PubMed Health⌕ Search

Biomedical subjects

J P Foley

Publications and source records attributed to J P Foley.

At least 19 recordsLinked to original sources
PubMed2002

Rapid estimation of octanol-water partition coefficients using synthesized vesicles in electrokinetic chromatography.

Vesicle electrokinetic chromatography (VEKC) using vesicles synthesized from the oppositely charged surfactants cetyltrimethylammonium bromide (CTAB) and sodium octyl sulfate (SOS) and from the double-chained anionic surfactant bis(2-ethylhexyl)sodium sulfosuccinate (AOT) was applied to the indirect measurement of octanol-water partition coefficients (log Po/w). A variety of small organic molecules with varying functional groups, pesticides, and organic acids were evaluated by correlating log Po/w and the logarithm of the retention factor (log k') and comparing the calibrations. A linear solvation energy relationship (LSER) analysis was conducted to describe the retention behavior of the vesicle systems and compared to that of octanol-water partitioning. The solute hydrogen bond donating behavior is slightly different with the vesicle interactions using CTAB-SOS vesicles as compared to the octanol-water partitioning model. The AOT vesicle and octanol-water partitioning systems showed similar partitioning characteristics. VEKC provides rapid separations for determinations of log Po/w in the range of 0.5 to 5 using CTAB-SOS vesicles and 0 to 5.5 using AOT vesicles.

Cetrimonium↗
PubMed2001

Reduction in matrix-related signal suppression effects in electrospray ionization mass spectrometry using on-line two-dimensional liquid chromatography.

The effect of liquid chromatographic separation on matrix-related signal suppression in electrospray ionization mass spectrometry (LC-ESI-MS) was investigated. A method incorporating on-line two-dimensional liquid chromatography mass spectrometry (LC/LC-MS) was developed to compensate for matrix effects and signal suppression in qualitative and quantitative analysis. The LC/LC-MS(MS) approach was successfully applied for single-component and multicomponent analysis in a variety of complex matrixes. It was demonstrated that matrix-related signal suppression could be induced solely by (i) column overload, (ii) matrix component-analyte coelution, or a combination of each. Application of on-line orthogonal LC/LC separations can be effective in reducing both causes of matrix-related signal suppression effects i.e., column overload and matrix-analyte coelution for a variety of LCn/MSn applications.

Animals↗
PubMed2001

Determination of octanol-water partition coefficients of pesticides by microemulsion electrokinetic chromatography.

Microemulsion electrokinetic chromatography (MEEKC) was evaluated as a screening tool for the indirect measurement of octanol-water partition coefficients (log Po/w) of pesticide compounds. Over 80 pesticide compounds representing a variety of structural characteristics were studied, and good correlation of log Po/w with the logarithm of the retention factor was found. The microemulsion system studied allowed the separation of compounds in the log Po/w range of -1 to 7. In addition, a smaller set of simple organic molecules that vary in structural features was evaluated and compared to the pesticide log Po/w calibration. The pesticide and simple organic molecule log Po/w calibration lines were statistically similar. This suggests that a universal set of standard compounds may be employed for the log Po/w calibration to provide measurements for a variety of compounds with good accuracy.

Calibration↗
PubMed2000

Impact of socioeconomic status and race on clinical parameters of patients undergoing radical prostatectomy in an equal access health care system.

