Showing papers by "Medical University of South Carolina published in 2001"

Criteria for the classification of early systemic sclerosis.

Abstract: We propose criteria for the early diagnosis and classification of systemic sclerosis that reflect the vascular and serological advances of the last 2 decades.

The Circuitry Mediating Cocaine-Induced Reinstatement of Drug-Seeking Behavior

Abstract: The role of limbic-striato-pallidal circuitry in cocaine-induced reinstatement was evaluated. The transient inhibition of brain nuclei associated with motor systems [including the ventral tegmental area (VTA), dorsal prefrontal cortex (dPFC), core of the nucleus accumbens (NAcore), and ventral pallidum (VP)] prevented cocaine-induced reinstatement. However, only the VP proved to be necessary for food reinstatement, suggesting that the identified circuit is specific to drug-related reinstatement. Supporting the possibility that the VTA–dPFC–NAcore–VP is a series circuit mediating reinstatement, simultaneous unilateral microinjection of GABA agonists into the dPFC in one hemisphere and into the VP in the contralateral hemisphere abolished cocaine reinstatement. Although dopamine projections from the VTA innervate all three forebrain nuclei, the blockade of dopamine receptors only in the dPFC antagonized cocaine-induced reinstatement. Furthermore, DA administration into the dPFC was sufficient to elicit a reinstatement in drug-related responding. These data demonstrate that dopamine release in the dPFC initiates a dPFC–NAcore–VP series circuit that mediates cocaine-induced drug-seeking behavior.

American Cancer Society Guidelines for the Early Detection of Cancer: Update of Early Detection Guidelines for Prostate, Colorectal, and Endometrial Cancers: ALSO: Update 2001—Testing for Early Lung Cancer Detection

Abstract: Updates to the American Cancer Society (ACS) guidelines regarding screening for the early detection of prostate, colorectal, and endometrial cancers, based on the recommendations of recent ACS workshops, are presented. Additionally, the authors review the "cancer-related check-up," clinical encounters that provide case-finding and health counseling opportunities. Finally, the ACS is issuing an updated narrative related to testing for early lung cancer detection for clinicians and individuals at high risk of lung cancer in light of emerging data on new imaging technologies. Although it is likely that current screening protocols will be supplanted in the future by newer, more effective technologies, the establishment of an organized and systematic approach to early cancer detection would lead to greater utilization of existing technology and greater progress in cancer control.

Effectiveness, Transportability, and Dissemination of Interventions: What Matters When?

Abstract: The authors identify and define key aspects of the progression from research on the efficacy of a new intervention to its dissemination. They highlight the role of transportability questions that arise in that progression and illustrate key conceptual and design features that differentiate efficacy, effectiveness, and dissemination research. An ongoing study of the transportability of multisystemic therapy is used to illustrate independent and interdependent aspects of effectiveness, transportability, and dissemination studies. Variables relevant to the progression from treatment efficacy to dissemination include features of the intervention itself as well as variables pertaining to the practitioner, client, model of service delivery, organization, and service system. The authors provide examples of how some of these variables are relevant to the transportability of different types of interventions. They also discuss sample research questions, study designs, and challenges to be anticipated in the arena of transportability research.

Identification of a gene, ABCG5, important in the regulation of dietary cholesterol absorption

Abstract: The molecular mechanisms regulating the amount of dietary cholesterol retained in the body, as well as the body's ability to exclude selectively other dietary sterols, are poorly understood. An average western diet will contain about 250-500 mg of dietary cholesterol and about 200-400 mg of non-cholesterol sterols. About 50-60% of the dietary cholesterol is absorbed and retained by the normal human body, but less than 1% of the non-cholesterol sterols are retained. Thus, there exists a subtle mechanism that allows the body to distinguish between cholesterol and non-cholesterol sterols. In sitosterolemia, a rare autosomal recessive disorder, affected individuals hyperabsorb not only cholesterol but also all other sterols, including plant and shellfish sterols from the intestine. The major plant sterol species is sitosterol; hence the name of the disorder. Consequently, patients with this disease have very high levels of plant sterols in the plasma and develop tendon and tuberous xanthomas, accelerated atherosclerosis, and premature coronary artery disease. We previously mapped the STSL locus to human chromosome 2p21 and further localized it to a region of less than 2 cM bounded by markers D2S2294 and D2S2291 (M.-H.L. et al., manuscript submitted). We now report that a new member of the ABC transporter family, ABCG5, is mutant in nine unrelated sitosterolemia patients.

