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PubMed2002

Studies on the minimal lengths required for DNA primers to be extended by the Tetrahymena telomerase: implications for primer positioning by the enzyme.

Telomerase is a specialized reverse transcriptase that contains an integral RNA subunit including a short template sequence. It extends telomeric 3' overhangs and chromosome breakpoints by catalyzing reiterative copying of this internal template into single-stranded telomeric DNA repeats. Here we report for the first time that in vitro the ciliate Tetrahymena telomerase can efficiently extend very short single-stranded DNA primers (<6 nt). These data indicate that interactions with nucleotides further upstream are not essential for elongation of longer primers. We also report that the minimal lengths required for primers to be extended by the telomerase depend on the positions along the template at which the primers are initially aligned. At a primer concentration of 2.5 micro M, primers aligned in the beginning, middle and next to the end of the template, respectively, must consist of at least 4, 5 and 6 nt to be extended by the telomerase. At a primer concentration of 50 micro M, the corresponding minimal lengths are 3, 4 and 5 nt. The systematic variation of the minimal required primer lengths supports the presence of a site within the telomerase ribonucleoprotein complex that mediates specific positioning of 3' termini of telomeric and non-telomeric DNA in the beginning of the template during telomere synthesis.

Animals↗

PubMed2003

Economic impact of extended time on peritoneal dialysis as a result of using polyglucose: the application of a Markov chain model to forecast changes in the development of the ESRD programme over time.

BACKGROUND: The use of polyglucose as a peritoneal dialysis (PD) fluid extends time on PD treatment. It is anticipated, therefore, that the share of patients treated with PD will be positively influenced. The relationship between extension of PD treatment time and an increase of the PD treatment share, however, is complex and needs further investigation. In this paper, a Markov chain model was applied to investigate the impact of extended time on PD treatment for the PD share in all dialysis patients in The Netherlands. Furthermore, the economic impact of the extended time on treatment (ETOT) was explored. METHODS: Scenarios were forecast over a 10 year period using aggregate data from the End-Stage Renal Registry in The Netherlands (Renine). Three scenarios were simulated in which the median PD technique survival was extended by 8, 10 and 12 months. Two other scenarios explored the impact of the combined effect of ETOT of 10 months together with a 10% and 20% increase of PD inflow shares. Reductions of costs to society due to ETOT were estimated using Dutch cost data on renal replacement therapies. RESULTS: PD share increases from 30.0% in the null scenario to 34.5% in the scenario with an ETOT of 10 months and an increased PD inflow share of 20%. The reduction in total costs to society of the renal replacement therapies is 0.96%. The average societal costs per discounted patient year for haemodialysis (HD) are 84 100 euros. For PD, these costs are 60 300 euros. A shift from HD to PD results in average cost savings of 28% per patient year. CONCLUSIONS: In view of high dialysis costs to society, a reduction of 0.96% can be considered to be relevant for healthcare policy makers.

Adolescent↗

PubMed2004

Detection of Campylobacter or Salmonella in turkey semen and the ability of poultry semen extenders to reduce their concentrations.

Campylobacter and Salmonella are the most commonly reported pathogens causing foodborne illness in the United States. In turkeys, the potential that semen used for artificial insemination is contaminated with these foodborne pathogens has not been investigated. Because semen on turkey farms is pooled and then used to inseminate multiple hens, contaminated semen could easily spread these bacteria throughout entire flocks via artificial insemination. The objectives of this study were to 1) determine if semen from commercial turkey farms contained these foodborne pathogens and 2) if present, evaluate the efficacy of semen extenders to reduce or eliminate Campylobacter and Salmonella from semen. Semen was collected from randomized pools of ejaculates from 10 to 30 toms per farm from 6 flocks over a 7-wk period and, on occasion, was found to contain Campylobacter, Salmonella, or both. To evaluate the efficacy of semen extenders to reduce or eliminate pathogens, pooled ejaculates were challenged with Campylobacter or Salmonella and treated with commercial poultry extenders containing various concentrations of antibiotics or an antibiotic combination previously demonstrated to remove Campylobacter from mammalian semen. Results demonstrate that commercial turkey semen may contain Campylobacter or Salmonella, and the semen extenders tested either did not reduce the bacteria or reduced but did not eliminate these bacteria from semen. We concluded that semen may be a potential vehicle for Campylobacter transfer to hens, and, if this is true, development of a method for eliminating pathogens in semen before insemination could reduce the risk of colonization.

