Liquid Chromatographic Method for Determination of Iodine in Milk: Collaborative Study

Nine laboratories participated in an AOAC International/ International Dairy Federation collaborative study on a liquid chromatographic (LC) method for determination of iodine in milk. Liquid milk is passed through a 25 000 MW membrane filter to remove protein and insoluble material. Iodine (in the form of iodide) in the clear filtrate is separated by reversed-phase ion-pair LC and is detected electrochemically. Participants analyzed 2 commercial pasteurized whole milks and 5 nonfat dry milk powders in blind duplicate. Each sample was tested in duplicate on 2 days. Repeatability and reproducibility standard deviations (sr and SR, respectively) and repeatability and reproducibility relative standard deviations (RSDr and RSDR, respectively) for determinations of iodine in whole milk (mean recovery, 86.7%) were as follows: sr, 22 μg/L; SR, 22 μg/L; RSDr, 8.2%; and RSDR, 8.3%. For powdered milk (mean recovery, 91 %), the values were as follows: sr, 0.14 μg/g; SR, 0.22 μg/g; RSDr, 9.0%; and RSDR, 12.7%. The method was adopted first action by AOAC International.

Computer-related anxiety: examining the impact of technology-specific affect on the performance of a computerized neuropsychological assessment measure

This study was conducted to examine the effect of impairment status and computer-specific anxiety on the performance of a computerized neuropsychological assessment measure. Computer related anxiety was measured using a standardized self-report measure tapping anxiety specific to computers and technology. Outcome on this measure was compared with error scores and response timing variables on a computerized version of the Category Test (CT) in both normal individuals and individuals with neurological, psychiatric, or substance abuse histories. Multivariate analysis results, controlling for psychomotor performance, revealed significant main effects for group status and computer-related anxiety. CT performance was significantly related to the level of computer-related anxiety, in that high anxiety resulted in higher CT error scores and longer response times, and the negative impact of computer-related anxiety on computerized neuropsychological assessment performance was stronger in individuals with impairment histories. Our results suggest that as computer-related anxiety increases, performance on computer administered neuropsychological assessment measures tends to decrease. Key words: computers, anxiety, computer-based task performance, clinical neuropsychology, Category Test

Effect of subacute ibuprofen dosing on rectal mucosal prostaglandin E2 levels in healthy subjects with a history of resected polyps

Nonsteroidal antiinflammatory drugs are among the most promising chemopreventive agents for colorectal cancer. Although the mechanism by which nonsteroidal antiinflammatory drugs exert such effects remains to be further characterized, their best known pharmacological effect is inhibition of prostaglandin synthetase, which leads to decreases in tissue prostaglandin levels. We conducted a randomized, double-blind, controlled study to examine the effect of daily ibuprofen treatment on the rectal mucosal prostaglandin E2 (PGE2) levels in healthy subjects with a history of resected polyps. Study participants (n = 27) completed a 2-week run-in period and were then randomized to take a single, daily dose of ibuprofen (300 or 600 mg) or of a placebo for 4 weeks. Rectal biopsy specimens were taken before and after the run-in period and at 2 and 4 weeks after the ibuprofen/placebo treatment. Notably large between- and within-subject variability in the rectal mucosal PGE2 content was seen. The changes in PGE2 levels after ibuprofen/placebo treatment correlated with the baseline PGE2 content. After adjustment of the baseline values, 2 weeks of 300 mg/day of ibuprofen treatment resulted in significantly more suppression of PGE2 levels than that observed after the placebo treatment (55% versus 22% suppression from baseline; P = 0.033). Although other ibuprofen treatment schedules and doses appeared to result in suppression in the PGE2 levels, the suppression was not statistically significant because of the large variability in this measurement. Because lower doses are associated with fewer adverse effects, a dose of 300 mg of ibuprofen/day should be considered for future Phase II chemoprevention studies. Stratifying study participants, based on their baseline PGE2 levels and inclusion of a larger number of study subjects, are recommended for future trials where the rectal mucosal PGE2 level is to be used as a surrogate end point biomarker.