Enzymes of sphingolipid metabolism: from modular to integrative signaling.

Abstract: Many enzymes of sphingolipid metabolism are regulated in response to extra- and intracellular stimuli and in turn serve as regulators of levels of bioactive lipids (such as sphingosine, ceramide, sphingosine 1-phosphate, and diacylglycerol), and as such, they serve a prototypical modular function in cell regulation. However, lipid metabolism is also closely interconnected in that a product of one enzyme serves as a substrate for another. Moreover, many cell stimuli regulate more than one of these enzymes, thus adding to the complexity of regulation of lipid metabolism. In this paper, we review the status of enzymes of sphingolipid metabolism in cell regulation and propose a role for these enzymes in integration of cell responses, a role that builds on the modular organization while also taking advantage of the complexity and interconnectedness of lipid metabolism, thus providing for a combinatorial mechanism of generating diversity in cell responses. This may be a general prototype for the involvement of ...

Immune gene discovery by expressed sequence tag analysis of hemocytes and hepatopancreas in the Pacific White Shrimp, Litopenaeus vannamei, and the Atlantic White Shrimp, L. setiferus.

Abstract: A pilot program was undertaken in immune gene discovery in two sister species of litopenaeid shrimp, the Pacific white shrimp, Litopenaeus vannamei and the Atlantic white shrimp, L. setiferus. RNA from the hemocytes and hepatopancreas of single individuals from each species was recovered, 4 cDNA libraries (one from each tissue/species) were made by a PCR-based method and a total of approximately 2045 randomly selected clones were sequenced. A total of 268 expressed sequence tags (ESTs) were found that corresponded to 44 immune function genes. The most common immune-function ESTs (172) were antimicrobial peptides, which were restricted to the hemocyte libraries. Lectins were the largest group of immune-function ESTs found in the hepatopancreas. Analysis of these libraries indicates that EST approaches are effective for immune gene discovery in shrimp and that the diversity of these PCR-generated libraries would support full-scale EST collection.

Heart failure with a normal ejection fraction: Is measurement of diastolic function necessary to make the diagnosis of diastolic heart failure?

Abstract: Background—The diagnosis of diastolic heart failure is generally made in patients who have the signs and symptoms of heart failure and a normal left ventricular (LV) ejection fraction. Whether the diagnosis also requires an objective measurement of parameters that reflect the diastolic properties of the ventricle has not been established. Methods and Results—We hypothesized that the vast majority of patients with heart failure and a normal ejection fraction exhibit abnormal LV diastolic function. We tested this hypothesis by prospectively identifying 63 patients with a history of heart failure and an echocardiogram suggesting LV hypertrophy and a normal ejection fraction; we then assessed LV diastolic function during cardiac catheterization. All 63 patients had standard hemodynamic measurements; 47 underwent detailed micromanometer and echocardiographic-Doppler studies. The LV end-diastolic pressure was .16 mm Hg in 58 of the 63 patients; thus, 92% had elevated end-diastolic pressure (average, 2468 mm Hg). The time constant of LV relaxation (average, 51615 ms) was abnormal in 79% of the patients. The E/A ratio was abnormal in 48% of the patients. The E-wave deceleration time (average, 3496140 ms) was abnormal in 64% of the patients. One or more of the indexes of diastolic function were abnormal in every patient. Conclusions—Objective measurement of LV diastolic function serves to confirm rather than establish the diagnosis of diastolic heart failure. The diagnosis of diastolic heart failure can be made without the measurement of parameters that reflect LV diastolic function. (Circulation. 2001;104:779-782.)