Animals↗

PubMed2005

Effects of extended storage on egg quality factors.

Eggs were collected from a single inline processing facility weekly for 3 wk (replicates). The eggs were stored at 4 degrees C and 80% RH. Sampling began the day after collection and continued each week for 10 wk. During analysis, 24 eggs were examined for egg weight, albumen height, Haugh units (HU), shell strength, and vitelline membrane strength for each replicate. Egg weight decreased (P < 0.0001) from approximately 61 to 57 g after 10 wk of storage. Eggs from the second replicate were significantly (P < 0.0001) heavier than the other replicates by an average of 3 g. On average, albumen height decreased with extended storage (P < 0.0001) from 7.05 to 4.85 mm. Albumen height was approximately 0.2 mm higher for the eggs in replicate 2 compared with the other replicates (P < 0.01). Haugh unit values decreased during cold storage from 82.59 to 67.43 (P < 0.0001). There were no differences between replicates for HU values. No differences were detected for shell strength between replicates or during extended storage. A significant difference (P < 0.05) was found in detectable vitelline membrane strength between replicates, but this difference was less than 0.05 g. The elasticity of the vitelline membrane decreased during storage (P < 0.01) remaining low after 6 wk. Extended cold storage led to decreases in egg weight, albumen height, and HU. However, average HU values were still within the range for grade A. Shell strength was not affected by extended storage. Vitelline membrane elasticity also decreased, which could lead to yolks more easily rupturing as consumers crack the eggs. The results indicated that although the physical quality factors monitored in this study decreased during storage, egg quality was still acceptable beyond current recommended shelf life guidelines.

Animals↗

PubMed1978

A crucial factor in community program success: the extended psychosocial kinship system.

A crucial factor in community program success is the program's capacity to foster and strengthen an extended psychosocial network of neighbors, friends, and associates at work or school, as well as the extended kinship system. The chronically hospitalized patient and the young, isolated, acutely psychotic adult are both in need of an enhanced psychosocial system when entering a community program. The experience of Berkeley House, a psychiatric halfway house, is related as an example of a program that has achieved successful community tenure for its patients through the creation of an extended psychosocial kinship system. Four principal ways in which the system was sustained through the Berkeley House program are described: (1) through the ex-resident program; (2) through housing arrangements; (3) through work; and (4) through a variety of avocational and social groupings. The extended psychosocial matrix formed by overlapping groups is illustrated.

Adolescent↗

PubMed2004

Low-dose repeated caffeine administration for circadian-phase-dependent performance degradation during extended wakefulness.

OBJECTIVE: To investigate whether the effectiveness of a novel high-frequency low-dose caffeine regimen in counteracting the deterioration of performance during extended wakefulness is related to its interaction with homeostatic or circadian signals modulating performance and sleep propensity. DESIGN: Double-blind, placebo-controlled, parallel-group design in a 29-day forced desynchrony paradigm in which the period of the sleep-wake cycle was scheduled to be 42.85 hours, i.e., far removed from the circadian range. This design allowed for separate estimation of the sleep homeostatic, circadian, and caffeine contributions to performance deficits or improvements. SETTING: Private suite of a general clinical research center, in the absence of time of day information. PARTICIPANTS: Sixteen healthy normal-sleeping men (aged 18-30 years) INTERVENTIONS: Caffeine (0.3 mg per kg per hour) or placebo was administered hourly during the 28.57-hour wake episodes. RESULTS: Plasma caffeine concentrations rose in an exponential saturating manner during wakefulness. Rising caffeine levels markedly attenuated wake-dependent deterioration of a number of measures of cognitive performance, particularly at the circadian performance nadir. Moreover, caffeine enhanced the ability of subjects to remain consistently awake for extended periods, holding subjects back from completing the full transition to sleep, but at the expense of increasing subjective sleepiness. CONCLUSIONS: High-frequency low-dose caffeine administration is effective in countering the detrimental performance effects of extended wakefulness. These data are in accordance with the hypothesis that adenosine is a mediator of performance decrements associated with extended wakefulness and may lead to new strategies to use caffeine in situations in which neurobehavioral functioning is affected by sleep loss.

Adolescent↗

PubMed2004

In situ and invasive adenocarcinomas of the gallbladder extending into or arising from Rokitansky-Aschoff sinuses: a clinicopathologic study of 49 cases.