Plasma alpha-tocopherol concentrations after supplementation with water- and fat-soluble vitamin E

The objective of this study was to examine differences in plasma alpha-tocopherol concentrations after oral administration of pharmacologic doses of vitamin E to normal healthy subjects as RRR-alpha-tocopheryl glycol 1000 succinate (TPGS; water-miscible form) and RRR-alpha-tocopheryl acetate (TA; fat-soluble form). The study was designed to evaluate the administration of three different single doses and multiple doses for 4 wk with both preparations. Administration of 400 IU (269 mg), 800 IU (537 mg), and 1200 IU (807 mg) TPGS as a single dose resulted in slight elevation of plasma alpha-tocopherol concentrations. Administration of multiple daily doses at all three amounts of TPGS for 28 consecutive days resulted in a slight elevation of plasma alpha-to-copherol concentrations. A significant increase in plasma alpha-to-copherol concentrations was observed after ingestion of a single dose or equivalent multiple doses of TA at all three doses. As reported in the literature, in cases of cholestasis and other forms of lipid malabsorption, oral administration of TPGS is the treatment of choice. It appears that for normal adults and patients with normal lipid absorption, fat-soluble forms of vitamin E are preferable for therapeutic and prophylactic uses.

Streptococcal preseptal cellulitis complicated by the toxic Streptococcus syndrome

BACKGROUND

After decades of decline in the incidence of severe infections secondary to group A streptococci, a dramatic increase in the frequency and severity of infections with these organisms has been reported since 1984, including a "toxic Streptococcus syndrome," resembling staphylococcal toxic shock syndrome. To the authors' knowledge, this entity has never been described after ocular infection.

METHODS

In a previously healthy 3-year-old boy, preseptal cellulitis developed secondary to minor trauma to the eyelid, progressing rapidly to hypotension, respiratory distress, and an erythrodermic desquamating rash. Ocular and blood cultures grew group A beta-hemolytic streptococci. Appropriate antibiotic coverage and management of systemic manifestations led to rapid improvement, although necrosis developed in the right upper anterior eyelid, requiring skin grafts.

RESULTS

More than 3 years since the incident, the patient is free of infection and has a good cosmetic result after skin grafting and revisions for scarring and adhesions.

CONCLUSIONS

Streptococcal preseptal cellulitis is not unusual, particularly after trauma. Ophthalmologists must be aware of the re-emergence of more virulent organisms with increased potential for morbidity and mortality.

Determination of Oltipraz in serum by high-performance liquid chromatography with optical absorbance and mass spectrometric detection

Three methods have been developed for the analysis of Oltipraz in serum. A method suitable for routine use employs spiking with a homologous internal standard, off-line solid-phase extraction, high-performance liquid chromatographic separation, and optical absorbance detection at 450 nm. Method detection limit is about 1 ng/ml. A second method, less susceptible to bias from co-eluting interferences, uses a stable isotope-labeled internal standard, similar extraction and separation, and detection by thermospray mass spectrometry. Method detection limit is about 0.2 ng/ml. A third method was developed which can be used without specially synthesized internal standards. It uses on-line solid-phase extraction, with quantification by comparison with external standards. Method detection limit is about 3 ng/ml. Good agreement was observed between these methods and with similar and different methods run in other laboratories. Calibration curves were linear over the entire range which was investigated, i.e., up to 500 ng/ml. Coefficients of variation were similar for all three methods, being about 5%.

Clinical pharmacology studies of oltipraz--a potential chemopreventive agent

Pharmacological studies on Oltipraz [4-methyl-5(pyrazinyl-2)-1-2-dithiole-3-thione)] were conducted with normal healthy subjects using various doses and schedules. Administration of single doses (1, 2 and 3 mg/kg) resulted in detectable drug levels in the serum (mean peak serum concentrations 16, 61 and 205 ng, respectively) and urine. The t1/2 was short (4.4, 4.1 and 5.3 hours respectively) and no steady state was achieved after multiple daily doses for 12 days. Introduction of a loading dose during the first day produced a steady state when 1.5 and 2.0 mg/kg/day were used. Daily administration of Oltipraz sustained the steady state with insignificant variations. Consumption of a high fat diet increased the serum and urine concentrations of Oltipraz (30-60%) compared to the low fat diet. Two subjects experienced flatulence during the administration of the drug. One subject developed numbness and pain in the thumbs with occurrence of small purplish-black spots resembling those observed in subacute endocarditis. These changes disappeared 10 days after discontinuation of the drug. No changes in peripheral blood counts, biochemical profile or thyroid function tests were observed after four weeks of Oltipraz. Further studies with a larger number of healthy subjects are needed for clarification of the safety and biological efficacy of small doses of Oltipraz during chronic administration.