Prevalence and Assessment of Attention-Deficit/Hyperactivity Disorder in Primary Care Settings

Abstract: Research literature relating to the prevalence of attention-deficit/hyperactivity disorder (ADHD) and co-occurring conditions in children from primary care settings and the general population is reviewed as the basis of the American Academy of Pediatrics clinical practice guideline for the assessment and diagnosis of ADHD. Epidemiologic studies revealed prevalence rates generally ranging from 4% to 12% in the general population of 6 to 12 year olds. Similar or slightly lower rates of ADHD were revealed in pediatric primary care settings. Other behavioral, emotional, and learning problems significantly co-occurred with ADHD. Also reviewed were rating scales and medical tests that could be employed in evaluating ADHD. The utility of using both parent- and teacher-completed rating scales that specifically assess symptoms of ADHD in the diagnostic process was supported. Recommendations were made regarding the assessment of children with suspected ADHD in the pediatric primary care setting.

ECT remission rates in psychotic versus nonpsychotic depressed patients: a report from CORE.

Abstract: Objective To compare the relative efficacy of electroconvulsive therapy (ECT) in psychotic and nonpsychotic patients with unipolar major depression. Methods The outcome of an acute ECT course in 253 patients with nonpsychotic (n = 176) and psychotic (n = 77) unipolar major depression was assessed in the first phase of an ongoing National Institute of Mental Health-supported four-hospital collaborative study of continuation treatments after successful ECT courses. ECT was administered with bilateral electrode placement at 50% above the titrated seizure threshold. The remission criteria were rigorous: a score ≤10 on the 24-item Hamilton Rating Scale for Depression (HRSD) after 2 consecutive treatments, and a decrease of at least 60% from baseline. Results The overall remission rate was 87% for study completers. Among these, patients with psychotic depression had a remission rate of 95% and those with nonpsychotic depression, 83%. Improvement in symptomatology, measured by the HRSD, was more robust and appeared sooner in the psychotic patients compared with the nonpsychotic patients. Conclusion Bilateral ECT is effective in relieving severe major depression. Remission rates are higher and occur earlier in psychotic depressed patients than in nonpsychotic depressed patients. These data support the argument that psychotic depression is a distinguishable nosological entity that warrants separate treatment algorithms.

Residue frequencies and pairing preferences at protein–protein interfaces

Abstract: We used a nonredundant set of 621 protein-protein interfaces of known high-resolution structure to derive residue composition and residue-residue contact preferences. The residue composition at the interfaces, in entire proteins and in whole genomes correlates well, indicating the statistical strength of the data set. Differences between amino acid distributions were observed for interfaces with buried surface area of less than 1,000 A(2) versus interfaces with area of more than 5,000 A(2). Hydrophobic residues were abundant in large interfaces while polar residues were more abundant in small interfaces. The largest residue-residue preferences at the interface were recorded for interactions between pairs of large hydrophobic residues, such as Trp and Leu, and the smallest preferences for pairs of small residues, such as Gly and Ala. On average, contacts between pairs of hydrophobic and polar residues were unfavorable, and the charged residues tended to pair subject to charge complementarity, in agreement with previous reports. A bootstrap procedure, lacking from previous studies, was used for error estimation. It showed that the statistical errors in the set of pairing preferences are generally small; the average standard error is approximately 0.2, i.e., about 8% of the average value of the pairwise index (2.9). However, for a few pairs (e.g., Ser-Ser and Glu-Asp) the standard error is larger in magnitude than the pairing index, which makes it impossible to tell whether contact formation is favorable or unfavorable. The results are interpreted using physicochemical factors and their implications for the energetics of complex formation and for protein docking are discussed. Proteins 2001;43:89-102.