We report 49 cases of gallbladder carcinomas that extended into or originated from Rokitansky-Aschoff sinuses (RAS), all of which were resected by laparoscopic cholecystectomy. Twenty-one tumors were in situ carcinomas that extended along RAS; six in situ carcinomas arose in adenomyomatous hyperplasia and 22 were invasive adenocarcinomas with extension into RAS. Thirty-seven patients were women and 12 men. Forty patients had cholelithiasis. The age of the patients ranged from 55 to 84 years (mean 67 years). All in situ carcinomas were incidental microscopic findings in gallbladders removed for cholelithiasis and/or cholecystitis. No patient with in situ carcinoma died as a result of the tumor, including two with in situ carcinoma that originated in adenomyomatous hyperplasia and showed microinvasion. In contrast, of 15 patients with invasive well to moderately differentiated adenocarcinoma extending into RAS and invading the muscle layer or subserosal connective tissue, 8 died 2 to 4 years after surgery. Seven patients survived 1 to 8 years after cholecystectomy. Useful clues to separate RAS with in situ carcinoma from tubular neoplastic invasive glands were the following: connection of the epithelial invaginations to the surface epithelium, recognition of normal biliary epithelium admixed with neoplastic epithelium, presence of inspissated bile in long dilated spaces, and lack of invasion to the smooth muscle bundles. In situ carcinoma spreading along RAS consisted of long tubular often dilated structures extending through the intermuscular connective tissue, whereas neoplastic glands were usually small or of medium size that invaded smooth muscle bundles or intermuscular connective tissue. Perineural invasion was seen only in invasive glands located in the subserosal connective tissue. Two cases of in situ carcinoma that arose in adenomyomatous hyperplasia and three invasive adenocarcinomas that were composed predominantly of tall columnar mucin containing cells similar to gastric foveolar cells with varying degrees of atypia and cells with biliary phenotype bear some resemblance to intraductal papillary mucinous carcinoma of the pancreas or to mucinous cystic pancreatic neoplasm. Metaplastic pyloric glands often seen in the muscle layer and subserosal connective tissue maintain their lobular pattern and should not be confused with invasive glands. Our findings indicate that distinction of in situ carcinoma spreading into RAS from tubular neoplastic glands of invasive adenocarcinomas is crucial to determine prognosis in this group of patients with gallbladder carcinoma.

Adenocarcinoma↗

PubMed2000

Extended "three-in-one" block after total knee arthroplasty: continuous versus patient-controlled techniques.

UNLABELLED: This prospective, randomized, double-blinded study assessed the efficacy of patient-controlled analgesia (PCA) techniques for extended "3-in-1" block after total knee arthroplasty. A total of 45 patients were divided into three groups of 15. Over 48 h, all patients received 0.125% bupivacaine with 1 microg/mL clonidine via a femoral nerve sheath catheter in the following manner: as a continuous infusion at 10 mL/h in Group 1; as a continuous infusion at 5 mL/h plus PCA boluses (2.5 mL/30 min) in Group 2; or as PCA boluses only (10 mL/60 min) in Group 3. Pain scores, sensory block, supplemental analgesia, bupivacaine consumption, side effects, and satisfaction scores were recorded. Pain scores and supplemental analgesia were comparable in the three groups. Bupivacaine consumption was significantly less in Groups 2 and 3 than in Group 1 (P < 0.01), and in Group 3 than in Group 2 (P < 0.01). Side effects and satisfaction were comparable in the three groups. We conclude that extended "3-in-1" block provides efficient pain relief after total knee arthroplasty and that, compared with a continuous infusion, PCA techniques reduce the local anesthetic consumption without compromise in patient satisfaction or visual analog scale scores. Of the two PCA techniques tested, PCA boluses (10-mL lockout; time, 60 min) of 0.125% bupivacaine with 1 microg/mL clonidine was associated with the smallest local anesthetic consumption, and is, therefore, the recommended extended "3-in-1" block technique. IMPLICATIONS: We demonstrated that, after total knee arthroplasty, an extended "3-in-1" block consisting of patient-controlled analgesia boluses (10 mL/60 min) of 0.125% bupivacaine with 1 microg/mL clonidine provides efficient postoperative analgesia and significantly minimizes local anesthetic consumption.

