Automated medication distribution systems and compliance with Joint Commission standards

One health care institution's experience with an automated medication distribution (AMD) system is described, along with how the system met standards of the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). AMD units were implemented in nearly 50 patient care locations in a medical center with the goal of providing cartless distribution for over 90% of all medications. Planning for the system began in the fall of 1998; the system was fully implemented by mid-2000. In compliance with JCAHO requirements, the system provided medications in unit dose or single unit-of-use packaging, supplied drugs in a ready-to-administer form, ensured that drugs were available only near the time of administration, created a patient-specific medication profile, allowed for pharmacist review of medication orders before dispensing, provided proper storage conditions, prevented unauthorized use, allowed for access in emergencies, and met federal and state regulations. Implementation of the system improved drug distribution at the medical center and saved nursing and pharmacy time. Challenges included waits by nurses trying to access the AMD units and the extensive, ongoing education and training required for users of the system. An AMD system should be fully integrated with the health care institution's medication-use process and comply with applicable JCAHO standards.

The prevalence of glaucoma in a population-based study of Hispanic subjects: Proyecto VER

OBJECTIVE

To determine the prevalence of glaucoma in a population-based sample of Hispanic adults older than 40 years.

METHODS

Using 1990 census data for Arizona, groups of persons living in sections of the city in Nogales and Tucson were randomly selected with a probability proportional to the Hispanic population older than 40 years. We tried to recruit all eligible adults in homes with 1 self-described Hispanic adult. Detailed ocular examinations at a local clinic included visual acuity testing, applanation tonometry, gonioscopy, an optic disc evaluation, and a threshold visual field test. Open-angle glaucoma (OAG) was defined using a proposed international system for prevalence surveys, including threshold visual field defect and optic disc damage. Angle-closure glaucoma was defined as bilateral appositional angle closure, combined with optic nerve damage (judged by field and disc as for OAG).

RESULTS

Examinations were conducted in 72% (4774/6658) of eligible persons, with a 1.97% prevalence (95% confidence interval, 1.58%-2.36%) of OAG (94 persons). The age-specific OAG prevalence increased nonlinearly from 0.50% in those aged 41 to 49 years to 12.63% in those 80 years and older. Angle-closure glaucoma was detected in 5 persons (0.10%). Sex, blood pressure, and cigarette smoking were not significant OAG risk factors. Only 36 (38%) of the 94 persons with OAG were aware of their OAG before the study. Screening results with an intraocular pressure higher than 22 mm Hg (in the eye with a higher pressure) would miss 80% of the OAG cases.

CONCLUSIONS

The prevalence of OAG in Hispanic persons was intermediate between reported values for white and black persons. The prevalence increased more quickly with increasing age than in other ethnic groups. Glaucoma was the leading cause of bilateral blindness.

Pharmacokinetic studies in Tg.AC and FVB mice administered [14C] benzene either by oral gavage or intradermal injection

Chronic benzene toxicity has been demonstrated to result in either aplastic anemia or acute myelogenous leukemia, a form of granulocytic leukemia, in exposed people (Snyder and Kalf, Crit. Rev. Toxicol. 24, 177-209, 1994). Aplastic anemia has been demonstrated in animal models following benzene exposure but, heretofore, it has not been possible to replicate benzene-induced granulocytic leukemia in animals. The Tg.AC mouse appears to be the first animal model in which a granulocytic leukemia was produced by treatment with benzene (Tennant et al., The Use of Short- and Medium-Term Tests for Carcinogenic Hazard Evaluation, 1999; French and Saulnier, J. Toxicol. Environ. Health 61, 377-379, 2000). Leukemia was observed in Tg.AC mice to which benzene was administered dermally. Neither orally dosed Tg.AC mice or mice of the parental FVB strain treated by either route of exposure developed leukemia. It is well established that benzene metabolism is required to produce benzene toxicity. To determine whether metabolic differences arising from differences in route of exposure or strain of mouse directed the development of leukemia, the pharmacokinetics of benzene were compared between the two strains and between the two routes of administration. Regardless of the route of exposure or the strain of mouse, seven major metabolites plus unmetabolized benzene were detected in most samples at most time points. Few differences were observed between the two strains following either route of administration. These results suggest that the genetic modification in the Tg.AC mouse, i.e., insertion of the v-Ha-ras construct into the genome, did not disrupt any major pathways involved in determining the pharmacokinetics of benzene. Two significant differences were observed between the two routes of exposure: first, benzene was absorbed more slowly after intradermal injection than after oral gavage, and second, the intradermally dosed mice produced more conjugates of hydroquinone than did the orally dosed mice. These differences in metabolism may be involved in the previously observed differences in hematotoxicity between the two routes of exposure.

