of human leukocyte antigen (HLA) class II genetic markers with susceptibility or resistance to western red cedar induced asthma. The distribution of DRB1 and DQB1 HLA class II alleles and DRB1-DQB1 haplotypes was studied in 56 Caucasian patients with proven red cedar asthma and 63 healthy Caucasian control subjects exposed to red cedar dust. DRB1 and DQB1 high resolution typing was performed by the polymerase chain reaction-based method. Patients with red cedar asthma had a higher frequency of HLA DQB1*0603 and DQB1*0302 alleles compared to a group of healthy exposed control subjects and a reduced frequency of DQB1*0501 allele. The frequency of the DRB1*0401-DQB1* 0302 haplotype was increased and the DRB1*0101-DQB1*0501 haplotype was reduced. These findings suggest that genetic factors such as human leukocyte antigen class II antigens may be associated with susceptibility or resistance to development of red cedar asthma.

Adult↗
PubMed1998

HLA-DR class II associations with rubella vaccine-induced joint manifestations.

HLA class II (HLA-DR) frequencies were examined in relation to incidence of acute arthralgia or arthritis in 283 white women who had received RA27/3 rubella vaccine (n = 146) or placebo (n = 137) postpartum. Leukocyte DNA was molecularly typed for HLA-DRB1 gene expression. Univariate analysis revealed higher frequencies of DR2 (odds ratio [OR], 4.8; 95% confidence interval [CI], 1.2-18.8) and DR5 (OR, 7.5; 95% CI, 1.5-37.5) but lower frequencies of DR4 (OR, 2.3; 95% CI, 1.1-4.9) and DR6 (OR, 2.8; 95% CI, 1.4-5.8), in rubella vaccinees compared with placebo recipients with arthropathy. Logistic regression modelling of DR, treatment, age, time postpartum, and arthropathy revealed that the odds of developing arthropathy was 1.9 times greater (95% CI, 1.07-3.44) after rubella vaccine than placebo. Risk for arthropathy (regardless of rubella vaccination) was also influenced by DR interactions: odds were 8 times greater in individuals with both DR1 and DR4 (95% CI, 1.45-44.02) and 7.1 times greater with both DR4 and DR6 present (95% CI, 1.85-27.52), suggesting that coexpression of these specificities may predispose to postpartum arthropathy.

Adolescent↗
PubMed1995

Predicting nursing home admissions among incontinent older adults: a comparison of residential differences across six years.

Whether or not rates of nursing home admissions among elders with urinary incontinence varied by their place of residence was investigated. We also examined whether any observed residential differences could be accounted for by factors other than incontinence that are known to influence rates of institutionalization. Data from the Longitudinal Study on Aging (1984-1990) were used to examine a sample who at baseline lived in community settings and reported problems with urinary incontinence (n = 719). Analyses indicate that residents of less urbanized and thinly populated nonmetropolitan counties were more likely to have a nursing home admission than elders in any other residential context. More importantly, these residential differences persisted in multivariate logistic regression models after controls were introduced for sociodemographic characteristics, measures of health status, and indicators of the social support networks of the elders.

Activities of Daily Living↗
PubMed1993

Effects of angiotensin-converting enzyme inhibition on renal sodium handling after furosemide injection.

The goal of this study was to quantitate the effect of angiotensin-converting enzyme inhibition on renal sodium handling after furosemide injection. The study was carried out on low and normal salt intake to assess potential interaction with salt balance. Eighteen healthy normotensive volunteers were examined in a double placebo-controlled parallel group design. Subjects were randomly put on either low-salt (20 mmol/day) or normal-salt (110 mmol/day) diet. In either arm of the diet volunteers were first treated orally with placebo for 1 week and subsequently with 2.5 mg/day of the angiotensin-converting enzyme inhibitor cilazapril for another 1 week. Cumulative 24-h urinary sodium excretion was measured on the 6th day of the respective week after sham injection and on the 7th day after injection of 40 mg furosemide. Compared to pretreatment with placebo, pretreatment with cilazapril resulted in a higher cumulative sodium excretion after furosemide injection (day 7) than after the sham injection (day 6) on both salt intakes. The difference in natriuresis (cilazapril versus placebo) was evident 2 and 3 h after injection of furosemide. Neither the time of onset nor the magnitude of antinatriuresis were affected by cilazapril. Following furosemide angiotensin II increased significantly even after cilazapril pretreatment. Cilazapril tended to reduce urinary furosemide excretion. At any given urinary furosemide concentration, the increment in urinary sodium excretion was significantly greater with cilazapril irrespective of salt intake. The study shows that (a) cilazapril increases furosemide-induced natriuresis irrespective of salt intake, (b) antinatriuresis is not affected by cilazapril, and (c) angiotensin II levels rise after furosemide on cilazapril in therapeutic doses.