Aged↗

PubMed2000

The effect of pedicle artery vasospasm on microhemodynamics in anatomically perfused and extended skin flap tissue.

The aim of this study was to evaluate quantitatively the influence of pedicle artery vasospasm on the microcirculation in skin flaps, particularly in the jeopardized extended portions. For this purpose, the hamster island skin flap model was used, which allowed for simultaneous assessment of hemodynamics in both the pedicle artery and the microvasculature of the flap by intravital microscopy. Vasospasm was induced by applying a V3 microvascular clamp for 30 seconds. Clamping resulted in a severe vasospasm, with the artery exhibiting a diameter of 7% +/- 2% (mean +/- standard error) of its original diameter (n = 10; p < 0.01), and with a reduction of total blood flow to the flap of 11% +/- 2% (p < 0.01). Diameter and blood flow recovered gradually to baseline levels after 25 and 15 minutes respectively. During recovery from severe pedicle artery vasospasm (moderate to mild vasospasm), the arterioles in the anatomically perfused flap tissue (n = 38) showed reactive vasodilation (p < 0.01), which was absent in the extended tissue (n = 49; p < 0.01 vs. anatomic). At a pedicle artery vasospasm of 50% of the original diameter, blood flow was restored to normal levels in the anatomically perfused arterioles, but remained below baseline in the extended part (partly p < 0.05 vs. baseline and anatomic). The findings suggest that the development of ischemic necrosis in extended flap portions may be promoted by prolonged, moderate vasospasm, which is well tolerated in the anatomically perfused tissue because of its high capacity for implementing compensatory local regulatory mechanisms.

Animals↗

PubMed2002

Pancreaticoduodenectomy with or without distal gastrectomy and extended retroperitoneal lymphadenectomy for periampullary adenocarcinoma, part 2: randomized controlled trial evaluating survival, morbidity, and mortality.

OBJECTIVE: To evaluate, in a prospective, randomized single-institution trial, the end points of operative morbidity, operative mortality, and survival in patients undergoing standard versus radical (extended) pancreaticoduodenectomy. SUMMARY BACKGROUND DATA: Numerous retrospective reports and a few prospective randomized trials have suggested that the performance of an extended lymphadenectomy in association with a pancreaticoduodenal resection may improve survival for patients with pancreatic and other periampullary adenocarcinomas. METHODS: Between April 1996 and June 2001, 299 patients with periampullary adenocarcinoma were enrolled in a prospective, randomized single-institution trial. After intraoperative verification (by frozen section) of margin-negative resected periampullary adenocarcinoma, patients were randomized to either a standard pancreaticoduodenectomy (removing only the peripancreatic lymph nodes en bloc with the specimen) or a radical (extended) pancreaticoduodenectomy (standard resection plus distal gastrectomy and retroperitoneal lymphadenectomy). All pathology specimens were reviewed, fully categorized, and staged. The postoperative morbidity, mortality, and survival data were analyzed. RESULTS: Of the 299 patients randomized, 5 (1.7%) were subsequently excluded because their final pathology failed to reveal periampullary adenocarcinoma, leaving 294 patients for analysis (146 standard vs. 148 radical). The two groups were statistically similar with regard to age (median 67 years) and gender (54% male). All the patients in the radical group underwent distal gastric resection, while 86% of the patients in the standard group underwent pylorus preservation ( <.0001). The mean operative time in the radical group was 6.4 hours, compared to 5.9 hours in the standard group ( =.002). There were no significant differences between the two groups with respect to intraoperative blood loss, transfusion requirements (median zero units), location of primary tumor (57% pancreatic, 22% ampullary, 17% distal bile duct, 3% duodenal), mean tumor size (2.6 cm), positive lymph node status (74%), or positive margin status on final permanent section (10%). The mean total number of lymph nodes resected was significantly higher in the radical group. Of the 148 patients in the radical group, only 15% (n = 22) had metastatic adenocarcinoma in the resected retroperitoneal lymph nodes, and none had retroperitoneal nodes as the only site of lymph node involvement. One patient in the radical group with negative pancreaticoduodenectomy specimen lymph nodes had a micrometastasis to one perigastric lymph node. There were six perioperative deaths (4%) in the standard group versus three perioperative deaths (2%) in the radical group ( = NS). The overall complication rates were 29% for the standard group versus 43% for the radical group ( =.01), with patients in the radical group having significantly higher rates of early delayed gastric emptying and pancreatic fistula and a significantly longer mean postoperative stay. With a mean patient follow-up of 24 months, there were no significant differences in 1-, 3-, or 5-year and median survival when comparing the standard and radical groups. CONCLUSIONS: Radical (extended) pancreaticoduodenectomy can be performed with similar mortality but some increased morbidity compared to standard pancreaticoduodenectomy. The data to date fail to indicate that a survival benefit is derived from the addition of a distal gastrectomy and retroperitoneal lymphadenectomy to a pylorus-preserving pancreaticoduodenectomy.