OBJECTIVES: To analyze the relationships among socioeconomic status (SES), race, and the clinical parameters of patients undergoing radical prostatectomy (RP) in an equal access health care system. METHODS: The Department of Defense Center for Prostate Disease Research longitudinal prostate cancer database from multiple military institutions was used to analyze the clinical, pathologic, and outcome data of 1058 patients with localized (Stage T2c or lower) prostate cancer and a preoperative prostate-specific antigen (PSA) level of 20 ng/mL or less who underwent RP between January 1987 and December 1997. Military rank (officer versus enlisted) was used as a surrogate measure of SES. RESULTS: The percentage of patients with pathologic Gleason grade 7 or greater prostate cancer was higher in enlisted (45%) than in officer (37%) patients (P = 0. 021). However, no difference was found between these groups with respect to pathologic stage or biochemical recurrence rates. African Americans presented at a younger age (P = 0.003), with a higher pretreatment PSA level (P = 0.001), and demonstrated higher biochemical recurrence rates than other ethnic groups (P = 0.037). The Cox proportional hazards analysis showed that a lower SES (P = 0.010) but not African American race (P = 0.696) was an independent predictor of a higher grade (Gleason grade 7 or higher) cancer. However, biochemical progression was more common in African American men (P = 0.035) and was not related to SES (P = 0.883). CONCLUSIONS: In an equal access health care system, patients of lower SES presented with higher grade prostate cancer at the time of RP. However, only African American race predicted biochemical progression after RP.

Age Factors↗
PubMed2000

The effect of stationary-phase pore size on retention behavior in micellar liquid chromatography.

One of the limitations that has restricted the applicability of micellar liquid chromatography (MLC) is the weak eluting power of micellar mobile phases compared to conventional hydro-organic mobile phases used in reversed-phase liquid chromatography. This may be the result of Donnan or steric exclusion of the micelles from the pores of the stationary phase, within which nearly all (> or = 99%) of the stationary phase resides and the analytes spend most of their time. To determine whether wide-pore stationary phases would overcome this limitation in MLC, several C8 and C18 stationary phases ranging from 100 to 4000 A were investigated using a diverse set of test solutes and micellar solutions of anionic, neutral, and cationic surfactants as mobile phases. With the larger pore size stationary phases, the eluting power of the MLC mobile phases was enhanced with all surfactant types, the greatest effect being with the neutral surfactant. Differences in retention behavior were observed between various solute types and between the C8 and C18 stationary phases. These differences appear to be related to the relative hydrophobicity of the solutes and to differences in the surfactant-modified stationary phases. Partitioning behavior of representative solutes on the large-pore C8 and C18 columns was shown to follow the three-phase partitioning model for MLC. Methylene group selectivity data showed only minor differences in the stationary-phase characteristics between the small- and large-pore size C18 columns. The true eluting power of micellar mobile phases was revealed with wide-pore stationary phases and was demonstrated by the separation and elution of an extended series of alkylphenones on C18 columns.

Algorithms↗
PubMed2000

Dual-opposite injection electrokinetic chromatography for the unbiased, simultaneous separation of cationic and anionic compounds.

The concept of dual opposite injection in capillary electrophoresis (DOI-CE) for the simultaneous separation, under conditions of suppressed electroosmotic flow, of anionic and cationic compounds with no bias in resolution and analysis time, is extended to a higher pH range in a zone electrophoresis mode (DOI-CZE). A new DOI-CE separation mode based on electrokinetic chromatography is also introduced (DOI-EKC). Whereas conventional CZE and DOI-CZE are limited to the separation of charged compounds with different electrophoretic mobilities, DOI-EKC is shown to be capable of separating compounds with the same or similar electrophoretic mobilities. In contrast to conventional EKC with charged pseudostationary phases that often interact too strongly with analytes of opposite charge, the neutral pseudostationary phases appropriate for DOI-EKC are simultaneously compatible with anionic and cationic compounds. This work describes two buffer additives that dynamically suppress electroosmotic flow (EOF) at a higher pH (6.5) than in a previous study (4.4), thus allowing DOI-CZE of several pharmaceutical bases and weakly acidic positional isomers. Several DOI-EKC systems based on nonionic (10 lauryl ether, Brij 35) or zwitterionic (SB-12, CAS U) micelles, or nonionic vesicles (Brij 30) are examined using a six-component test mixture that is difficult to separate by CZE or DOI-CZE. The effect of electromigration dispersion on peak shape and efficiency, and the effect of surfactant concentration on retention, selectivity, and efficiency are described.