Diabetes and diabetic retinopathy in a Mexican-American population: Proyecto VER

OBJECTIVES

The prevalence rate of diabetes is probably higher in Hispanics than in Caucasians, although there is controversy about differences in the risk of diabetic retinopathy. The purpose of the study is to determine the prevalence rates of diabetes and diabetic retinopathy in a population-based study of Hispanics aged > or = 40 years.

RESEARCH DESIGN AND METHODS

Proyecto VER is a random sample of Hispanic populations aged > or = 40 years in Arizona. A total of 4,774 individuals (71.6% of the eligible sample) completed the examinations. Diabetes was defined as self-report of a physician diagnosis or HbA(1c) value of > or = 7.0%. Diabetic retinopathy was assessed on stereo fundus photographs of fields 1, 2, and 4.

RESULTS

The prevalence rate of diabetes in the Hispanic community (individuals > or = 40 years of age) was 22%. The prevalence rate of diabetic retinopathy (DR) was 48%; 32% had moderate to severe nonproliferative and proliferative retinopathy. DR increased with increasing duration of diabetes and increasing level of HbA(1c). The prevalence rate of DR-like changes in the sample of individuals without diabetic retinopathy was 15% and was not associated with hypertension, systolic blood pressure, or diastolic blood pressure.

CONCLUSIONS

The prevalence rate of diabetes in this population of Hispanics is high, almost twice that of Caucasians. The prevalence rate of DR is high but similar to reports in a Caucasian population. The prevalence rate of 9% moderate to severe retinopathy in the newly diagnosed group suggests that efforts to improve detection and treatment of diabetes in Hispanics may be warranted.

Superior efficacy of letrozole versus tamoxifen as first-line therapy for postmenopausal women with advanced breast cancer: results of a phase III study of the International Letrozole Breast Cancer Group

PURPOSE

To compare the efficacy and tolerability of tamoxifen with that of letrozole, an oral aromatase inhibitor, with tamoxifen as first-line therapy in postmenopausal women with advanced breast cancer.

PATIENTS AND METHODS

Nine hundred seven patients were randomly assigned letrozole 2.5 mg once daily (453 patients) or tamoxifen 20 mg once daily (454 patients). Patients had estrogen receptor- and/or progesterone receptor-positive tumors, or both receptors were unknown. Recurrence during adjuvant antiestrogen therapy or within the following 12 months or prior endocrine therapy for advanced disease precluded enrollment. One prior chemotherapy regimen for metastatic disease was allowed. The primary end point was time to progression (TTP). Secondary end points included overall objective response rate (ORR), its duration, rate and duration of clinical benefit, time to treatment failure (TTF), overall survival, and tolerability.

RESULTS

TTP was significantly longer for letrozole than for tamoxifen (median, 41 v 26 weeks). Treatment with letrozole reduced the risk of progression by 30% (hazards ratio, 0.70; 95% confidence interval, 0.60 to 0.82, P =.0001). TTP was significantly longer for letrozole irrespective of dominant site of disease, receptor status, or prior adjuvant antiestrogen therapy. Similarly, TTF was significantly longer for letrozole (median, 40 v 25 weeks). ORR was higher for letrozole (30% v 20%; P =.0006), as was the rate of clinical benefit (49% v 38%; P =.001). Survival data are currently immature and not reported here. Both treatments were well tolerated.