Adenocarcinoma↗

PubMed2002

Treatment of complex acetabular fractures through a modified extended iliofemoral approach.

OBJECTIVES: To assess the rate of anatomic reconstructions as well as approach-related morbidity and complications in the treatment of complex acetabular fractures through a modified extended iliofemoral approach. DESIGN: Prospective clinical study. SETTING: Level I trauma center, University Hospital. PATIENTS: Inclusion criteria were as follows: (a) associated acetabular fracture or transverse fracture with comminuted roof area stated as not sufficiently reconstructable through a single approach, and (b) age between sixteen and sixty-five years. A total of forty-nine patients with fifty complex acetabular fractures could be included out of the series of ninety-six acetabular fractures treated operatively from August 1992 to February 1996. Open reduction and internal fixation of complex acetabular fractures through the modified extended iliofemoral approach were performed. RESULTS: In 80 percent of the fifty fractures the reduction was anatomic with a remaining displacement of less than or equal to one millimeter, in eight cases there was a persistent displacement of two millimeters, and two fractures had a poor result with a three-millimeter displacement. Complications included 8 percent loss of reduction, 13 percent heterotopic ossification grade 3, and 4 percent avascular femoral head necrosis. At the two-year follow-up there were 74 percent good or excellent radiographic and clinical results. Two patients had already been reoperated with total hip replacement, and the two patients with femoral head necrosis are currently scheduled for arthroplasty. CONCLUSIONS: The modified extended iliofemoral approach proved to be appropriate to achieve anatomic reduction in complex acetabular fractures. The high rate of approach-related morbidity has to be considered carefully and may lead to a decreased incidence of extended approaches.

Acetabulum↗

PubMed1994

Health care utilization: the effect of extending insurance to adults on Medicaid or uninsured.

Current health care system reform proposals center on reducing the number of uninsured by extending private health insurance coverage. Discussion has also included enrolling Medicaid recipients in private programs. Much of the deliberation concerning extending coverage has centered on cost, but largely has not addressed the implications for health care utilization by these groups. If private insurance is extended to those currently uninsured as well as the Medicaid population, what impact will it have on utilization? Using data from the 1987 National Medical Expenditure Survey, the results of this analysis show that utilization would increase for the uninsured if private insurance benefits were extended, whereas utilization would decrease for those with Medicaid, however, the magnitude of the increase depends on the type of care.

Adult↗

PubMed1990

Transaxillary subpectoral augmentation in the ptotic breast: augmentation by disruption of the extended pectoral fascia and parenchymal sweep.

A new approach to transaxillary subpectoral breast augmentation based on an understanding of the anatomy of the extended pectoral fascia and the inframammary fold allows for the widespread application of this technique. Previous authors have stated that transaxillary augmentation is only applicable to a small subset of the general population and is contraindicated in mild degrees of ptosis or in large augmentations. The new approach, augmentation by disruption of the extended pectoral fascia technique and the parenchymal sweep maneuver, prevents high-riding implants and double folds. By disrupting the fascia, the lower portion of the implant is able to sit in a partially subglandular rather than subfascial plane. The anatomy and clinical implications of the extended pectoral fascia are discussed, as is the augmentation by disruption of the extended pectoral fascia technique. The parenchymal sweep maneuver is also described. Clinical cases are presented.

Breast↗

PubMed2002

Donor site sequelae after autologous breast reconstruction with an extended latissimus dorsi flap.

