Melt processing of polypropylene-grafted-maleic anhydride/Chitosan polymer blend functionalized with montmorillonite for the removal of lead ions from aqueous solutions

Heavy metals such as lead ions Pb (II) are a primary concern in the aquatic environment. These is because Pb (II) is poisonous at a threshold limit above 0.01 mg/L, when consumed over a long period of time. Pb (II) poisoning is very harmful to various organs viz. heart, intestine and kidneys. Besides, it affects bones, tissues, nervous and reproductive systems. Hence, it is important to remove Pb (II) from aquatic environment. Polypropylene (PP) and polypropylene grafted-maleic-anhydride (PP-g-MA) based nanocomposites reinforced with Chitosan (CS) and modified montmorillonite clay nanofiller (CL120DT) were successfully fabricated using twin screw melt extrusion for adsorption of Pb (II). The resulting nanocomposites were characterized by XRD to analyze the dispersion properties of the material, TEM and SEM for surface morphology, FTIR analysis for the functional groups and TGA for thermal stability. Pure PP showed two sharp peaks, but there was decreased in the intensity upon adding of CS and CL120DT. Among series of nanocomposites 2.0 phr and 4.0 phr loaded samples shows better storage module than that of pure PP. The uptake of Pb (II) from lead nitrate aqueous solution by PP + PP-g-MA/CL120DT-CS 2.0 phr nanocomposites followed the Langmuir isotherm model, with a remediation of 90.9% at pH 8 and was verified by pseudo-second order kinetic model. These results indicate that PP + PP-g-MA//CL120DT-CS 2.0 phr nanocomposites performed as a superabsorbent for the Pb (II) ion removal from aqueous solution.

Supine sleep positioning in preterm and term infants after hospital discharge from 2000 to 2011

OBJECTIVE

Supine sleep positioning (SSP) has been shown to reduce the risk of sudden infant death syndrome (SIDS) and preterm infants are at higher risk for SIDS. Population-based estimates of SSP are lacking for the preterm population. The objectives of this study are: (1) compare the prevalence of SSP after hospital discharge for preterm and term infants in the United States; and (2) assess racial/ethnic disparities in SSP for preterm and term infants.

STUDY DESIGN

We analyzed the 2000 to 2011 data from the Pregnancy Risk Assessment Monitoring System of Centers for Disease Control and Prevention from 35 states. We measured prevalence of SSP by preterm and term gestational age (GA) categories. We calculated adjusted prevalence ratios (APR) to evaluate the likelihood of SSP for each GA category compared with term infants and the likelihood of SSP for non-Hispanic black (NHB) and Hispanic infants compared with non-Hispanic white (NHW) infants.

RESULTS

Prevalence of SSP varied by GA: ⩽27, 59.7%; 28 0/7 to 33 6/7, 63.7%; 34 0/7 to 36 6/7 (late preterm), 63.6%; and 37 0/7 to 42 6/7 (term) weeks, 66.8% (P<0.001). In the adjusted analyses, late preterm infants were slightly less likely to be placed in SSP compared with term infants (APR: 0.96, confidence interval: 0.95 to 0.98). There were racial/ethnic disparities in SSP for all GA categories when NHB and Hispanic infants were compared with NHW infants.

CONCLUSIONS

All infants had suboptimal adherence to SSP indicating a continued need to better engage families about SSP. Parents of late preterm infants and families of NHB and Hispanic infants will also require greater attention given their decreased likelihood of SSP.

Tuberculosis is frequently diagnosed within 12 months of diabetes mellitus

BACKGROUND

Evidence regarding the effects of tuberculosis (TB) screening among patients with diabetes mellitus (DM) in intermediate TB burden countries is insufficient, and the most appropriate time point for TB screening is unclear.

OBJECTIVE

To investigate trends in TB incidence among newly diagnosed DM patients.

DESIGN

A retrospective cohort study of the claims database of the Health Insurance Review and Assessment Service in Korea was performed. Participants were newly diagnosed with type 2 DM in 2009. The study outcome was TB incidence between 2009 and 2011 among participants according to duration of type 2 DM.

