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Hwang SS, Park YH, Lee CB, Jung YJ. Spontaneous rupture of hydronephrotic kidney during pregnancy: value of serial sonography. JOURNAL OF CLINICAL ULTRASOUND : JCU 2000; 28:358-360. [PMID: 10934336 DOI: 10.1002/1097-0096(200009)28:7<358::aid-jcu7>3.0.co;2-e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hydronephrosis during pregnancy is common but rarely results in renal rupture. We report an unusual case of spontaneous rupture of a hydronephrotic kidney during pregnancy. Although we could not predict the renal rupture on the basis of sonographic findings, serial sonography was useful in the early detection and management of the rupture.
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Abstract
BACKGROUND The Memorial Symptom Assessment Scale Short Form (MSAS-SF), an abbreviated version of the Memorial Symptom Assessment Scale, measures each of 32 symptoms with respect to distress or frequency alone. A physical symptom subscale (PHYS), psychologic symptom subscale (PSYCH), and global distress index (GDI) can be derived from the Short Form. We validated the MSAS-SF in a population of cancer patients. METHODS Two hundred ninety-nine cancer patients examined at the Section of Hematology/Oncology completed the MSAS-SF and the Functional Assessment Cancer Therapy (FACT-G). The Karnofsky performance status (KPS), extent of disease (EOD), and demographic data were assessed. The Cronbach alpha coefficient was used to assess internal reliability. MSAS-SF subscales were assessed against subscales of the FACT-G, the KPS, and EOD to determine criterion validity. Test-retest analysis was performed at 1 day and at 1 week. RESULTS The Cronbach alpha coefficients for the MSAS-SF subscales ranged from 0.76 to 0.87. The MSAS-SF subscales showed convergent validity with FACT subscales. Correlation coefficients were -0.74 (P < 0.001) for the PHYS and FACT-G physical well-being subscales, -0.68 (P < 0.001) for the PSYCH and FACT emotional well-being subscales, and -0.70 (P < 0.001) for GDI and FACT summary of quality-of-life subscales. The MSAS-SF subscales demonstrated convergent validity with performance status, inpatient status, and extent of disease. The test-retest correlation coefficients for the MSAS-SF subscales ranged from 0.86 to 0.94 at 1 day and from 0.40 to 0.84 for the 1 week group. CONCLUSIONS The MSAS-SF is a valid and easy to use instrument for symptom assessment.
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Hwang SS, Kim HH, Park SH, Jung JI, Jang HS. The value of CT-guided percutaneous needle aspiration in immunocompromised patients with suspected pulmonary infection. AJR Am J Roentgenol 2000; 175:235-8. [PMID: 10882278 DOI: 10.2214/ajr.175.1.1750235] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE We evaluated the diagnostic efficacy of CT-guided percutaneous needle aspiration in immunocompromised patients with suspected pulmonary infection. SUBJECTS AND METHODS We reviewed the findings and yields of 24 CT-guided percutaneous needle aspirations in 21 immunocompromised patients. Cytologic evaluation and culture for aerobes, anaerobes, Mycobacterium species, and fungus were performed in all aspirates. RESULTS We identified one or more etiologic microorganisms in 19 (79.2%) of 24 CT-guided percutaneous needle aspirations. Of 19 aspirates with positive findings, single causal microorganisms were identified in 18. Staphylococcus aureus was found in four aspirates, and Aspergillus fumigatus in seven; these microorganisms were the principal bacterial (4/11) and fungal (7/9) causative organisms. One of the 19 aspirates with positive findings yielded two microorganisms. In the remaining five aspirates, no microorganisms were identified and cytologic examination revealed nonspecific inflammatory cells. No major complications were observed during or after the procedure. CONCLUSION CT-guided percutaneous needle aspiration is a safe and useful diagnostic method for the identification of specific microorganisms in immunocompromised patients with suspected pulmonary infection.