The indications for autologous reconstruction are increasing. The standard procedure is the transverse rectus abdominis muscle flap; however, this flap has contraindications and drawbacks. The latissimus dorsi muscle flap is simple and reliable. Hokin et al. demonstrated in 1983 that this flap can be extended and used for breast reconstruction without an implant. Since then, it has been widely studied in this setting and is known to provide good aesthetic results. Dorsal sequelae, conversely, were not appraised. The aim of this study was to assess objective and subjective dorsal sequelae after the harvest of an extended flap. Forty-three consecutive patients who had had breast reconstruction with an autologous latissimus dorsi flap were assessed by a surgeon and a physiotherapist for muscular strength and shoulder mobility. Patient opinion was studied through a questionnaire. Mean delay between the operation and the evaluation was 19 months. Early complications, mainly dorsal seromas, were frequent after the harvest of an extended flap (72 percent). There was no late morbidity and, especially, no flap loss or partial necrosis. As for functional results, 37 percent of the patients had complete adjustment and 70 to 87 percent demonstrated no change in shoulder strength. Sixty percent of the patients experienced no limitation in everyday life, and 90 percent said they would undergo this procedure again. The authors show that dorsal sequelae after an extended latissimus dorsi flap are minimal and that this technique compares favorably with the transverse rectus abdominis muscle flap.

Adult↗

PubMed1992

Increased islet allograft survival after extended culture by a mechanism other than depletion of donor APCs. Lack of correlation between the elimination of donor MHC class II-positive accessory cells and increased transplantability.

Neonatal rat islets derived by nonenzymic (in vitro) isolation procedures from the Fischer-344 (F-344, Rt1lv1) strain have been shown to be freely transplantable across complete MHC barriers without the use of any form of immunosuppression. However, islets obtained by in vitro isolation from some donor strains, such as the ACI, retain a degree of immunogenicity upon transplantation. This study examined the immunogenic nature of these neonatal ACI islets, and correlated this with the presence of a residual population of MHC class II-positive antigen presenting cells within the islets. In addition, further reduction of immunogenicity of isolated neonatal ACI islets by extension of the culture period was examined. Islets were obtained from neonatal ACI donors by culture-isolation and placed in secondary culture for either 2 days (10 day total culture period, standard culture) or 42 days (50 day total culture period, extended culture). Standard-culture ACI islets were rejected 33% to 100% of the time in five different recipient strains (depending on recipient strain). Compared with control grafts of fresh pancreatic fragments, rejection rates were significantly lower in two strain combinations (ACI to BUF, P = 0.044 and ACI to F-344, P = 0.028), and for all recipient strains combined (P less than 0.001). Extended-culture ACI islets survived significantly longer in all five recipient strains tested (ACI to BN, P = 0.024; ACI to BUF, P = 0.005; ACI to LEW, P = 0.004; ACI to F-344, P = 0.008 and ACI to WF, P = 0.024) and for all strains combined (P less than 0.001). No MHC class II-positive cells were detected upon examination of sectioned neonatal ACI islets using peroxidase immunocytochemistry (OX-6 antigen) in either the standard-culture or extended-culture groups. These results suggest that the increased survival of grafts of extended culture ACI islets is due to a mechanism other than the elimination of class II-positive APCs from the islets. Although possible down-regulation of MHC class II expression on residual APCs during the culture process may make identification of these cells difficult, alternative mechanisms such as the down-regulation of MHC class I antigen, resulting in the reduction of available donor target, or the existence of an accessory cell that is not constitutively MHC class II-positive, may be responsible for this increased graft survival.

Animals↗

PubMedDate not supplied

Lovastatin and extended-release niacin combination product: the first drug combination for the management of hyperlipidemia.