Adult↗
PubMed1993

Rapid DNA typing for class II HLA antigens: subtyping of DRw52-associated DRB1 alleles.

Serologic typing for MHC class II antigens is incapable of identifying important subtypes for certain DRB1 alleles and occasionally leads to errors of assignment, particularly with the DR antigens associated with DRw52. To simplify DNA typing of DRw52-associated DRB1 alleles, we have developed a new rapid method using PCR-RFLP. The PCR-RFLP method is based on allele-specific amplification followed by digestion of PCR-amplified DNA with restriction enzymes. Group-specific amplification of the second exon of DR3, DR5, DR6 and DR8 was achieved using a 5' primer specific for the first hypervariable region sequence common to all alleles in this group and generic 3' primers. Human genomic DNA was amplified in a Perkin-Elmer Thermocycler. The presence of a 265 bp fragment was confirmed by agarose gel electrophoresis. Restriction enzyme digestion using Rsa I followed by polyacrylamide gel electrophoresis gave a pattern unique for some alleles and placed the remainder in subgroups. Digestion of the PCR product with one or two of the following enzymes (Asp 700, Hae II, Mnl I, Mbo II, Ksp I and Hph I) permitted the identification of 21 of the 22 alleles. DRB1*1103 and DRB1*1104 are not distinguished by this method and can be distinguished by SSOP or by using a specific 3' primer. For some heterozygous combinations, additional primers are used to provide full subtyping. This method provides a rapid and less costly alternative to PCR-SSOP for DRw52 subtyping in the smaller laboratory as only one amplification is required (two primers) for the majority of samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1992

Bioavailability study of two different verapamil formulations.

Relative bioavailability and bioequivalence of two oral verapamil preparations were investigated (dosage 80 mg, film-coated tablets as reference, dragées as test formulation). The clinical study was performed in a 2-period-cross-over design with 16 male healthy volunteers (mean age 28.8 +/- 3 years). The active metabolite norverapamil was included in the investigation. To assess bioequivalence several pharmacokinetic characteristics (i.e. AUC(o-oo), Cmax, tmax) were taken into account. Shortest 90% confidence intervals were calculated based on parametric (ANOVA, ANOVAlog) and non-parametric (Wilcoxon, Mann-Whitney) statistical tests. A positive decision for bioequivalence was accepted if the confidence intervals did not exceed the limits of 80-120% for AUC and 70-130% for Cmax. A mean relative bioavailability of 127% for the test preparation was found. Thus, bioavailability of the dragées is marked higher than bioavailability of the film-coated tablets.

Adult↗
PubMed1992

Job satisfaction among hospital nurses: facility size and location comparisons.

Despite recent declines in turnover and vacancy rates, maintaining a stable nursing staff continues to be critical to the effective operation of American hospitals. Job satisfaction is a pivotal element in nurse retention, and organizational theory suggests that some of the factors that influence job satisfaction vary by facility size. This is a study of job satisfaction among a sample of 731 nurses providing direct patient care in 22 hospitals. The sample includes approximately equal numbers of nurses employed in very small rural hospitals (1-49 beds), medium sized facilities located in small towns (50-99 beds), and larger metropolitan institutions (> 100 beds). Differences by hospital size were observed in overall job satisfaction and in five sub-dimensions of that concept (i.e., professional status, task requirements, pay, organizational policies, and autonomy). With the exception of pay, the results indicated that nurses employed in the very small rural hospitals were more satisfied with their jobs. Differences by hospital size were also observed in the personal characteristics of the nurses, several specific aspects of their job, and in their perceptions of job mobility. A set of four hierarchically nested ordinary least squares regression models indicated that job-specific characteristics were the most powerful predictors of job satisfaction.