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Abstract
BACKGROUND The Edmonton Symptom Assessment Scale (ESAS) is a nine-item patient-rated symptom visual analogue scale developed for use in assessing the symptoms of patients receiving palliative care. The purpose of this study was to validate the ESAS in a different population of patients. METHODS In this prospective study, 240 patients with a diagnosis of cancer completed the ESAS, the Memorial Symptom Assessment Scale (MSAS), and the Functional Assessment Cancer Therapy (FACT) survey, and also had their Karnofsky performance status (KPS) assessed. An additional 42 patients participated in a test-retest study. RESULTS The ESAS "distress" score correlated most closely with physical symptom subscales in the FACT and the MSAS and with KPS. The ESAS individual item and summary scores showed good internal consistency and correlated appropriately with corresponding measures from the FACT and MSAS instruments. Individual items between the instruments correlated well. Pain ratings in the ESAS, MSAS, and FACT correlated best with the "worst-pain" item of the Brief Pain Inventory (BPI). Test-retest evaluation showed very good correlation at 2 days and a somewhat smaller but significant correlation at 1 week. A 30-mm visual analogue scale cutoff point did not uniformly distinguish severity of symptoms for different symptoms. CONCLUSIONS For this population, the ESAS was a valid instrument; test-retest validity was better at 2 days than at 1 week. The ESAS "distress" score tends to reflect physical well-being. The use of a 30-mm cutoff point on visual analogue scales to identify severe symptoms may not always apply to symptoms other than pain.
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Hwang SS, Park YH, Kim JY, Jung SL, Ahn MI, Park CK, Chang ED. Primary amyloidoma of the cervical spine. AJNR Am J Neuroradiol 2000; 21:601-3. [PMID: 10730660 PMCID: PMC8174966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Primary solitary amyloidoma of the spine is a disease characterized by localized deposits of amyloid. We describe and illustrate the radiologic appearance of primary solitary amyloidoma of the spine on plain radiographs, CT scans, and MR images. The imaging findings revealed features of a nonspecific soft-tissue mass with calcifications. Epidural extension of the amyloidoma caused spinal cord compression.
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Chang VT, Hwang SS, Feuerman M, Kasimis BS. Symptom and quality of life survey of medical oncology patients at a veterans affairs medical center: a role for symptom assessment. Cancer 2000; 88:1175-83. [PMID: 10699909 DOI: 10.1002/(sici)1097-0142(20000301)88:5<1175::aid-cncr30>3.0.co;2-n] [Citation(s) in RCA: 235] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND The current study was conducted to assess symptom prevalence and symptom intensity and their relation to quality of life in medical oncology patients at a Veterans Affairs medical center. METHODS Consecutive inpatients and outpatients were asked to complete the Functional Assessment Cancer Therapy (FACT-G), Memorial Symptom Assessment Scale (MSAS), and the Brief Pain Inventory. Symptoms then were analyzed by their relation to Karnofsky performance status (KPS) and quality of life. RESULTS Two hundred forty patients participated. The median number of symptoms was 8 per patient (range, 0-30 symptoms). The 5 most prevalent symptoms were lack of energy (62%), pain (59%), dry mouth (54%), shortness of breath (50%), and difficulty sleeping (45%). Patients with moderate intensity pain had a median number of 11 symptoms and patients with moderate intensity lack of energy had a median number of 13 symptoms. The number of intense symptoms increased as the KPS decreased (P < 0.001). Patients with moderately intense pain or fatigue also were more likely to experience nausea, dyspnea, and lack of appetite. The number of symptoms rated as present on the MSAS was found to correlate significantly with the FACT-G Sum Quality of Life score. CONCLUSIONS Intense symptoms were highly prevalent in this population. The presence of pain, lack of energy, or poor performance status should lead to comprehensive symptom assessment. Patients free of disease nevertheless still may experience intense symptoms. The number of symptoms present may be a helpful guide to quality of life. Routine comprehensive symptom assessment may identify a significant fraction of patients who urgently require intensive symptom palliation.