Advicor (lovastatin and extended-release niacin) is the first cholesterol-lowering combination product to become available for the management of hyperlipidemia. Lovastatin significantly lowers low-density lipoprotein cholesterol, whereas niacin significantly lowers triglycerides and lipoprotein (a) and markedly increases high-density lipoprotein cholesterol. These effects are ideal for managing a variety of lipid disorders, including metabolic syndrome. Lovastatin and niacin reduce coronary heart disease mortality in primary and secondary prevention patients, respectively. The extended-release niacin component uses a unique technology to minimize adverse effects (e.g., flushing and hepatotoxicity) while retaining the same lipid-altering effects as immediate-release niacin. The combination product appears to be well tolerated, with discontinuation due to adverse effects other than flushing occurring in a similar percent of patients as for lovastatin in clinical trials. Approximately 9% of patients discontinued the combination product due to flush. No confined cases of myopathy or hepatotoxicity have been reported with this product. Once-daily dosing provides ease of administration that should improve compliance and result in a greater proportion of patients meeting their low-density lipoprotein cholesterol goals. The nomenclature surrounding niacin products used to treat dyslipidemias is confusing. While only two types of niacin formulations exist (immediate-release formulations and formulations which dissolve more slowly than immediate-release formulations), government regulations allow for slowly dissolved niacin formulations to be divided into two types of niacin products; those that are available over-the-counter (OTC) and those that are available by prescription only. Over-the-counter slowly dissolved niacin preparations are not classified as OTC per se, but are considered "nutritional supplements". For this reason, they fall under the jurisdiction of the Federal Trade Commission and do not fall under the umbrella of the FDA branch that controls dyslipidemic products (Endocrine and Metabolic Division of the Center for Drug Evaluation and Research). The slowly dissolved niacin nutritional supplements have not been reviewed by the FDA for safety nor efficacy in the treatment of dyslipidemia nor are they required to meet generic drug rules (even though various brands are available). These brands are described on their labels as "sustained-release", "timed-release", and "slow-release" for example. Only two slowly absorbed niacin products have been approved by the FDA for the treatment of dyslipidemia; they are Niaspan (Kos Pharmaceuticals, Inc., Miami, FL) and Advicor (Kos Pharmaceuticals, Inc., Miami, FL). The term "extended-release" has been given to these two products to simplify the terminology and differentiate the products from immediate-release niacin. In this review, we will use "extended-release" to refer to the FDA approved slowly dissolving niacin preparation and "sustained-release" to refer to the nutritional supplements (not FDA approved).

Clinical Trials as Topic↗

PubMed2006

Psychometric characteristics and response times for content-parallel extended-matching and one-best-answer items in relation to number of options.

BACKGROUND: This study investigated the impact of item format and number of options on the psychometric characteristics (p values and biserials) and response times for multiple-choice questions (MCQs) appearing on Step 2 of the United States Medical Licensing Examination. METHOD: In all, 192 MCQ items were used in the study. Each item was presented in two formats: in a two-item extended-matching set and as an independent item. For the extended matching format, there were two versions: a base version that included all options (10 to 26) and an 8-option version. For the independent-item format, there were three versions: a base version that included all options, and 8-option and 5-option versions created by a group of physicians that selected options without information about examinee performance. All items were embedded in unscored sections of the 2005-06 Step 2 test forms. RESULTS: Versions of items with more options were harder and required more testing time; no differences in item discrimination were observed. Mean response times for items presented in the extended-matching format were lower than for those presented as independent items, primarily because of shorter response times for the second item presented in a set. CONCLUSION: Use of the extended-matching format and smaller numbers of options per item (and more items) should result in more efficient use of testing time and greater score precision per unit of testing time.

Licensure, Medical↗

PubMed2004

Extended total sacrectomy and reconstruction for sacral tumor.

STUDY DESIGN: This case report includes the results of long-term follow-up after extended total sacrectomy in a 13-year-old boy with a sarcoma originating in the sacrum with an extraskeletal extension and infiltration into the left ilium. OBJECTIVE: To report and discuss a case of sacral tumor treated by extended sacrectomy. SUMMARY OF BACKGROUND DATA: Sacral tumors are often at an advanced stage with a large volume at diagnosis. Although total or extended sacrectomy is the only radical means to treat the massive sacral tumor, unavoidable complications in total sacrectomy are serious in the treatment selection. METHODS: Initial histologic findings indicated a synovial sarcoma. Additional genetic analysis redesignated the tumor as an unclassified sarcoma. Preoperative neoadjuvant chemotherapy and radiotherapy were completed. The response to the preoperative treatment appeared as a reduction in tumor size (approximately 50%) on radiographs. After extended sacrectomy, the L5 vertebral body was fixed between the ilia, and the pelvic ring was compressed by the Zielke system. The ISOLA instrumentation system connected the lumbar spine and both ilia. All sacral nerve roots and the L5 root on the left side were cut. RESULTS: At the 5-year follow-up examination, the patient was disease-free, could walk with crutches, and could climb stairs using the handrail and one crutch. CONCLUSIONS: The patient's excellent response to preoperative antitumor treatment was considered crucial to the long-term outcome. But the decision between a radical resection with reconstruction and a less extensive procedure with combined therapy remains controversial.

Adolescent↗