Activation of Prefrontal Cortex and Anterior Thalamus in Alcoholic Subjects on Exposure to Alcohol-Specific Cues

Abstract: Background: Functional imaging studies have recently demonstrated that specific brain regions become active in cocaine addicts when they are exposed to cocaine stimuli. To test whether there are regional brain activity differences during alcohol cue exposure between alcoholic subjects and social drinkers, we designed a functional magnetic resonance imaging (fMRI) protocol involving alcohol-specific cues. Methods: Ten non‐treatment-seeking adult alcoholic subjects (2 women) (mean [SD] age, 29.9 [9.9] years) as well as 10 healthy social drinking controls of similar age (2 women) (mean [SD] age, 29.4 [8.9] years) were recruited, screened, and scanned. In the 1.5-T magnetic resonance imaging scanner, subjects were serially rated for alcohol craving before and after a sip of alcohol, and after a 9-minute randomized presentation of pictures of alcoholic beverages, control nonalcoholic beverages, and 2 different visual control tasks. During picture presentation, changes in regional brain activity were measured with the blood oxygen level‐dependent technique. Results: Alcoholic subjects, compared with the social drinking subjects, reported higher overall craving ratings for alcohol. After a sip of alcohol, while viewing alcohol cues compared with viewing other beverage cues, only the alcoholic subjects had increased activity in the left dorsolateral prefrontal cortex and the anterior thalamus. The social drinkers exhibited specific activation only while viewing the control beverage pictures. Conclusions: When exposed to alcohol cues, alcoholic subjects have increased brain activity in the prefrontal cortex and anterior thalamus—brain regions associated with emotion regulation, attention, and appetitive behavior.

Continuity of care and trust in one's physician: evidence from primary care in the United States and the United Kingdom.

Abstract: Background and objectives Patients' trust in their physician to act in their best interest contributes to the effectiveness of medical care and may be related to the structure of the health care system. This study explored the relationship between continuity of care and trust in one's physician, particularly in terms of differences between the United States and the United Kingdom (UK). Methods We conducted a cross-sectional survey of adult patients (n = 418 in the United States and n = 650 in the UK) who presented in outpatient primary care settings in the United States (Charleston, SC, and Lexington, Ky) and in the UK (Leicester and Exeter). Results A high percentage of both groups of patients reported having a usual place of care and doctor. A total of 69.8% of UK patients and 8.0% of US patients have had their regular physician for > or = 6 years. US patients (92.4%) are more likely than UK patients (70.8%) to value continuity with a doctor. Both groups had high levels of trust in their regular doctor. Trust was related to one continuity measure (length of time for the relationship) but not to another (usual provider continuity index more than 1 year). In a multivariate model, country of residence had no independent relationship with trust, but continuity of care was significantly related. Conclusions Higher continuity is associated with a higher level of trust between a patient and a physician. Efforts to improve the relationship between patients and physicians may improve the quality and outcomes of care.

Left Ventricular Remodeling in Transgenic Mice With Cardiac Restricted Overexpression of Tumor Necrosis Factor

Abstract: Background The mechanisms responsible for tumor necrosis factor (TNF)–induced LV structural remodeling in the adult heart are not known. Methods and Results We generated a line of transgenic mice (MHCsTNF) with cardiac restricted overexpression of TNF that develop progressive LV dilation/remodeling from 4 to 12 weeks of age. During the early phases of LV structural remodeling, there was a significant increase in total matrix metalloproteinase (MMP) activity that corresponded to a decrease in total myocardial fibrillar collagen content. As the MHCsTNF mice aged, there was a significant decrease in total MMP zymographic activity that was accompanied by an increase in total fibrillar collagen content. The changes in total MMP activity and myocardial fibrillar collagen content were related to a time- dependent increase in myocardial tissue inhibitor of metalloproteinases (TIMP)-1 levels, resulting in a significant time-dependent decrease in the MMP activity/TIMP level ratio in the MHCsTNF mice. To determine a...