CONCLUSION

Letrozole was significantly superior to tamoxifen in TTP, TTF, ORR, and clinical benefit rate. Our results support its use as first-line endocrine therapy in postmenopausal women with advanced breast cancer.

Psychometric properties of the 25-item NEI-VFQ in a Hispanic population: Proyecto VER

PURPOSE

To assess the psychometric properties of the NEI-VFQ-25 in a population-based study of older Hispanic persons living in the United States, explore other demographic factors that affect participant response, and observe the comparability of the Spanish and English versions of the instrument.

METHODS

A sample of randomly selected block groups in Tucson and Nogales, Arizona, were selected for study. Participants were interviewed at home; a majority of the interviews were conducted in Spanish. The home interview included questions from the NEI-VFQ-25 and HHANES: Presenting acuity was done using ETDRS methodology, followed by a standardized eye examination by an ophthalmologist. The authors analyzed the internal consistency of the NEI-VFQ-25 responses using Cronbach's alpha coefficient and the construct validity by assessing the relationship between presenting acuity and scale scores, adjusting for age and gender. A second model was also explored to determine whether other demographic variables affected scale scores; differences in reporting between the Spanish and English versions was observed in this model, used in a subset of the population that minimized interviewer effect.

RESULTS

Of the 4774 participants in the study, 99.7% had completed questionnaires, not completed by proxy. The highest nonresponse rate occurred in the Driving scale, with 25% of participants not driving for reasons other than problems with vision. Internal consistency was high, with Cronbach alpha ranging between 0.65 and 0.86 for scales with multiple items. Adjusting for age and gender, those with presenting acuity worse than 20/40 scored significantly lower than those with presenting acuity 20/40 or better, for all scales. The demographic variables with the most consistent association across the NEI-VFQ-25 scales were presenting acuity, income, and gender. No significant differences in reporting were found between the Spanish and English versions of the questionnaire in the subset of the population.

CONCLUSIONS

In this study of Hispanic people age 40 years or older, the NEI-VFQ-25 was sensitive to presenting acuity and other demographic variables, such as age, gender, and income. The findings from this psychometric analysis provide evidence of the reliability and validity of some of the scales in the 25-item NEI-VFQ when used among people with a range of visual acuity level, providing other explanatory variables are also considered.

Should Medicare HMO benefits be standardized?

Legislation enacted in 1990 standardized Medigap benefits but not the benefits of health maintenance organizations (HMOs) that serve Medicare beneficiaries. An examination of marketing materials in two large counties reveals the potential for enormous confusion among beneficiaries because of differences in wording to describe the same benefit, health plans' failure to list Medicare-covered services, and the differences in the benefits themselves. To date, the Health Care Financing Administration (HCFA) has not been able to overcome this confusion through the comparative material distributed on its Web site; indeed, significant errors were found, reflecting to some extent the underlying difficulties in characterizing benefits. Ways of ameliorating the situation are discussed.