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Lindquist C, Cockerham WC, Hwang SS. Drinking patterns in the American Deep South. JOURNAL OF STUDIES ON ALCOHOL 1999; 60:663-6. [PMID: 10487736 DOI: 10.15288/jsa.1999.60.663] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To determine whether the states of the Deep South are characterized by contradictory drinking norms: high abstinence paired with high consumption among drinkers. METHOD Comparison of survey results of drinking patterns (N = 65,216) in four states of the Deep South (Alabama, Georgia, Louisiana and Mississippi) to those in leading states in the East (New York), Midwest (Illinois), Rocky Mountains (Colorado) and West (California) for the years 1990-93. Respondents were selected by random-digit dialing and interviewed by telephone as part of a larger study conducted by the Behavioral Risk Factor Surveillance System (BRFSS) of the Centers for Disease Control and Prevention (CDC). RESULTS A higher proportion of persons drank alcohol in 1993 than in any of the previous 3 years. Persons with higher education, with higher income, of younger age, male, white and not living in the Deep South were more likely to drink. Among drinkers, the likelihood of episodic heavy drinking decreased with higher education, income and age. In addition, women, blacks and married respondents were less likely to report heavy drinking. Region of residence is not significantly associated with episodic heavy drinking. CONCLUSIONS The Deep South has a significantly higher proportion of abstainers from alcohol use than other regions. Among drinkers, Southerners are not more likely to engage in occasions of heavy drinking. The results are discussed in relation to Southern culture and drinking norms.
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Gupta SK, Shah JC, Hwang SS. Pharmacokinetic and pharmacodynamic characterization of OROS and immediate-release amitriptyline. Br J Clin Pharmacol 1999; 48:71-8. [PMID: 10383563 PMCID: PMC2014871 DOI: 10.1046/j.1365-2125.1999.00973.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To characterize the pharmacokinetics of amitriptyline and its metabolite nortriptyline following OROS and IR treatments, and to correlate them with anticholinergic side-effects. METHODS The pharmacokinetics and safety of amitriptyline following administration of an osmotic controlled release tablet (OROS and an immediate release (IR) tablet were evaluated in 14 healthy subjects. In this randomized, open label, three-way crossover feasibility study, the subjects received a single 75 mg OROS tablet, three 25 mg IR tablets administered every 8 h, or 3x25 mg IR tablets administered at nighttime. In each treatment arm serial blood samples were collected for a period of 84 h after dosing. The plasma samples were analysed by gas chromatography for amitriptyline and its metabolite nortriptyline. Anticholinergic effects such as saliva output, visual acuity, and subject-rated drowsiness and dry mouth were measured on a continuous scale during each treatment period. RESULTS Following dosing with OROS (amitriptyline hydrochloride), the mean maximal plasma amitriptyline concentration Cmax (15.3 ng ml-1 ) was lower and the mean tmax (25.7 h) was longer than that associated with the equivalent IR dose administered at nighttime (26.8 ng ml-1 and 6.3 h, respectively). The bioavailability of amitriptyline following OROS dosing was 95% relative to IR every 8 h dosing, and 89% relative to IR nighttime dosing. The metabolite-to-drug ratios after the three treatment periods were similar, suggesting no change in metabolism between treatments. The relationships between plasma amitriptyline concentration and anticholinergic effects (e.g. reduced saliva weight, dry mouth, and drowsiness) were similar with all three treatments. Of the anticholinergic effects, only decreased saliva weight and dry mouth correlated well with plasma amitriptyline concentrations; drowsiness did not. There was no apparent correlation between anticholinergic effects and the plasma nortriptyline concentration. CONCLUSIONS The bioavailability of OROS (amitriptyline hydrochloride) was similar to that of the IR treatments and the pharmacokinetics of amitriptyline after OROS dosing may decrease the incidence of anticholinergic effects compared with that seen with nighttime dosing of the IR formulation. Therefore, this controlled-release formulation of amitriptyline may be appropriate for single daily administration.