RESULTS

A cohort of 331,601 patients with newly diagnosed type 2 DM in 2009 was identified. During the 3-year follow-up period, 1533 patients were diagnosed with TB. The estimated incidence of TB among newly diagnosed type 2 DM patients was 18/10,000 patient-years (py) (95%CI 17.5-19.4). TB incidence was 33/10,000 py (95%CI 30.0-35.6) in the first 6 months, and 19/10,000 py (95%CI 16.5-20.6) in the following 6-month period.

CONCLUSIONS

The risk of developing TB was increased among DM patients, particularly during the first 12 months after DM diagnosis.

Implementation of safe sleep practices in the neonatal intensive care unit

OBJECTIVE

To increase the percentage of eligible infants engaging in safe sleep practices (SSP) in two level III neonatal intensive care units (NICUs) in the Boston, Massachusetts area.

STUDY DESIGN

On the basis of eligibility criteria (⩾34 weeks or ⩾1800 g without acute medical conditions), all infants were eligible for two sleep practices: SSP or NICU therapeutic positioning (NTP) depending on their gestational age, weight, clinical illness and need for therapeutic interventions. Compliance with SSP was defined as: (1) supine positioning, (2) in a flat crib with no incline, (3) without positioning devices and (4) without toys, comforters or fluffy blankets. NTP comprised usual NICU care. Nursing education was comprised of a web-based learning module and in-person teaching sessions with a study team member. Double-sided crib cards (SSP one side and NTP on the other) were attached to the bedside of every infant. Pre- and postintervention audits of all infants were carried out at both study sites. We compared compliance across all time points using generalized estimating equations to account for correlated data (SAS v9.3, Cary, NC, USA).

RESULT

Of 755 cases, 395 (52.3%) were assessed to be eligible for SSP. From the pre- to post-intervention period, there was a significant improvement in overall compliance with SSP (25.9 to 79.7%; P-value<0.001). Adherence to each component of SSP also improved significantly following the intervention.

CONCLUSION

Safe infant sleep practices can be integrated into the routine care of preterm infants in the NICU. Modeling SSP to families far in advance of hospital discharge may improve adherence to SSP at home and reduce the risk of sleep-related morbidity and mortality in this vulnerable population of infants.

The effects of statin use on the development of tuberculosis among patients with diabetes mellitus

OBJECTIVE

To evaluate whether statin use affects the development of tuberculosis (TB) among patients with diabetes mellitus (DM).

METHODS

This is a retrospective cohort study of patients with newly diagnosed type 2 DM based on the South Korean nationwide claims database. The participants were type 2 DM patients aged 20-99 years who were newly treated with anti-diabetic drugs between 1 January 2007 and 31 December 2010. Patients who had statin prescriptions before a diagnosis of diabetes or were diagnosed with TB before diabetes were excluded.

RESULTS

Of 840,899 newly diagnosed type 2 DM patients, 281,842 (33.5%) patients were statin users and 559,057 (66.5%) were non-users. During the study period, 4075 [corrected] individuals were diagnosed with TB; the estimated incidence of TB in our cohort was 251/100,000 patient-years (95%CI 243-258). In comparison to non-TB patients, statin users were less frequent among TB patients (19.2% vs. 33.6%). After adjustment for potential baseline confounders, statin use was not associated with the development of TB in DM patients (aHR 0.98; 95%CI 0.89-1.07).

CONCLUSIONS

TB development among newly diagnosed type 2 DM was considerable, and statin use among these diabetics was not associated with a protective effect on TB incidence.

Impact of intra-abdominal fat on surgical outcome and overall survival of patients with gastric cancer

BACKGROUND

The aim of this study was to evaluate the impact of obesity on surgical outcome and prognosis in patients with gastric cancer.

METHODS

A total of 304 patients who underwent curative gastrectomy for gastric adenocarcinoma between January 2005 and March 2008were enrolled. Body mass index (BMI) was calculated before the operation and visceral fat area (VFA) was measured by abdominal computed tomography (CT). The patients were divided according to BMI class and VFA quartile. The influence of BMI and VFA on surgical outcome and survival was evaluated.

RESULTS

The median BMI was 23.3 kg/m(2) and the median VFA was 103 cm(2). There was a significant positive correlation between BMI and VFA. According to BMI class and VFA quartile, there were no significant differences in patients' characteristics or surgical outcome, with the exception of a significantly longer operation time and fewer retrieved lymph nodes in patients with a high BMI and VFA. The unadjusted overall and disease free survival were not significantly different between BMI classes or VFA quartiles.