Anions↗
PubMed2000

Investigation of the chiral surfactant N-dodecoxycarbonylvaline in electrokinetic chromatography: improvements in elution range and pH stability via mixed micelles and vesicles, and the hydrophobicity determination of basic pharmaceutical drugs.

The chiral surfactant dodecoxycarbonylvaline (DDCV) has proven to be an effective pseudostationary phase for the separation of many enantiomeric pharmaceutical compounds. In this study the elution range and the prediction of octanol-water partitioning for the DDCV micellar system was examined. Through incorporation of DDCV in mixed micelles and unilamellar vesicles, enhancement of the elution range was observed. The mixed micelles contained a second anionic surfactant, sodium dodecyl sulfate (SDS), while the vesicles were composed of DDCV and the cationic surfactant cetyltrimethylammonium bromide (CTAB). Enantioselectivity, as well as other chromatographic and electrophoretic parameters, were compared between the mixed micelles, vesicles, and DDCV micelles. The hydrophobicity of the DDCV system was also evaluated as a predictor of n-octanol-water partition coefficients for 15 beta amino alcohols. The correlation between the logarithm of the retention factor (log k) and log P(ow) for seven hydrophobic beta-blockers and eight beta-agonists were r2 = 0.964 and r2 = 0.814, respectively.

Adrenergic beta-Antagonists↗
PubMed1999

An optical device with variable astigmatic power.

A new variable power cross-cylinder lens set is described. It differs from the well known Stokes variable power cross-cylinder lens set, which is made of cylinder lenses of equal but opposite power, in that in the new variable power cross-cylinder lens set both lens elements are identical. These elements can be sphero cylindrical of any type and can be designed to give the same effect as a Stokes lens set or create a spherical bias or offset of a desired amount. The action of this lens set is analyzed using 3-dimensional refractive space.

Astigmatism↗
PubMed1998

Comparison of the retention behavior of beta-blockers using immobilized artificial membrane chromatography and lysophospholipid micellar electrokinetic chromatography.

We have demonstrated that significant differences exist between the retention of eight beta-blockers analyzed with immobilized artificial membrane (IAM) and lysophospholipid micellar electrokinetic capillary (LMEKC) chromatographic methods. The general retention trends are maintained with highly hydrophilic compounds such as atenolol eluting first and more hydrophobic compounds such as propranolol eluting last. The retention order, however, is different and would result in major ranking differences. LMEKC demonstrates a better correlation with liposomal partitioning (R2 = 0.95) than does IAM chromatography (R2 = 0.60). LMEKC, with its higher efficiency, can allow a more specific evaluation of lipophilicity than IAM chromatography and is useful in the analysis of pharmaceutical candidates, particularly for ranking purposes.

Adrenergic beta-Antagonists↗
PubMed1998

Enhanced separation of antidepressant drugs using a polymerized nonionic surfactant as a transient capillary coating.

The separation of seven structurally similar antidepressant drugs (amitriptyline, nortriptyline, imipramine, desipramine, protriptyline, doxepin, and nordoxepin) was achieved in under 15 min using a novel nonionic micelle polymer, poly(n-undecyl-alpha-D-glucopyranoside) (PUG) by use of capillary zone electrophoresis (CZE). Systematic studies with varying polymer concentration, pH, and percent organic modifier were conducted in order to find the optimum conditions for baseline separation of the seven tricyclic antidepressants. In addition, equations for capacity factor were used to estimate the extent of what was initially thought to be micelle analyte interaction. A series of calculations show that a modified CZE system (PUG-CZE) was the actual mode of separation. Thus, our study concluded that PUG functioned in a non-electrokinetic chromatography mode.

Antidepressive Agents↗
PubMed1998

Prolonged prostate-specific antigen response in flutamide withdrawal syndrome despite disease progression.