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Subotnik KL, Nuechterlein KH, Ventura J, Green MF, Hwang SS. Prediction of the deficit syndrome from initial deficit symptoms in the early course of schizophrenia. Psychiatry Res 1998; 80:53-9. [PMID: 9727963 DOI: 10.1016/s0165-1781(98)00052-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The Proxy for the Deficit Syndrome (PDS) was used with longitudinal symptom assessment data to identify recent-onset schizophrenia patients with the deficit syndrome. We evaluated the stability of deficit symptoms using repeated assessments. Symptom ratings were examined at an initial point of outpatient stabilization on antipsychotic medication as well as prospectively over the subsequent 12 months of outpatient treatment and assessment in 83 recent-onset schizophrenia patients. The vast majority of patients who were classified as non-deficit at the cross-sectional baseline assessment continued to remain non-deficit throughout the first year of treatment. However, patients classified as deficit at baseline did not consistently remain classified as showing deficit syndrome during the follow-through period. Thus, the presence of deficit symptoms detected in a single cross-sectional rating may be an inaccurate way to rate the deficit syndrome, yielding excessive false positives. Our use of longitudinal data allowed the stability criterion of the deficit syndrome to be evaluated using the PDS.
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Yu Z, Gupta SK, Hwang SS, Kipnes MS, Mooradian AD, Snyder PJ, Atkinson LE. Testosterone pharmacokinetics after application of an investigational transdermal system in hypogonadal men. J Clin Pharmacol 1997; 37:1139-45. [PMID: 9506009 DOI: 10.1002/j.1552-4604.1997.tb04298.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This open-label, randomized, placebo lead-in, three-treatment crossover study in 19 hypogonadal men (27-82 years of age) evaluated dose proportionality of serum testosterone concentrations with application of one or two investigational transdermal testosterone systems for application to the arm or torso. Testosterone in vivo kinetics profiles were determined using DeMonS, a recently developed numerical deconvolution method that estimates drug absorption at different time intervals and/or drug disposition model parameters. After application of the investigational transdermal systems, the mean serum testosterone, dihydrotestosterone, estradiol, and free testosterone concentrations were elevated to normal levels. Treatment allowed approximation of the normal circadian pattern of endogenous testosterone secretion, and the increase in serum testosterone concentrations was proportional to the surface area of systems applied. The investigational transdermal system provided effective testosterone replacement therapy as judged by pharmacokinetic parameters.
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Yu Z, Gupta SK, Hwang SS, Cook DM, Duckett MJ, Atkinson LE. Transdermal testosterone administration in hypogonadal men: comparison of pharmacokinetics at different sites of application and at the first and fifth days of application. J Clin Pharmacol 1997; 37:1129-38. [PMID: 9506008 DOI: 10.1002/j.1552-4604.1997.tb04297.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this study of 13 hypogonadal men (25-69 years of age), three open-label, randomized treatments were administered to determine the pharmacokinetics of serum testosterone after application of an investigational testosterone transdermal system to the upper buttocks, upper arm, and back. Testosterone in vivo input kinetics profiles were estimated by DeMonS, a recently developed numerical deconvolution method for estimating drug absorption at different time intervals and/or drug disposition model parameters, and compared on the first and fifth days of system application. Area under the concentration-time curve from 0 to 27 hours (AUC0-27) values for testosterone after one-day applications to the upper buttocks, upper arm, and back were 9,560 ng.hr/dL, 8,651 ng.hr/dL, and 8,988 ng.hr/dL, respectively. Maximum observed concentration (Cmax) values were 482 ng/dL, 462 ng/dL, and 499 ng/dL, respectively. Serum testosterone concentrations were equivalent to each other, and Cmax values fell within the normal range. No drug accumulation was seen with repeated dosing over 5 days.
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Kim HH, Shin YR, Kim KJ, Hwang SS, Ha HK, Byun JY, Choi KH, Shinn KS. Blunt traumatic rupture of the diaphragm: sonographic diagnosis. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 1997; 16:593-598. [PMID: 9321778 DOI: 10.7863/jum.1997.16.9.593] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ultrasonographic features of seven patients with diaphragmatic rupture due to blunt trauma were analyzed. The ruptures occurred at the left hemidiaphragm in four patients and at the right in three. Direct ultrasonographic findings were as follows: disrupted diaphragm in four patients; nonvisualized diaphragm in three patients; floating diaphragm in two patients; and herniation of the liver or bowel loops through the diaphragmatic defect in three patients. Indirect sonographic findings included pleural effusion or subphrenic fluid collection in five patients and splenic laceration in one. Although the number of patients was limited, ultrasonography was very useful for the diagnosis of diaphragmatic rupture.