Lack of Clinical Significance of Early Ischemic Changes on Computed Tomography in Acute Stroke

Abstract: ContextThe prevalence and clinical significance of early ischemic changes (EICs) on baseline computed tomography (CT) scan of the head obtained within 3 hours of ischemic stroke are not established.ObjectiveTo determine the frequency and significance of EIC on baseline head CT scans in the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA (recombinant tissue plasminogen activator) Stroke Trial.Design and SettingThe original study, a randomized controlled trial, took place from January 1991 through October 1994 at 43 sites, during which CT images were obtained within 3 hours of symptom onset and prior to the initiation of rt-PA or placebo. For the current analysis, detailed reevaluation was undertaken after October 1994 of all baseline head CT scans with clinical data available pretreatment (blinded to treatment arm).PatientsOf 624 patients enrolled in the trial, baseline CT scans were retrieved and reviewed for 616 (99%).Main Outcome MeasuresFrequency of EICs on baseline CT scans; association of EIC with other baseline variables; effect of EICs on deterioration at 24 hours (≥4 points increase from the baseline National Institutes of Health Stroke Scale [NIHSS] score); clinical outcome (measured by 4 clinical scales) at 3 months, CT lesion volume at 3 months, death at 90 days; and symptomatic intracranial hemorrhage (ICH) within 36 hours of treatment.ResultsThe prevalence of EIC on baseline CT in the combined rt-PA and placebo groups was 31% (n = 194). The EIC was significantly associated with baseline NIHSS score (ρ = 0.23; P<.001) and time from stroke onset to baseline CT scan (ρ = 0.11; P = .007). After adjusting for baseline variables, there was no EIC × treatment interaction detected for any clinical outcome, including deterioration at 24 hours, 4 clinical scales, lesion volume, and death at 90 days (P≥.25), implying that EIC is unlikely to affect response to rt-PA treatment. After adjusting for NIHSS score (an independent predictor of ICH), no EIC association with symptomatic ICH at 36 hours was detected in the group treated with rt-PA (P≥.22).ConclusionsOur analysis suggests that EICs are prevalent within 3 hours of stroke onset and correlate with stroke severity. However, EICs are not independently associated with increased risk of adverse outcome after rt-PA treatment. Patients treated with rt-PA did better whether or not they had EICs, suggesting that EICs on CT scan are not critical to the decision to treat otherwise eligible patients with rt-PA within 3 hours of stroke onset.

Diagnosis and management of osteomyelitis.

Abstract: Acute osteomyelitis is the clinical term for a new infection in bone. This infection occurs predominantly in children and is often seeded hematogenously. In adults, osteomyelitis is usually a subacute or chronic infection that develops secondary to an open injury to bone and surrounding soft tissue. The specific organism isolated in bacterial osteomyelitis is often associated with the age of the patient or a common clinical scenario (i.e., trauma or recent surgery). Staphylococcus aureus is implicated in most patients with acute hematogenous osteomyelitis. Staphylococcus epidermidis, S. aureus, Pseudomonas aeruginosa, Serratia marcescens and Escherichia coli are commonly isolated in patients with chronic osteomyelitis. For optimal results, antibiotic therapy must be started early, with antimicrobial agents administered parenterally for at least four to six weeks. Treatment generally involves evaluation, staging, determination of microbial etiology and susceptibilities, antimicrobial therapy and, if necessary, debridement, dead-space management and stabilization of bone.

A randomized, double-blind, placebo-controlled study of the efficacy and safety of donepezil in patients with Alzheimer's disease in the nursing home setting.