CONCLUSIONS

Obesity, as represented by BMI and VFA, may not be a poor prognostic factor in patients with gastric cancer.

Neonatal intensive care unit discharge preparation, family readiness and infant outcomes: connecting the dots

Neonatal intensive care unit (NICU) discharge readiness is defined as the masterful attainment of technical skills and knowledge, emotional comfort, and confidence with infant care by the primary caregivers at the time of discharge. NICU discharge preparation is the process of facilitating comfort and confidence as well as the acquisition of knowledge and skills to successfully make the transition from the NICU to home. In this paper, we first review the literature about discharge readiness as it relates to the NICU population. Understanding that discharge readiness is achieved, in part, through successful discharge preparation, we then outline an approach to NICU discharge preparation.

Diagnostic accuracy of Xpert® MTB/RIF on bronchoscopy specimens in patients with suspected pulmonary tuberculosis

OBJECTIVE

To determine the diagnostic accuracy of the Xpert® MTB/RIF assay using samples obtained through bronchoscopy in patients with suspected pulmonary tuberculosis (PTB).

DESIGN

We retrospectively reviewed the records of patients with suspected PTB for whom the Xpert MTB/RIF assay was performed on bronchoscopy specimens. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the diagnosis of active PTB were calculated for acid-fast bacilli (AFB) smear microscopy and the Xpert assay using culture of Mycobacterium tuberculosis from sputum or bronchoscopy specimens as a reference standard.

RESULTS

A total of 132 patients were included in the final analysis. Of these, 38 had culture-confirmed PTB. The sensitivity of the Xpert assay using bronchial washing or bronchoalveolar lavage (BAL) fluid for the diagnosis of PTB was 81.6%, and specificity was 100%. The PPV and NPV were 100% and 92.1%, respectively. The sensitivity and specificity of AFB smear microscopy were respectively 13.2% and 98.8%.

CONCLUSION

The Xpert assay on bronchoscopy specimens provided an accurate diagnosis of PTB in patients who had a negative AFB smear or who could not produce sputum.

The impact of combined pulmonary fibrosis and emphysema on mortality

SETTING

The impact on patient mortality of combined pulmonary fibrosis and emphysema (CPFE) compared with emphysema alone has never been investigated.

OBJECTIVE

To elucidate whether CPFE has an impact on overall mortality over that of emphysema alone.

DESIGN

We screened patients who underwent chest computed tomography (CT) scans during the period from 1 January 2001 to 31 December 2005 in a tertiary referral hospital. Patients who had both emphysema and pulmonary fibrosis, thus meeting the inclusion criteria, were defined as CPFE. Controls with emphysema alone who were matched for age, sex and the date of CT scan were randomly selected. Cox proportional regression analysis was performed to verify whether CPFE is associated with increased overall mortality.

RESULTS

We found 135 CPFE cases. In the multivariable Cox regression stratified by the presence of comorbid malignancy, CPFE had five times higher mortality risk (adjusted HR 5.10, 95%CI 1.75-14.9) in non-malignant cases, and showed a statistically insignificant trend for higher mortality risk (adjusted HR 1.70, 95%CI 0.94-2.51) in the malignant cases after adjusting for forced vital capacity, height and hypertension.

CONCLUSION

CPFE is not rare and CPFE patients had a higher overall mortality risk than emphysema-only patients.

Association of the interferon-γ gene (CA)n repeat polymorphism with endometriosis

OBJECTIVE

To investigate whether the interferon-γ (IFN-γ) gene (CA)(n) repeat polymorphism is associated with susceptibility to endometriosis.

DESIGN

Case-control study.

SETTING

University Department of Obstetrics and Gynaecology.

POPULATION

Women with (n = 622) and without (n = 442) endometriosis.

METHODS

Genotyping was performed by fluorescent polymerase chain reaction (PCR) and gene-scan analysis.

MAIN OUTCOME MEASURES

Genotype distribution and allele frequency of the dinucleotide (CA)(n) repeat polymorphism in the IFN-γ gene.

RESULTS

Seven alleles (12-18 repeats) of the IFN-γ gene (CA)(n) repeat polymorphism were found. In both patients with endometriosis and controls the most common allele was composed of 13 repeats, followed by an allele of 15 repeats, and then by an allele of 12 repeats. Patients with endometriosis had a significantly higher incidence of genotypes with alleles composed of fewer repeats (12-13 repeats), compared with the controls (92.0 versus 84.4%, respectively, P < 001).