Metabolism of [14C]phenol in the isolated perfused mouse liver

A previous report from this laboratory focused on the metabolism of [14C]benzene (BZ) in the isolated, perfused, mouse liver (C. C. Hedli, et al., 1997, Toxicol. Appl. Pharmacol. 146, 60-68). Whereas administration of BZ to mice results in bone marrow depression (R. Snyder et al., 1993, Res. Commun. Chem. Pathol. Pharmacol. 20, 191-194), administration of phenol (P), the major metabolite of BZ, does not. It was, therefore, of interest to determine whether the metabolic fate of P produced during BZ metabolism differed from that of P metabolized in the absence of BZ. Mouse livers were perfused with a solution of [14C]P in both the orthograde (portal vein to central vein) and retrograde (central vein to portal vein) direction to investigate the metabolic zonation of enzymes involved in P hydroxylation and conjugation. Perfusate samples were collected, separated by HPLC, and tested for radioactivity. Unconjugated metabolites were identified by comparing their retention times with nonradiolabeled standards, which were detected by UV absorption. Conjugated metabolites were identified and collected on the basis of radiochromatogram results, hydrolyzed enzymatically, and identified by co-chromatography with unlabeled BZ metabolites. The objective was to compare and quantify the metabolites formed during the perfusion of P in the orthograde and retrograde directions and to compare the orthograde P-perfusion results with the orthograde BZ results reported previously. Regardless of the direction of P perfusion, the major compounds released from the liver were P. phenylgucuronide, phenylsulfate, hydroquinone (HQ), and HQ glucuronide. A comparison of the results of perfusing P in the orthograde versus the retrograde direction showed that more P was recovered unchanged and more HQ was formed during retrograde perfusion. The results suggest that enzymes involved in P hydroxylation are generally closer to the central vein than those involved in conjugation, and that during retrograde perfusion, P metabolism may be limited by the sub-optimal conditions of perfusion. Comparison of the orthograde perfusion studies of P and BZ revealed that a larger percentage of the radioactivity released from the liver was identified as unconjugated HQ after BZ perfusion than after P perfusion. In addition, the amount of radioactivity covalently bound to liver macromolecules was measured after each perfusion and determined to be proportional to the amount of HQ and HQG detected in the perfusate samples.

Genetic influences on electrical seizure threshold

C57BL/6J (B6) and DBA/2J (D2) mice have been characterized previously as seizure-resistant and seizure-sensitive, respectively, a distinction based primarily upon a differential response to the convulsant effects of various drugs. In the present study, electroconvulsive shock (ECS) was used to assess maximal electroshock threshold (MET) in B6, D2 and hybrid mice. Results revealed that D2 mice have a significantly lower MET compared to B6 mice. There was also a significant gender effect for B6 and F2 mice with females exhibiting a lower MET compared to males. METs for F1 and F2 intercross mice were intermediate between the two parental strains. The difference in variance between F2 and F1 generation mice indicated that about three-quarters of the total variance is due to genetic influence. Taken together, results of this study suggest that the large difference in MET between B6 and D2 mice is a highly heritable trait which may yield to genetic dissection through use of quantitative trait locus mapping.

Investigation of hepatic cytochrome P-450 enzyme induction and DNA adduct formation in male CD/1 mice following oral administration of toxaphene

Exposure of experimental animals to toxaphene induces hepatic cytochrome P-450 (CYP). Although chronic administration of toxaphene to mice was found to cause an increased incidence of liver tumors, a mechanism for its carcinogenicity has yet to be elucidated. We investigated two potential mechanisms of toxaphene-induced carcinogenicity: peroxisomal proliferation and DNA binding. Peroxisomal proliferation was evaluated by measuring the level of immunodetectable CYP 4A1, an isozyme of CYP that is specifically induced by peroxisomal proliferators, in hepatic microsomes from CD1 mice that were treated by oral gavage for seven consecutive days with corn oil vehicle or 10, 25, 50 or 100 mg kg(-1) toxaphene. In comparison to control mice, toxaphene-treated mice had increased liver weight, increased liver/body weight ratios and increased levels of total hepatic CYP and cytochrome b5. No increase in the level of immunodetectable levels of CYP 4A1 was found in hepatic microsomes from toxaphene-treated mice when compared to controls. In contrast, increases in immunodetectable CYP 4A1 were detected in hepatic microsomes from mice treated with the peroxisomal proliferator clofibrate. These findings suggest that toxaphene-induced induction of CYP may not involve CYP 4A1 and that peroxisomal proliferation may not be involved in toxicity. Significant increases in immunodetectable levels of CYP 2B were, however, detected in toxaphene-treated mice, and are consistent with earlier reports demonstrating that toxaphene, like many other pesticides, induces the phenobarbital-inducible subfamily of CYP. Analysis of DNA adduct levels in the livers of toxaphene-treated mice by DNA 32P-post-labeling showed no evidence of DNA adduct formation.