Abstract: OBJECTIVES: To evaluate the safety and efficacy of donepezil in the management of patients with Alzheimer's disease (AD) residing in nursing home facilities. DESIGN: Twenty-four-week, randomized, multicenter, parallel-group, double-blind, placebo-controlled trial. SETTING: Twenty-seven nursing homes across the United States. PARTICIPANTS: Two hundred eight nursing home patients with a diagnosis of probable or possible AD, or AD with cerebrovascular disease; mean Mini-Mental State Examination (MMSE) score 14.4; mean age 85.7. MEASUREMENTS: The primary outcome measure was the Neuropsychiatric Inventory—Nursing Home Version (NPI-NH). Secondary efficacy measures were the Clinical Dementia Rating (Nursing Home Version)—Sum of the Boxes (CDR-SB), MMSE, and the Physical Self-Maintenance Scale (PSMS). Safety was monitored by physical examinations, vital signs, clinical laboratory tests, electrocardiograms (ECGs), and treatment-emergent adverse events (AEs). RESULTS: Eighty-two percent of donepezil- and 74% of placebo-treated patients completed the trial. Eleven percent of donepezil- and 18% of placebo-treated patients withdrew because of AEs. Mean NPI-NH 12-item total scores improved relative to baseline for both groups, with no significant differences observed between the groups at any assessment. Mean change from baseline CDR-SB total score improved significantly with donepezil compared with placebo at Week 24 (P < .05). The change in CDR-SB total score was not influenced by age. Differences in mean change from baseline on the MMSE favored donepezil over placebo at Weeks 8, 16, and 20 (P < .05). No significant differences were observed between the groups on the PSMS. Overall rates of occurrence and severity of AEs were similar between the two groups (97% placebo, 96% donepezil). Gastrointestinal AEs occurred more frequently in donepezil-treated patients. In general, AEs were similar in older and younger donepezil-treated patients, with the majority of patients experiencing only AEs that were transient and mild or moderate in severity. Weight loss was reported as an AE more frequently in older patients, although a loss at last visit of ≥7% of screening weight occurred at the same rate in older and younger patients (9% of donepezil- and 6% of placebo-treated patients). No significant differences between groups in vital sign changes, bradycardia, or rates of clinically significant laboratory or ECG abnormalities were observed. CONCLUSION: Patients treated with donepezil maintained or improved in cognition and overall dementia severity in contrast to placebo-treated patients who declined during the 6-month treatment period. The safety and tolerability profile was comparable with that reported in outpatient studies of donepezil. These findings also suggest that advanced age, comorbid illnesses, and high concomitant medication usage should not be barriers to donepezil treatment. Given the apparent improvement in behavior in the placebo group, and the high use of concomitant medications in both groups, the impact of donepezil on behavior in the nursing home setting is unresolved and merits further investigation. In summary, effects on cognition, overall dementia severity, and safety and tolerability findings are consistent with previous findings in outpatients and support the use of donepezil in patients with AD who reside in nursing homes.

Clinical pharmacokinetics of quetiapine: an atypical antipsychotic.

Abstract: Quetiapine is a dibenzothiazepine derivative that has been evaluated for management of patients with the manifestations of psychotic disorders. In pharmacokinetic studies in humans, quetiapine was rapidly absorbed after oral administration, with median time to reach maximum observed plasma concentration ranging from 1 to 2 hours. The absolute bioavailability is unknown, but the relative bioavailability from orally administered tablets compared with a solution was nearly complete. Food has minimal effects on quetiapine absorption. The drug is approximately 83% bound to serum proteins. Single and multiple dose studies have demonstrated linear pharmacokinetics in the clinical dose range (up to 375mg twice daily). The drug is eliminated with a mean terminal half-life of approximately 7 hours. The primary route of elimination is through hepatic metabolism. In vitro studies show that quetiapine is predominantly metabolised by cytochrome P450 (CYP) 3A4. After administration of [14C]quetiapine, approximately 73% of the radioactivity was excreted in the urine and 21% in faeces. Quetiapine accounted for less than 1% of the excreted radioactivity. 11 metabolites formed through hepatic oxidation have been identified. Two were found to be pharmacologically active, but they circulate in plasma at 2 to 12% of the concentration of quetiapine and are unlikely to contribute substantially to the pharmacological effects of the drug. The pharmacokinetics of quetiapine do not appear to be altered by cigarette smoking. Oral clearance declines with age, and was reduced in 2 of 8 patients with hepatic dysfunction but not in patients with renal impairment. Quetiapine has no effect on the in vitro activity of CYP1A2, 2C9, 2C19, 2D6 and 3A4 at clinically relevant concentrations. The lack of effect of quetiapine on hepatic oxidation was confirmed in vivo by the lack of effect of quetiapine on antipyrine disposition. Quetiapine had no effect on serum lithium concentration. Phenytoin and thioridazine increase the clearance of quetiapine, and ketoconazole decreases clearance. No clinically significant effects of cimetidine, haloperidol, risperidone or imipramine on the pharmacokinetics of quetiapine were noted. Quetiapine dosage adjustment, therefore, may be necessary when coadministered with phenytoin, thioridazine or other potent CYP3A4 inducers or inhibitors. The relationship between the therapeutic effects and the plasma concentrations of quetiapine has been investigated in a multicentre clinical trial. There was no statistically significant association between trough plasma quetiapine concentration and clinical response as measured by traditional assessments of psychotic symptom severity. Subsequent clinical studies of the plasma concentration versus effect relationships for quetiapine may help to further define guidelines for dosage regimen design.