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Yu Z, Hwang SS, Gupta SK. DeMonS--a new deconvolution method for estimating drug absorbed at different time intervals and/or drug disposition model parameters using a monotonic cubic spline. Biopharm Drug Dispos 1997; 18:475-87. [PMID: 9267681 DOI: 10.1002/(sici)1099-081x(199708)18:6<475::aid-bdd33>3.0.co;2-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DeMonS-a new numerical deconvolution method for estimating the amount of drug absorbed at different time intervals and/or drug disposition model parameters-is presented here. In DeMonS, the amount of drug absorbed at different time intervals and/or drug disposition model parameters are the unknown parameters to be calculated. The Fritsch-Butland non-decreasing cubic spline was constructed from the cumulative amount of drug absorbed-time data directly derived from the calculated amount of drug absorbed at different time intervals. The drug absorption rate, which is the derivative of this non-decreasing cubic spline, is therefore represented by a piecewise non-negative quadratic function. The drug concentrations were obtained by convoluting the drug absorption rate quadratic function with the drug disposition model function. The nonlinear optimization method with simple parameter bounds was used to estimate the optimal set of unknown parameters by minimizing the sum of squares of residuals between the observed and predicted drug concentrations. DeMonS has been applied to (i) the griseofulvin data for estimating drug absorbed at different time intervals when the drug disposition model parameters were determined separately from intravenous data, (ii) veralipride double-peak phenomenon data to estimate simultaneously the percentage of cumulative veralipride absorbed and the veralipride disposition model parameters without reference intravenous data, (iii) a comparative bioequivalence study of gastrointestinal therapeutic system (GITS) pseudoephedrine HCI (PeHCI) controlled-release oral dosage forms when the drug disposition model parameters were not available, and (iv) estimation of both drug disposition model parameters and the absorption rate of drug from Testoderm (testosterone transdermal system) in the presence of endogenous testosterone production. DeMonS was implemented using MATLAB and NAG MATLAB Toolbox, and is available for Windows 3.1.
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Gupta SK, Hwang SS, Causey D, Rolf CN, Gorsline J. Comparison of the nicotine pharmacokinetics of Nicoderm (nicotine transdermal system) and half-hourly cigarette smoking. J Clin Pharmacol 1995; 35:985-9. [PMID: 8568016 DOI: 10.1002/j.1552-4604.1995.tb04014.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Nicoderm, a nicotine transdermal system (NTS), provides a continuous, transdermal delivery of nicotine and is used as an aid to smoking cessation. In contrast, cigarette smoking yields nicotine concentrations in plasma that rise and fall with each cigarette. The primary objective of this study was to compare nicotine pharmacokinetics after treatment of subjects with either the NTS or controlled smoking. Fourteen healthy adult male smokers, who smoked at least 30 cigarettes per day, were entered into a randomized crossover design trial that compared the NTS, 21 mg/day applied for 24 hours, with half-hourly smoking during the day. Subjects abstained from smoking for 2 days, and were treated for 5 days with either the NTS (daily) or controlled smoking (30 cigarettes at half-hourly intervals on days 1 and 5; ad libitum smoking on days 2-4). Blood samples were obtained frequently on days 1 and 5 for analysis of nicotine and cotinine. Pharmacokinetic comparisons showed that nicotine Cmax, area under the curve (AUC)inf, and Cavg for the NTS were lower than corresponding values for controlled smoking; Cmax and Cavg values were approximately half those of smoking. Cmax and Cavg values for cotinine were similarly lower for the NTS compared to controlled smoking. For both treatments, plasma nicotine concentrations were higher on day 5 compared to day 1. Thus, the NTS provides concentrations of nicotine that are lower than smoking.