CONCLUSIONS

Our results suggest that the (CA)(n) repeat polymorphism in the IFN-γ gene may be associated with a risk of endometriosis in the South Korean population.

Socio-economic disparities in behavioural risk factors for cancer and use of cancer screening services in Korean adults aged 30 years and older: the Third Korean National Health and Nutrition Examination Survey, 2005 (KNHANES III)

OBJECTIVES

To estimate the current status of cancer-related health disparities in cancer risk factors and the use of cancer screening services by Korean adults.

STUDY DESIGN

Cross-sectional survey study.

METHODS

The disparities of behavioural cancer risk factors and use of cancer screening services according to equivalent monthly household income were evaluated, using multivariate logistic regression analysis, among 6466 subjects aged ≥30 years and who completed the health promotion knowledge, attitude and practice survey, which is part of the Third Korean National Health and Nutrition Examination Survey.

RESULTS

In men, smoking (P for trend = 0.05) and physical inactivity (P for trend = 0.05) were more common in the lower-income group, while high-risk drinking (P for trend <0.01) was more common in the higher-income group. In women, physical inactivity (P for trend <0.01) was more common in the lower-income group, while smoking and high-risk drinking showed no income disparities. Income disparities were also found in the degree of participation in cancer screening programmes. Men in the highest income quintile underwent more screening for both colorectal and gastric cancer than men in the lowest income quintile and men in the second to fourth income quintiles (P for trend <0.01 for both). Women in the highest income quintile underwent more screening for cervical (P for trend <0.01) and gastric (P for trend = 0.04) cancer, while income disparities were not seen for participation in colorectal or breast cancer screening.

CONCLUSIONS

In order to decrease behavioural risk factors and promote participation in cancer screening programmes, more targeted efforts are needed for cancer prevention among lower-income Koreans.

The CT and F-FDG PET/CT appearance of primary renal malignant fibrous histiocytoma

Renal malignant fibrous histiocytoma (MFH) is a rare, primary renal tumour. Imaging findings of renal MFH, including ultrasound, CT and MRI, have, however, been reported. As to the best of our knowledge (18)F-FDG PET/CT imaging of renal MFH has not been previously reported, we present the CT and (18)F-FDG PET/CT appearance of a pathologically proven primary renal MFH.

Risk factors for multidrug-resistant bacterial infection among patients with tuberculosis

Given that anti-tuberculosis medication itself has antibacterial activity and that broad-spectrum antibiotics are frequently used, the emergence of multidrug-resistant (MDR) bacteria among patients being treated for tuberculosis (TB) is likely. We used a case-control design to study the clinical predictors of MDR bacterial infection among TB patients. Both cases and controls were selected from among patients who were diagnosed and treated as having TB between 1 January 1996 and 31 August 2006. TB patients with MDR bacterial infection were included as cases and those with non-MDR bacterial infection were included as controls. Multiple logistic regression analysis was performed to elucidate the risk factors for MDR bacterial infection. During the study period 3667 patients were diagnosed with, and treated for, TB. A total of 123 experienced episodes of bacterial infection, of whom 59 (48.0%) were infected by an MDR strain at least once. The presence of chronic renal failure [adjusted odds ratio (OR): 4.96; 95% confidence interval (CI): 1.37-18.01] and the use of antimicrobials other than typical anti-TB drugs within three months (adjusted OR: 4.37; 95% CI: 1.74-10.95) were independent risk factors for MDR bacterial infection. Bacterial infection in TB patients is commonly multidrug resistant. Clinicians should be aware of the possibility of MDR bacterial infection among TB patients with chronic renal failure or recent use of other antimicrobials.

Metanephric adenoma of the kidney

Metanephric adenoma is an extremely rare, epithelial, renal tumor with characteristic histology. This tumor is invariably benign. We report a case of metanephric adenoma diagnosed by ultrasound-guided needle biopsy.

N-butyl-2-cyanoacrylate pulmonary embolism after endoscopic injection sclerotherapy for gastric variceal bleeding

PURPOSE

The purpose of this work was to describe the radiologic and clinical manifestations of n-butyl-2-cyanoacrylate pulmonary embolism (PE) after endoscopic injection sclerotherapy (EIS) for gastric variceal bleeding.