Two genes that map to the STSL locus cause sitosterolemia: genomic structure and spectrum of mutations involving sterolin-1 and sterolin-2, encoded by ABCG5 and ABCG8, respectively.

Abstract: Sitosterolemia is a rare autosomal recessive disorder characterized by (a) intestinal hyperabsorption of all sterols, including cholesterol and plant and shellfish sterols, and (b) impaired ability to excrete sterols into bile. Patients with this disease have expanded body pools of cholesterol and very elevated plasma plant-sterol species and frequently develop tendon and tuberous xanthomas, accelerated atherosclerosis, and premature coronary artery disease. In previous studies, we have mapped the STSL locus to human chromosome 2p21. Recently, we reported that a novel member of the ABC-transporter family, named "sterolin-1" and encoded by ABCG5, is mutated in 9 unrelated families with sitosterolemia; in the remaining 25 families, no mutations in sterolin-1 could be identified. We identified another ABC transporter, located <400 bp upstream of sterolin-1, in the opposite orientation. Mutational analyses revealed that this highly homologous protein, termed "sterolin-2" and encoded by ABCG8, is mutated in the remaining pedigrees. Thus, two highly homologous genes, located in a head-to-head configuration on chromosome 2p21, are involved as causes of sitosterolemia. These studies indicate that both sterolin-1 and sterolin-2 are indispensable for the regulation of sterol absorption and excretion. Identification of sterolin-1 and sterolin-2 as critical players in the regulation of dietary-sterol absorption and excretion identifies a new pathway of sterol transport.

The amblyopia treatment study visual acuity testing protocol.

Abstract: Objective To evaluate the reliability of a new visual acuity testing protocol for children using isolated surrounded HOTV optotypes. Methods After initial pilot testing and modification, the protocol was evaluated using the Baylor-Video Acuity Tester (BVAT) to present isolated surrounded HOTV optotypes. At 6 sites, the protocol was evaluated for testability in 178 children aged 2 to 7 years and for reliability in a subset of 88 children. Twenty-eight percent of the 178 children were classified as having amblyopia. Results Using the modified protocol, testability ranged from 24% in 2-year-olds to 96% in 5- to 7-year-olds. Test-retest reliability was high ( r = 0.82), with 93% of retest scores within 0.1 logMAR unit of the initial test score. The 95% confidence interval for an acuity score was calculated to be the score ±0.125 logMAR unit. For a change between 2 acuity scores, the 95% confidence interval was the difference ±0.18 logMAR unit. Conclusions The visual acuity protocol had a high level of testability in 3- to 7-year-olds and excellent test-retest reliability. The protocol has been incorporated into the multicenter Amblyopia Treatment Study and has wide potential application for standardizing visual acuity testing in children.