Determination of glycyrrhetinic acid in human plasma by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method has been developed for measuring 18 beta-glycyrrhetinic acid (GRA) in human plasma in the range of 0.1-3 micrograms/ml. The acetate ester of GRA is added to the plasma as an internal standard, plasma proteins are denatured with urea to release GRA, and the GRA and the internal standard are extracted in an ion-pairing solid-phase extraction process. An isocratic, reversed-phase HPLC separation is used, followed by ultraviolet absorbance detection at 248 nm. The results from the analysis of five GRA-fortified plasma pools show a mean relative standard deviation of 7% and are accurate to within 10%. With evaporative concentration of the extract, the limit of detection for GRA in plasma is approximately 10 ng/ml.

Quantitative Determination of Mono- and Diglycerides with and without Derivatization by Capillary Supercritical Fluid Chromatography

Mono- and diglycerides, as well as commercial monoglyceride emulsifiers, were analyzed by capillary supercritical fluid chromatography (SFC). Carbon dioxide without modifier was used as the mobile phase in the chromatography. Samples were prepared by simply being dissolved in solvents or by propionyl ester derivatization. A capillary SFC methyl silicone column (SB-methyl 100, 100 μm X 10 m, 0.5 μm film thickness, Lee Scientific) was used for the separation, and a flame ionization detector was used for the detection. A calibration standard containing known concentrations of monomyristln, monopalmitin, monostearin, dimyristin, dlpalmitin, and distearin were used for the determination of the response factor (unit weight per peak area) of each analyte. The response factors were used in the quantitation of the analytes in the test samples from their respective integrated peak areas. Monomyristin was used as an internal standard for the quantitation of monoglycerides In commercial emulsifiers. The accuracy of the methods was demonstrated by comparing the percent area (%A) determined by the chromatography with the percent weight (%W) of each of the components in the standard mixture, and the precision of the methods was indicated by the relative standard deviation (RSD). The mean ratio and RSD of %A/%W were 0.98 ± 0.09 (<5%) and 1.01 ± 0.03 (<2.5%) for underlvatized and derivatized samples, respectively. Two lots of commercial monoglyceride emulsifiers were analyzed with and without derivatization, and the results were compared to those obtained by gas chromatography (GC). 7-tests comparing the method means did not indicate any significant mean differences (95% confidence level) between the GC and SFC methods. Nor did the variance ratio F-test indicate that the overall variances of the methods were significantly different. However, the error variance of the SFC-underivatized method was significantly higher than that of the GC and SFCderivatized methods. These results demonstrated the feasibility of applying the SFC technology in the analysis of monoand diglycerides with and without derivatization

Plasma tocopherol concentrations in response to supplemental vitamin E

Normal healthy volunteers were studied after various doses of dl-alpha-tocopherol were ingested on different schedules. Administration of 440, 880, or 1320 mg (400, 800, or 1200 IU) of dl-alpha-tocopherol as a single dose resulted in elevation of plasma alpha-tocopherol concentrations that peaked at 12-24 h. Chronic administration of dl-alpha-tocopherol (440, 880, or 1320 mg/d for 28 d) resulted in a steady state that occurred by days 4-5 of supplementation. Discontinuation of the treatment after day 28 was associated with a decline of plasma alpha-tocopherol, which returned to the pretreatment concentrations between 12 and 20 d. The plasma elevation of alpha-tocopherol was affected by dietary fat intake. Individuals consuming a high-fat diet showed significantly greater plasma alpha-tocopherol concentrations as compared with those fed a low-fat diet. The results of this study indicate that plasma kinetics of alpha-tocopherol are similar when supplements of 440, 880, or 1320 mg dl-alpha-tocopherol are given to normal, healthy individuals.

Alteration of retinol-binding-protein concentrations by the synthetic retinoid fenretinide in healthy human subjects

Normal subjects received fenretinide (HPR), 200 mg/d, on three schedules. Schedule 1 was treatment for 28 d. Schedule 2 consisted of 14 d of treatment, 3 d hiatus, and a second drug course of 14 d, 10,000 IU vitamin A was administered during the 3-d hiatus. Schedule 3 was 14 d of treatment followed by a rest period of 7 d and then 14 d of treatment. Increase in plasma HPR was accompanied by an even higher increase in the metabolite N-(4-methoxyphenyl)-all-trans-retinamide (MPR). The administration of HPR was associated with a significant reduction in retinol-binding protein (RBP), which returned to pretreatment values after the drug treatment was discontinued. Reduction of plasma retinol was also observed. Use of interrupted schedules with resting periods of 3 and 7 d changed HPR, MPR, and RBP concentrations in plasma. Addition of vitamin A did not affect the pattern of the measured variables in the plasma.