METHOD

From 1992 to 1999, the medical records of 140 patients who had undergone EIS using n-butyl-2-cyanoacrylate were reviewed for identification of respiratory symptoms and amount of injection, and their pre- and postprocedure chest radiographs were reviewed to identify PE. In patients with PE, pre- and postprocedure chest radiographs (6/6), chest CT scans (3/6), lung perfusion scans (3/6), and follow-up chest radiographs (6/6) were analyzed retrospectively.

RESULTS

Radiographically evident PE was observed in 6 (4.3%) of 140 patients. In comparison with patients without emboli, these patients received a higher mean volume of injection (4.2 vs. 1.8 ml) (p = 0.0011). Four of the six patients with pulmonary emboli had respiratory symptoms. Chest radiographs and CT scans showed unusual tubular or nodular, radiopaque pulmonary emboli along the pulmonary vessels. Multiple peripheral, wedge-shaped, subsegmental perfusion defects were seen on perfusion lung scans. In five of six patients, the radiographic abnormalities showed complete or partial resolution. There were no fatalities directly associated with PE.

CONCLUSION

Radiographically evident PEs are uncommonly observed following EIS and appear to be more common in patients receiving a higher volume of liquid acrylate. Affected patients were either mildly symptomatic or asymptomatic, and there were no direct fatalities of this complication.

Spontaneous rupture of hydronephrotic kidney during pregnancy: value of serial sonography

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.

The memorial symptom assessment scale short form (MSAS-SF)

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.

The value of CT-guided percutaneous needle aspiration in immunocompromised patients with suspected pulmonary infection

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.

Validation of the Edmonton Symptom Assessment Scale

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.

Primary amyloidoma of the cervical spine

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.

Symptom and quality of life survey of medical oncology patients at a veterans affairs medical center: a role for symptom assessment

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.

Drinking patterns in the American Deep South

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.

Pharmacokinetic and pharmacodynamic characterization of OROS and immediate-release amitriptyline

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.

Prediction of the deficit syndrome from initial deficit symptoms in the early course of schizophrenia

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.

Testosterone pharmacokinetics after application of an investigational transdermal system in hypogonadal men

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.

Transdermal testosterone administration in hypogonadal men: comparison of pharmacokinetics at different sites of application and at the first and fifth days of application

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.

Blunt traumatic rupture of the diaphragm: sonographic diagnosis

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.

DeMonS--a new deconvolution method for estimating drug absorbed at different time intervals and/or drug disposition model parameters using a monotonic cubic spline

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.

Comparison of the nicotine pharmacokinetics of Nicoderm (nicotine transdermal system) and half-hourly cigarette smoking

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.

In vitro and in vivo evaluation of a once-daily controlled-release pseudoephedrine product

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)

Evaluation of diurnal variation in fentanyl clearance

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.

In search of Asian war brides

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.

Effect of noise on the detection of rib fractures by residents

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.

In vivo evaluation of controlled-release products

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.

Interpretation and utilization of effect and concentration data collected in an in vivo pharmacokinetic and in vitro pharmacodynamic study

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.

Treatments of depression and the functional capacity to work

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.

cis-acting lesions targeted to the hydrophobic domain of a poliovirus membrane protein involved in RNA replication

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.

Identification of envelope V3 loop as the major determinant of CD4 neutralization sensitivity of HIV-1

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.

Comparison of plasma nicotine concentrations after application of nicoderm (nicotine transdermal system) to different skin sites

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.

System functionality and physicochemical model of fentanyl transdermal system

Fentanyl is an opioid traditionally administered by infusion or injection and more recently in a rate-controlled transdermal dosage form. This system is a four-layer laminate on a protective liner. A backing layer seals and protects the drug reservoir, the source for continuous delivery of fentanyl. A membrane controls the release rate of fentanyl from the system. An adhesive layer attaches the system to skin and releases an initial loading dose of fentanyl. The rate of fentanyl delivery through skin is determined by the system and the skin at the application site. The release rate from the system is approximated by Fick's first law of diffusion and is controlled by the rate-controlling membrane. A complete simulation model that combines both in vitro release data and the pharmacokinetic model has been developed and used to show the influence of various physiologic and system variables on serum fentanyl concentrations.