Attitude of Health Personnel↗
PubMed1991

AF-DX 116, a cardioselective muscarinic antagonist in humans: pharmacodynamic and pharmacokinetic properties.

Effects of AF-DX 116, a cardioselective antagonist, on M cholinergic receptors (M-ChR) were studied in healthy volunteers. Occupancy of M-ChR subtypes by drug present in plasma samples (radioreceptor assay) was compared with these effects. After an intravenous dose of AF-DX 116 saturating greater than 90% of cardiac M2-ChR, an increase in heart rate by 25 beats/min was observed. This cardiac receptor occupancy and effect wore off with a parallel time course within 10 hours. No inhibition of salivary flow was observed, coinciding with a lack of M3-ChR blockade in the radioreceptor assay. Beta-adrenergic receptor blockade by propranolol did not affect either of the effects. No indication for active metabolites or stereoselective drug metabolism was found comparing HPLC and receptor assay for drug concentrations in plasma. We conclude that AF-DX 116 may be a useful drug for the treatment of bradycardia. Its lack of troublesome side effects is the result of its selectivity for cardiac M-ChR.

Adult↗
PubMed1990

Isotype modulation of idiotypic expression in recombinant isotypic variants of MOPC 315.

The influence of the CH1 domains of various isotypes on the expression of four Id of the IgA 2 mouse myeloma protein MOPC 315 was assessed. To this end, mammalian expression vectors containing the rearranged MOPC 315 VH gene along with the H chain genes of various isotypes were constructed. These vectors were then transfected into the L chain-expressing MOPC 315.26 cell line to produce the rIg. The effect of polyvalency on the ability of Ig to bind anti-idiotypic antibodies was tested by comparing idiotypic expression in a competitive ELISA using reduced and nonreduced MOPC 315 IgA and IgM species. Reduction produced a two- to fivefold decrease in their ability to inhibit the binding of three anti-idiotypic antibodies, but not that of the functionally univalent antibody D10. In contrast, reduction of MOPC 315 IgG proteins did not affect the binding of the anti-Id mAb, indicating that reduction of the interchain disulfide bonds did not alter idiotypic expression. The expression of idiotopes on reduced mouse rIgA, IgM and IgG and human IgG MOPC 315 molecules was then compared. The results showed that both human and mouse IgG recombinant antibodies exhibited an enhanced expression of the idiotopes recognized by antibodies D10 and F1, as compared to MOPC 315 IgA and IgM molecules. In contrast, the expression of idiotopes recognized by A2 and G3 mAb was not influenced by the H chain isotype. These data support the hypothesis that the conformation of certain idiotopes is modulated by the isotype of the CH1 domain.

Alkylation↗
PubMed1987

Fluorimetric determination of levoprotiline in human plasma after thin-layer chromatographic or high performance liquid chromatographic separation.

The quantitative determination of the new antidepressant drug levoprotiline, the R-(-)-enantiomer of oxa-protiline (a-[methylamino)methyl)-9,10-ethanoanthracene-9(10H)-ethanol), in human biological material is described. Analysis is performed by alkaline extraction with n-heptane-isopropanol, subsequent fluorescence derivatisation with NBD chloride (4-chloro-7-nitrobenzofurazan), thin layer or high performance liquid chromatography, and fluorimetric measurement of the derivatisation product (lambda max ex. = 470 nm, lambda max em. = 525 nm). The sensitivity of the procedure (detection limit less than 1 ng/ml) permits the performance of pharmacokinetic studies after therapeutic doses.

Anthracenes↗
PubMed1987

Use of a germanium detector to optimize scatter correction in SPECT.

A collimated germanium detector with an energy resolution of 1 keV full width at half maximum at 140 keV was used to measure the energy spectrum of radiation emitted from a test object containing an asymmetric distribution of 99mTc and nonuniform attenuation. Energy spectra were recorded from 24 positions around the object and convolved with Gaussian functions to simulate data that would have been acquired with a scintillation camera. The scatter fraction was computed from the convolved spectra in conjunction with a scatter-free reference spectrum. After adding appropriate Poisson noise, a technique based on maximizing the signal to noise ratio was developed to optimally subtract the scatter fraction from the recorded counts. SPECT imaging of the test object was performed to evaluate the correction technique.

Germanium↗