Flutamide withdrawal syndrome is characterized by a decrease in prostate-specific antigen (PSA) after flutamide withdrawal in a subset of patients with progressing metastatic carcinoma of the prostate. It is generally hypothesized to be due to a point mutation in the androgen receptor that allows the antiandrogen to function as an agonist, leading to a dramatic and rapid PSA response. We describe a patient with androgen-independent prostate cancer in whom PSA continued to decrease for a period of 15 months after flutamide withdrawal. With continuing fall in PSA, the patient had unequivocal progression of disease seen on bone scan. This case illustrates the potential decoupling of PSA response from disease status in flutamide withdrawal. It also illustrates the need for continued clinical evaluation of patients with metastatic prostate cancer, even in the face of PSA response.

Aged↗
PubMed1998

Incidence of fecal and urinary incontinence following radical perineal and retropubic prostatectomy in a national population.

PURPOSE: Since 1991 we have performed more than 300 anatomical radical perineal prostatectomies at Brooke Army and Wilford Hall Medical Centers, and were initially aware of 8 patients who presented with unsolicited postoperative fecal incontinence. We determined the incidence of fecal and urinary incontinence following radical prostatectomy, defined parameters to identify patients at risk for fecal complaints following radical prostatectomy, and estimated the impact of fecal incontinence on lifestyle and activities. MATERIALS AND METHODS: Initially a validated 26-question telephone survey was used to evaluate 227 patients who had previously undergone radical prostatectomy at 1 of our 2 institutions. Based on results of the telephone survey a national survey was mailed to 1,200 radical prostatectomy patients randomly selected from a nationwide database of Department of Defense health care system beneficiaries. All patients had undergone radical perineal or retropubic prostatectomy at least 12 months before being contacted for the survey. RESULTS: Responses to the telephone survey from 227 patients revealed that fecal incontinence was a problem after radical retropubic (5%) and perineal (18%) prostatectomy and less than 50% of those with fecal incontinence had told the physician. Our mail survey (response rate 80% and 78% usable for analysis, 784 radical perineal and 123 perineal) strongly indicated that fecal incontinence after radical prostatectomy is a problem nationwide. Frequency of fecal incontinence (daily, weekly, monthly or less than monthly occurrences) was significantly higher among radical perineal (3, 9, 3 and 16%) compared to retropubic prostatectomy (2, 5, 3, and 8%) patients (p=0.002). Fecal incontinence had a significant negative effect on patient social or entertainment activities (p=0.029), and travel and vacation plans (p=0.043). Radical perineal compared to retropubic prostatectomy patients were more likely to wear a pad for stool leakage (p=0.013), experienced more accidents (p=0.001), had larger amounts of stool leakage (p=0.002) and had less formed stools (p=0.001). Of radical perineal prostatectomy patients only 14% and of retropubic only 7% with fecal incontinence had ever told a health care provider about it, even when the incontinence was severe. Responses to our survey concerning urinary incontinence showed that radical perineal prostatectomy patients had a lower rate of urinary incontinence immediately after prostatectomy compared to retropubic (79 versus 85%, p=0.043). A higher proportion of perineal patients reported that all urinary leakage had ceased, that is full continence had returned (perineal 70%, retropubic 53%, p=0.001). A smaller proportion of perineal patients found it necessary to wear a pad to protect from urinary incontinence (perineal 39%, retropubic 56%, p=0.004). CONCLUSIONS: Fecal incontinence following radical prostatectomy occurs more frequently than previously recognized. In general fecal incontinence among radical perineal and retropubic prostatectomy patients surpasses the expected incidence rate of 4% for this age group (60 to 70 years) but incidence is significantly higher for radical perineal prostatectomy patients. However, radical perineal prostatectomy patients have a significantly lower incidence of urinary incontinence than those treated with retropubic prostatectomy. Surgeons who perform radical retropubic and perineal prostatectomy should be aware of the possibility of fecal and/or urinary incontinence and associated symptoms.

Activities of Daily Living↗
PubMed1997

Method of analysis of recombinant acidic fibroblast growth factor by capillary electrophoresis.