Identification of the envelope V3 loop as the primary determinant of cell tropism in HIV-1

Cells of the monocyte-macrophage lineage are targets for human immunodeficiency virus-1 (HIV-1) infection in vivo. However, many laboratory strains of HIV-1 that efficiently infect transformed T cell lines replicate poorly in macrophages. A 20-amino acid sequence from the macrophage-tropic BaL isolate of HIV-1 was sufficient to confer macrophage tropism on HTLV-IIIB, a T cell line--tropic isolate. This small sequence element is in the V3 loop, the envelope domain that is the principal neutralizing determinant of HIV-1. Thus, the V3 loop not only serves as a target of the host immune response but is also pivotal in determining HIV-1 tissue tropism.

A mutant poliovirus containing a novel proteolytic cleavage site in VP3 is altered in viral maturation

A six-amino-acid insertion containing a Q-G amino acid pair was introduced into the carboxy terminus of the capsid protein VP3 (between residues 236 and 237). Transfection of monkey cells with full-length poliovirus cDNA containing the insertion described above yields a mutant virus (Sel-1C-02) in which cleavage occurs almost entirely at the inserted Q-G amino acid pair instead of at the wild-type VP3-VP1 cleavage site. Mutant Sel-1C-02 is delayed in the kinetics of virus production at 39 degrees C and exhibits a defect in VP0 cleavage into VP2 and VP4 at 39 degrees C. Sucrose gradient analysis of HeLa cell extracts prepared from cells infected by Sel-1C-02 at 39 degrees C shows an accumulation of fast-sedimenting replication-packaging complexes and a significant amount of uncleaved VP0 present in fractions containing mature virions. Our data provide in vivo evidence for the importance of determinants other than the conserved amino acid pair (Q-G) for recognition and cleavage of the P1 precursor by proteinase 3CD and show that an alteration in the carboxy terminus of VP3 or the amino terminus of VP1 affects the process of viral maturation.

Absorption characteristics of transdermally administered fentanyl

Fentanyl was administered intravenously and transdermally to eight surgical patients to determine the systemic bioavailability and rate of absorption of the transdermally administered drug. Serum fentanyl concentrations reached a plateau approximately 14 h after placement of the transdermal fentanyl delivery system. This plateau was maintained until removal of the system at 24 h. The decline in serum fentanyl concentrations after removal of the transdermal system had a terminal half-life of 17.0 +/- 2.3 h (mean +/- SD), considerably longer than the terminal elimination half-life seen after intravenous administration of fentanyl in the same patients (6.1 +/- 2.0 h). The rate of fentanyl absorption, predicted to be 100 micrograms/h from in vitro data, appeared to be relatively constant during a period starting 4-8 h after placement of the transdermal system until removal of the system at 24 h. The rate of absorption during this period was 91.7 +/- 25.7 micrograms/h. After removal of the transdermal fentanyl delivery system, absorption continued at a declining rate. This indicates that the long terminal half-life of serum fentanyl concentrations after transdermal system removal is due to continued slow absorption of fentanyl, probably from a cutaneous depot of drug at the site of prior transdermal system placement. At the time of removal of the transdermal fentanyl system, 1.07 +/- 0.43 mg of drug remained in this depot. Systemic fentanyl bioavailability was found to be 0.92 +/- 0.33, with no evidence of significant cutaneous metabolism or degradation by the skin's bacterial flora. The transdermal administration of fentanyl produces relatively constant serum fentanyl concentrations for significant periods of time in the postsurgical patient requiring analgesic therapy.

Simultaneous quantification of cycloserine and its prodrug acetylacetonylcycloserine in plasma and urine by high-performance liquid chromatography using ultraviolet absorbance and fluorescence after post-column derivatization

D-Cycloserine is a broad-spectrum antibiotic used with other antibiotics to treat various forms of tuberculosis. Its prodrug sodium (R)-4-[(1-methyl-3-oxo-1-butenyl)amino]-3-isoxazolidinone hemihydrate, developed for better aqueous stability and solubility, is combined with another broad-spectrum antibiotic, fludalanine. An ion-pair, reversed-phase high-performance liquid chromatographic assay has been developed to simultaneously detect cycloserine and its prodrug in plasma and urine. The prodrug is detected directly by ultraviolet absorbance and cycloserine by fluorescence following post-column derivatization.