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Hwang SS, Gorsline J, Louie J, Dye D, Guinta D, Hamel L. In vitro and in vivo evaluation of a once-daily controlled-release pseudoephedrine product. J Clin Pharmacol 1995; 35:259-67. [PMID: 7608314 DOI: 10.1002/j.1552-4604.1995.tb04056.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The functionality of a once-daily, osmotic dosage form--gastrointestinal therapeutic system (pseudoephedrine HCl) or GITS (PeHCl)--was studied in vitro and in vivo. The in vitro release profiles were close to identical from pH 1 to 7.5 and between USP apparatus 2 and 7, independent of paddle speeds from 50 to 200 rpm; GITS also released drug at the normal rate in aqueous media after incubation in bile salts or fatty media. Both strengths of GITS (PeHCl)--240 and 120 mg--were then compared with a commercially available pseudoephedrine solution given every 6 hours and a timed-release 12-hour pseudoephedrine capsule given every 12 hours in a randomized 4-way crossover study in 24 healthy men. All four formulations were equivalent in total drug absorbed. Both GITS treatments had AUCinf values equivalent to those of PeHCl solution and capsules, and Cmax values equivalent to PeHCl capsules. Cmax for GITS and capsule treatments were each significantly lower than for solution, but the differences were small (14-17%). A one-to-one correlation was shown between rate of absorption and in vitro release profiles for the GITS products, indicating that drug release from GITS controls absorption. Insensitivity to conditions of in vivo release accounts for the close in vitro/in vivo correlation of release rates. In a second randomized crossover trial (12 men), the effect of a high-fat breakfast on GITS performance was evaluated. Mean pseudoephedrine concentrations in plasma were close to identical with or without the breakfast, and the treatments were bioequivalent.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
Drug disposition kinetics are commonly assumed to be time-invariant as a first approximation. In a preliminary study, 6 healthy volunteers received a constant intravenous infusion of 50 micrograms/h for 48 hours; the serum fentanyl concentration at 36 hours was lower than that at 24 hours for all 6 subjects. This suggested possible diurnal variations in fentanyl clearance. In 2 subsequent studies, with healthy volunteers receiving short infusions of fentanyl (n = 9, 150 micrograms/h for 0.33 hours every 4 hours; n = 12, 150 micrograms/h for 0.33 hours every hour, respectively), the area under the serum fentanyl concentration curve appeared to be independent of the time of infusion. Thus, there was no evidence to support a large diurnal change in fentanyl clearance. The serum fentanyl concentration-time profiles, corrected for carryover from previous doses, within each study were superimposable. This suggests that there are no diurnal changes in the distribution kinetics of fentanyl.
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Knowles M, Hwang SS. The influence of the shape of the plasma drug concentration profile upon the pharmacological effect. Pharm Res 1995; 12:168-70. [PMID: 7724482 DOI: 10.1023/a:1016223712041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Saenz R, Hwang SS, Aguirre BE. In search of Asian war brides. Demography 1994; 31:549-59. [PMID: 7828771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Because of the long presence of U.S. soldiers in Asia, war-bride marriages involving servicemen and Asian women have been formed throughout the century. The literature, however, contains little empirically sound information on Asian war brides. This analysis develops a methodology to identify war brides and applies it to estimate the number of war brides from the six major Asian groups, using the national 1980 Public Use Microdata Sample. Further analysis comparing Asian war brides with other groups of Asian wives tends to support the traditional and lower socioeconomic images commonly associated with Asian war brides.
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Park SH, Song HH, Han JH, Park JM, Lee EJ, Park SM, Kang KJ, Lee JH, Hwang SS, Rho SC. Effect of noise on the detection of rib fractures by residents. Invest Radiol 1994; 29:54-8. [PMID: 8144338 DOI: 10.1097/00004424-199401000-00009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
RATIONALE AND OBJECTIVES The authors assessed the effect of noise on the detectability of rib fractures by residents. METHODS Eight radiology residents read chest posterior-anterior radiographs of 92 subjects with rib fracture(s) and 28 normal subjects to detect rib fracture(s) according to a five-point scale of confidence, under quiet and "noisy" conditions. Each individual's attitude toward noise was measured by a multiple-choice questionnaire. RESULTS The readers were divided into two groups depending on the questionnaire result: group A readers were accustomed to a quiet environment, and group B readers were accustomed to noisy environments or were unaffected by noise. Group A's performance, measured by the area (Az) under the receiver operating characteristic (ROC) curve, was better in quiet conditions when compared with their performance in noisy conditions; however, the opposite tendency was observed for group B. There was a significant individual difference of performance in response to noise. CONCLUSION Effect of noise on the detection of rib fractures depends on an individual's attitude toward sound and noise.