Tolerability of the synthetic retinoid Fenretinide (HPR)

Fenretinide, N-(4-hydroxyphenyl)retinamide (HPR), is a synthetic retinoid which has been proven effective in inducing cell differentiation and in inhibiting carcinogen induced mammary tumors in rodents. Because of its efficacy and low toxicity in animals, HPR has been proposed for chemopreventive evaluation in humans. Thus, a randomized trial has been conducted to select a dose which can be administered over a lengthy period of time and with acceptable toxicity. The retinoid was administered orally to patients already operated on for breast cancer in daily doses of 100, 200 and 300 mg for 6 months and subsequently at 200 mg for another 6 months. No acute toxicity was found. Dermatological toxicity was minimal and no liver function abnormalities were observed. Nausea and headaches were infrequent and always mild. Menstrual irregularities were recorded with similar frequency in the treatment and placebo groups and appeared to be more age related than drug dependent. After 6 months of treatment one of 25 patients taking 300 mg HPR daily experienced impaired night vision, confirmed by the electroretinogram, and resolved by interruption of treatment. Because the 300 mg daily dose is possibly associated with impaired dark adaptation, the recommended dose for chemoprevention trials of HPR is 200 mg per day.

Fractures of the distal phalanges

A prospective study of 110 patients with fractures of the distal phalanx indicates that less than one in three patients with such injuries will have recovered after six months. Less than one half of distal phalangeal fractures will have united by then. Factors that carry a poor prognosis include osteolysis of fractured fragments, subungual haematomas and non-union of fractures.

Bioavailability of beta-carotene in humans

Normal healthy volunteers were studied after they ingested various beta-carotene doses. Daily administration of 15 or 45 mg beta-carotene resulted in significant increase in plasma beta-carotene levels. The extent of increase and the pattern of plasma beta-carotene levels showed substantial interindividual variation. Absorption of beta-carotene was affected by dietary fat concentration. Individuals placed on a high-fat diet showed significant increases in plasma beta-carotene as compared with those placed on a low-fat diet. Pharmacological doses of beta-carotene (45 and 90 mg) were used in intermittent schedules (5-6 d intervals) without altering the steady state of beta-carotene plasma levels. Yellowing of the skin occasionally occurred during daily dosing with 45 mg beta-carotene without evidence of toxicity. The observed individual variation in bioavailability of beta-carotene raises questions regarding clinical use of this micronutrient. It appears that determination of target plasma beta-carotene concentrations is essential for effective use of this compound in prevention or treatment.

Fractures of the Distal Phalanges

A prospective study of 110 patients with fractures of the distal phalanx indicates that less than one in three patients with such injuries will have recovered after six months. Less than one half of distal phalangeal fractures will have united by then.

Factors that carry a poor prognosis include osteolysis of fractured fragments, subungual haematomas and non-union of fractures.

Pneumococcal vaccination in children with acute lymphocytic leukemia

Sixty-three children with ALL in CCR and treated according to a standard therapy protocol were immunized with the 14-valent pneumococcal vaccine. Forty-six children were vaccinated 1, 3, or 6 months following initial induction remission; 15 were vaccinated 4-6 weeks following successful completion of 30 months of antileukemia therapy; and two were vaccinated at the time of diagnosis. Response to the vaccine was suboptimal and by the 6-month follow-up there were only two serotypes for which more than half the patients tested had greater than or equal to 300 ng antibodies N/ml.

Outcome of hepatitis in children with acute leukemia

The cases of 31 children with acute leukemia and concurrent hepatitis were evaluated for the outcome of their hepatitis. Thirteen of these children had hepatitis B and 18 children had a non-B hepatitis. Chronic hepatitis developed in more than half of the children with acute hepatitis, with the majority of cases being of the chronic, active type. A majority of these children had received at least one blood transfusion in the preceding year. No relationship was seen between the development of chronicity of the liver disease and the management of the acute hepatitis or the state of underlying disease. With the potential for a cure for acute leukemia increasing, a method of reducing the sequelae of hepatitis in children with leukemia is needed.