Fibroblast growth factors are a series of well characterized proteins that have intriguing pharmacological properties. Acidic fibroblast growth factor (aFGF) recently appeared in the literature for its efficacy in spinal cord repair in rats. The protein has proven difficult to analyze by capillary electrophoresis, because it has a tendency to unfold, aggregate and precipitate, especially near and above physiological temperatures. By studying the turbidity of capillary electrophoresis running buffers and aFGF at 50 degrees C, conditions were found that stabilize the aFGF solution, thereby allowing the capillary electrophoretic separation of the protein from its recombinant production impurities. The buffer system employs 50 mM phosphate buffer at pH 2.5 with 0.25% hydroxypropylmethylcellulose (HPMC) additive. This system provided the best efficiency and selectivity of the systems studied and was developed for pharmaceutical purity analysis.

Buffers↗
PubMed1997

Influence of the inorganic counterion on the chiral micellar electrokinetic separation of basic drugs using the surfactant N-dodecoxycarbonylvaline.

The chiral surfactant N-dodecoxycarbonylvaline (DDCV) has previously been used with a sodium counterion in micellar electrokinetic chromatography (MEKC) separations of beta-blockers (pindolol, atenolol, metoprolol, acebutolol, alprenolol, oxprenolol and propranolol), beta-agonists (N-methylpseudoephedrine, pseudoephedrine, ephedrine and norephedrine) and phenolic amino alcohols (norphenylephrine, synephrine, octopamine and salbutamol) in this laboratory. In the present study, we investigated the effects of three monovalent counterions--Li+, Na+ and K+--on the peak shape, efficiency, selectivity and retention of these 15 chiral pharmaceutical compounds with DDCV micelles. A much better (more symmetrical) peak shape was observed when Li+ was employed, due to a better if still imperfect match of analyte and counterion mobilities; average asymmetry factors in LiDDCV, NaDDCV, and KDDCV buffers were 1.9, 3.7, and 4.2, respectively. An increase in efficiency of 50-100% for hydrophobic solutes and over 100% for many hydrophilic solutes was also observed in LiDDCV compared to NaDDCV and KDDCV, probably due to enhanced mass transfer. The influence of an organic modifier (acetonitrile) in the separation buffer was also studied for the LiDDCV, NaDDCV and KDDCV systems. Although a concentration of either 0 or 5% acetonitrile resulted in the best enantiomeric resolution for most analytes, the most hydrophobic solutes (alprenolol and propranolol) required the addition of 20-25% ACN. Due to differences in the conductance of Li+, Na+ and K+, the advantage of using Li+ as the counterion for anionic DDCV micelles (better peak shape, higher efficiency and resolution, with shorter analysis times), although apparent for comparisons at a given applied voltage, is more significant when considered in the more appropriate context of equivalent Joule heating.

Anions↗
PubMed1997

Facilitated radical perineal prostatectomy with the Brooke Bookwalter retractor blade.

With the resurgent interest in radical perineal prostatectomy, a variety of enhancements have been made to the procedure. We describe herein the use of a retractor blade that allows full mobilization of the seminal vesicles and vasa prior to prostatic apical dissection, thus facilitating bladder neck-sparing radical prostatectomy. This retractor system dramatically improves visualization of the seminal vesicles and prostatic pedicles, allowing a single surgeon to perform this procedure easily.

Humans↗
PubMed1997

Dermatoses of the glans penis and prepuce.

A wide range of infectious, neoplastic, and inflammatory dermatoses can affect the glans penis or prepuce. Some are unique to the genitalia. Other more common dermatoses may have a unique appearance when they involve genital skin and mucosa. A thorough understanding of regional anatomy and a systematic diagnostic approach are helpful in the management of a refractory penile dermatosis. We review embryology and regional anatomy, drug-induced eruptions, allergic and irritant dermatitis, infection, neoplasia, and traumatic and inflammatory dermatoses as they relate to the glans and prepuce. Our discussion focuses on the clinical features, office laboratory studies, and histopathologic findings that assist in diagnosis and treatment.

Drug Eruptions↗