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Abstract
A theoretical investigation has been conducted to understand the deconvolution method used for evaluating the in vivo release rate of an oral controlled-release product from the plasma drug concentration versus time profile. The theory is based on well-accepted pharmacokinetic compartmental models. The cumulative amount of drug released from a dosage form can be partitioned into two parts: the amount already absorbed and the amount released but still remaining at the absorption site in the gastrointestinal tract. The cumulative amount absorbed at any time, t, can be estimated from the plasma concentration versus time profile by the compartmental model-based Wagner-Nelson method or Loo-Riegelman method. We have derived a mathematical expression relating the amount at the absorption site with the plasma drug concentration versus time profile assuming a first-order absorption rate process. The difference between the in vivo release profile and the in vivo absorption profile is illustrated. Because what determined in vitro is the release profile, it should preferentially be correlated with the in vivo release profile, not the absorption profile. However, when absorption is much faster than elimination, the estimated absorption profile is a good approximation of the release profile. In this circumstance, it is advantageous to use absorption profiles to demonstrate correlation of in vitro and in vivo dosage form performance to avoid the noise inherent in the numerical method of deriving the exact in vivo release profile.
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Gupta SK, Hwang SS, Benet LZ, Gumbleton M. Interpretation and utilization of effect and concentration data collected in an in vivo pharmacokinetic and in vitro pharmacodynamic study. Pharm Res 1993; 10:889-94. [PMID: 8321858 DOI: 10.1023/a:1018969429535] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The effect (E) of some drugs may be monitored in vitro using the plasma drug concentration (C) following the in vivo dosing of drug. When using a specific analytical assay, counterclockwise hysteresis in the E vs C relationship can be explained only by the presence of an agonistic metabolite (MA); the extent of hysteresis will depend upon the pharmacokinetics and relative "potency" of C and MA. If a nonspecific assay is used, plots of E vs C may actually relate to E vs total agonist (C + MA), and unusual hysteresis may be observed, e.g., clockwise hysteresis when C is more "potent" than MA. Here, we simulate data for three models of relative C and MA pharmacokinetics. The E vs C and E vs MA data are simulated for both linear and noncompetitive agonist Emax models. When C and MA are equally potent, hysteresis will not be observed in a plot of E vs C + MA. However, when C and MA are of differing "potencies," hysteresis will be observed (the direction of hysteresis is dependent on the relative potency of C and MA). By appropriately "weighting" a respective agonist (C or MA), hysteresis will "collapse" and the relative potencies of C and MA can be estimated.
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Mintz J, Mintz LI, Arruda MJ, Hwang SS. Treatments of depression and the functional capacity to work. ARCHIVES OF GENERAL PSYCHIATRY 1992; 49:761-8. [PMID: 1417427 DOI: 10.1001/archpsyc.1992.01820100005001] [Citation(s) in RCA: 307] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This study evaluated the effects of antidepressants and psychotherapy on work impairment in depressed patients. Original databases from 10 published treatment studies were compiled and analyzed (N = 827). Functional work impairment was common at baseline, manifested by unemployment (11%) or on-the-job performance problems (absenteeism, decreased productivity, interpersonal problems, 44%). Generally, work outcomes were good when treatment was symptomatically effective, but the trajectories of work restoration and symptom remission were different, with work recovery appearing to take considerably longer. Relapse was an important determinant of long-term occupational outcome, particularly for seriously ill patients for whom relapse meant rehospitalization or other profound social disruption. Affective impairment was distinguished from functional impairment, with the former characterizing milder depression and the latter characterizing moderate to severe depression. Some methodological recommendations are discussed.