Self-discrepancy theory, standards for body evaluation, and eating disorder symptomatology among college women

Potential links between personal and sociocultural aspects of body-image concerns and sets of behavioral and emotional symptoms associated with eating disorders were explored within a self-discrepancy theory framework. It was predicted that actual:ideal body-image discrepancies from one's own standpoint would be related to symptoms reflecting feelings like dissatisfaction and actual:ought body-image discrepancies from a societal standpoint would be related to symptoms reflecting feelings like anxiety. The Bodies Questionnaire, Eating Disorder Inventory, and demographic information were completed by 196 undergraduate women volunteers. Results generally supported the predictions, although the effects were small. Perceived body-image discrepancies from sociocultural prescriptions for slimness and appearance are more closely associated with symptoms reflecting failures to achieve these standards than with symptoms reflecting efforts to attain them. In addition, the contribution of personal ideals to bulimic symptomatology and body dissatisfaction includes concerns about body attributes not associated with weight. Possible clinical applications are discussed.

Scientific update on benzene

The mechanism of benzene toxicity has been extremely difficult to fully characterize. Much progress has been made in assessing the relative potency of benzene metabolites but specific pathways to leukemia remain to be determined. Metabolite and mechanistic studies will have to focus on aplastic anemia and MDS and separate endpoints. This may serve to clarify the array of metabolite effects and consequent disparate effects. Biomarker research can contribute to the understanding of the toxicity process. The significance of understanding benzene toxicity will also lead to better clinical treatment of aplastic anemia and therapy-related MDS and AML, detection of populations particularly susceptible to benzene toxicity, screening of populations with suspected or unknown exposures, and determination of meaningful values for occupational and individual health risk while effectively monitoring ongoing exposures for early signs of toxicity.

Benzene metabolism in the isolated perfused mouse liver

The hematotoxicity of benzene (BZ) requires its hepatic metabolism, the release of metabolites into the circulation, and the access of metabolites to the bone marrow. Although a range of potentially toxic metabolites produced by the liver was identified using subcellular systems and isolated hepatocytes, these models do not allow identification of the metabolites released from the liver with respect to time and flow through the liver. We developed an isolated perfused mouse liver model to evaluate metabolites released following a single-pass of radiolabeled BZ and after recirculation of single-pass metabolites back through the liver. Reversing the path of flow through the liver changes the orientation of hepatic oxidizing and conjugating enzymes with respect to perfusate flow. Comparison of metabolite production following normal (orthograde, portal vein to hepatic vein) perfusion with reversed (retrograde) perfusion permitted an evaluation of the impact of zonal distributions of these enzymes on BZ metabolism. The major metabolites detected by HPLC, irrespective of the direction of perfusion, were free phenol (P), phenylsulfate (PS), and phenylglucuronide (PG), plus lesser amounts of hydroquinone (HQ) and hydroquinone glucuronide (HQG). Recirculation of the products of single pass orthograde perfusion through the liver yielded P conjugates as well as low levels of free and conjugated HQ. No free P was detected after recirculation. Although no qualitative differences between orthograde and retrograde perfusion were observed, the percentage of free P and P conjugates (PS + PG) found as free P was twice as great following orthograde perfusion as compared to retrograde perfusion. These results suggest that regional differences in the zonation of enzymes involved in oxidation and conjugation may play a critical role in hepatic BZ metabolism.

Validation of cold chain procedures suitable for distribution of vaccines by public health programs in the USA

To enhance quality assurance of vaccine distribution by public health programs in the US, various methods for packing vaccines were validated. Validation involved both tests in an environmental chamber and actual shipping of packages by commercial overnight delivery service. Dry ice was used with vaccines needing to be kept at temperatures lower than -14 degrees C, and water-based cold packs with other vaccines. The latter could be used in two ways. When frozen, and placed over two or three faces of well-insulated boxes, assortments of vaccines were kept cold but not frozen for 2 days or more. However, packages with -15 degrees C cold packs may reach < 0 degree C. When cold packs at refrigerator temperature cover four to six faces of well insulated boxes, vaccine freezing in winter conditions or warming in temperate conditions was slowed considerably. These approaches, which require materials costing less than approximately 1% of the cost of the vaccines they protect, provide examples of packaging suitable for overnight delivery of vaccines in the US in different seasons.