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Giachetti C, Hwang SS, Semler BL. cis-acting lesions targeted to the hydrophobic domain of a poliovirus membrane protein involved in RNA replication. J Virol 1992; 66:6045-57. [PMID: 1326655 PMCID: PMC241482 DOI: 10.1128/jvi.66.10.6045-6057.1992] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The structural requirements of the hydrophobic domain contained in poliovirus polypeptide 3AB were studied by using a molecular genetic approach in combination with an in vitro biochemical analysis. We report here the generation and analysis of deletion, insertion, and amino acid replacement mutations aimed at decreasing the hydrophobic character of the domain. Our results indicated that the hydrophobicity of this region of 3AB is necessary to maintain normal viral RNA synthesis. However, in vitro membrane association assays of the mutated proteins did not establish a direct correlation between 3AB membrane association and viral RNA synthesis. Some of the lethal mutations we engineered produced polyproteins with abnormal P2- and P3-processing capabilities due to an alteration in the normal cleavage order of the polyprotein. A detailed analysis of these mutants suggests that P2 is not the major precursor for polypeptides 2A and 2BC and that P2 protein products are derived from P2-P3-containing precursors (most likely P2-P3 or P2-3AB). Such precursors are likely to result from primary polyprotein cleavage events that initiate a proteolytic cascade not previously documented. Our results also indicated that the function provided by the hydrophobic domain of 3AB cannot be provided in trans. We discuss the implications of these results on the formation of limited-diffusion replication complexes as a means of sequestering P2- and P3-region polypeptides required for RNA synthesis and protein processing.
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Hwang SS, Boyle TJ, Lyerly HK, Cullen BR. Identification of envelope V3 loop as the major determinant of CD4 neutralization sensitivity of HIV-1. Science 1992; 257:535-7. [PMID: 1636088 DOI: 10.1126/science.1636088] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Laboratory isolates of human immunodeficiency virus type-1 (HIV-1) such as HTLV-IIIB are generally T cell line-tropic and highly sensitive to neutralization by soluble CD4 (sCD4), a potential antiviral agent that is undergoing clinical trial. However, many primary HIV-1 isolates are macrophage-tropic and sCD4-resistant. Envelope V3 loop sequences derived from primary HIV-1 isolates were sufficient to confer on HTLV-IIIB not only the tissue tropism but also the degree of sCD4 neutralization resistance characteristic of their HIV-1 strains of origin. Single amino acid changes in the V3 loop enhanced sCD4 resistance by up to tenfold. These observations suggest that the tissue tropism and sCD4 neutralization sensitivity of HIV-1 isolates are regulated by similar mechanisms.
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Gorsline J, Okerholm RA, Rolf CN, Moos CD, Hwang SS. Comparison of plasma nicotine concentrations after application of nicoderm (nicotine transdermal system) to different skin sites. J Clin Pharmacol 1992; 32:576-81. [PMID: 1634647 DOI: 10.1177/009127009203200615] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Drug absorption through the skin can vary according to the application site. The nicotine transdermal system, Nicoderm (Alza Corp., Palo Alto, CA) contains a rate-controlling membrane designed to regulate delivery of nicotine to the skin and thus limit variability in nicotine plasma levels. Plasma nicotine concentrations were compared after application of NTS 14 mg/day to three different skin sites (upper back, upper outer arm, upper chest) in a randomized, crossover study involving 12 healthy male smokers. Plasma nicotine profiles from all three sites were similar: nicotine concentrations increased rapidly within 2 to 4 hours, reached broad peaks of approximately 11 to 14 ng/mL, and then remained relatively constant between 8 and 24 hours after application. The mean nicotine maximum peak plasma concentration values for nicotine transdermal system application to the arm, back, and chest were equivalent (13.8, 14.6, and 13.2 ng/mL, respectively). The mean time to reach peak concentration (tmax) (3 to 6 hours), and area under the curve (168, 186, and 183 ng.h/mL) values for the arm, back, and chest, respectively, were not significantly different. Thus, bioequivalent plasma nicotine concentrations were achieved irrespective of the application site on the upper body.
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