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PubMed1989

[Methodological consideration on evaluation of lung cancer screening program: one-step process and two-step process].

A reasonable method to evaluate lung cancer screening program is to measure the reduction in death rate from lung cancer among those randomly allocated to screening program (one-step process). Alternative method is two-step process; step 1 is to measure what proportion of lung cancer patients, can be detected through screening and how early the screening can detected lung cancer patients, and step 2 is to delineate effectiveness of therapy following early detection. Advantages and disadvantages of the two processes were described in view of statistical power and sample size. In addition, a workplace-based screening program using chest X-ray files was mentioned as an example of step 1 of two-step process. The example also included economical consideration of the screening.

Adult↗
PubMed2006

A multiple time step algorithm compatible with a large number of distance classes and an arbitrary distance dependence of the time step size for the fast evaluation of nonbonded interactions in molecular simulations.

A new algorithm is introduced to perform the multiple time step integration of the equations of motion for a molecular system, based on the splitting of the nonbonded interactions into a series of distance classes. The interactions between particle pairs in successive classes are updated at a progressively decreasing frequency. Unlike previous multiple time-stepping schemes relying on distance classes, the present algorithm sorts interacting particle pairs by their next update times rather than by their update frequencies. For this reason, the proposed scheme is extremely flexible with respect to the number of classes that can be employed (up to hundred or more) and the distance dependence of the relative time step size (arbitrary integer function of the distance). It can also easily be adapted to classes defined based on a criterion other than the interparticle distance (e.g., interaction magnitude). Different variants of the algorithm are tested in terms of accuracy and efficiency for simulations of a pure water system (6167 molecules) under truncated-octahedral periodic boundary conditions, and compared to the twin-range method standardly used with GROMOS96 (short- and long-range cutoff distances of 0.8 and 1.4 nm, pair list and intermediate-range interactions updated every five steps). In particular, multiple time-stepping schemes with an accuracy comparable to that of the twin-range method can be designed, that permit to increase the effective (long-range) cutoff distance from 1.4 to 3.0 nm with a performance loss of only about a factor 2. This result is quite encouraging, considering the benefits of doubling the cutoff radius in the context of (bio-)molecular simulations.

Journal Article↗
PubMed1991

Early responses to double-step targets are independent of step amplitude.

We used a double-step paradigm to examine saccadic responses occurring at short intervals (50-150 ms) after the presentation of a 2-8 degrees step. Saccades occurring 60-110 ms after the second step had amplitudes independent of the step size. The amplitudes scaled to step size for intervals greater than 110 ms. These findings suggest that there is an early period of saccadic goal processing during which only information about the hemispheric location, but not the amplitude, of the target motion is available.

Humans↗
PubMed2005

Specialized 12-step programs and 12-step facilitation for the dually diagnosed.

The role of 12-step programs and 12-step-oriented treatments for dually diagnosed individuals (DDI) remains unclear. Here are presented the results of a pilot study in which 10 seriously mentally ill patients received a modified 12-step facilitation (TSF) therapy emphasizing engagement of DDI in a specialized 12-step program for DDI. Participants significantly increased their 12-step attendance and decreased their substance use during the 12 weeks of treatment. Larger and longer-term studies are needed to assess the efficacy of modified TSF for DDI relative to other treatments, and to determine what forms of TSF are most effective in this population.

Bipolar Disorder↗
PubMed1989

Comparison of saccadic eye movements in humans and macaques to single-step and double-step target movements.

Human and monkey saccade amplitude and latency, in response to 12-36 degrees target steps, differed substantially despite nearly identical experimental conditions. On single-step trials, monkeys did not undershoot targets, and latencies were insensitive to stimulus and contextual factors. Human saccades did undershoot, their latency was longer, and both undershoot and latency were affected by stimulus variables and experimental context. On double-step trials, the second target step altered primary saccade amplitude when the step occurred as little as 40 msec prior to saccade onset for both humans and monkeys. However, humans and monkeys showed somewhat different amplitude transition functions, and monkeys showed little evidence of parallel programming.

Adult↗
PubMed1983

Skin responses to step-up and step-down heating in C3H mice.

The effects of step-up (42 leads to 44 degrees C sequence) and step-down (44 leads to 42 degrees C sequence) heating were studied on the skin of C3H/He mouse feet. Skin damage in mouse feet exposed to 44 degrees C alone became proportionally more severe with increasing exposure time, while it was slight or not observed at 42 degrees C for up to 2 hr. Preheating to 42 degrees C for 60 or 120 min (step-up) had little effect on the damage from 30-60 min exposure at 44 degrees C, but increased the damage seen with 90 min at 44 degrees C. However, skin damage was markedly enhanced by exposure to step-down heating. On the other hand, thermal resistance was induced in the mouse skin by 44 degrees C fractionated treatments. The induced thermal resistance reached a maximum with a 1 day interval, and then disappeared after a 3 day interval. In another fractionation schedule of step-down heating, the enhanced skin damage which was observed when here was no interval, recovered rapidly and attained an additive response within a 1 day interval. No thermal resistance was observed.

Animals↗
PubMed2005

Designing, conducting and reporting clinical research. A step by step approach.

There are five major steps that one must navigate successfully to take a study idea and turn it into a publication that may have an impact on clinical practice. These steps include developing the study question(s), developing the study plan, implementing the study plan, reporting the results and submitting the manuscript(s) for publication. This review takes each of these steps and expands on its important components. More detail is given for steps one, two and five. Furthermore, the review is augmented with tables and checklists that may serve as tools in the planning and execution of a clinical study. Though it does not address every detail for each of the steps discussed, readers of all experience levels should find it a useful tool in the planning, execution and reporting of their next clinical study.

Biomedical Research↗
PubMed2004

Laser in situ keratomileusis to correct post-keratoplasty astigmatism; 1-step versus 2-step procedure.

PURPOSE: To investigate the correction of post-penetrating keratoplasty (PKP) astigmatism using laser in situ keratomileusis (LASIK). Visual and refractive outcomes were evaluated after LASIK was performed in 1 step (lamellar cut and ablation in 1 procedure) or 2 steps (lamellar cut then ablation in 2 successive procedures). SETTING: Department of Cornea and Refractive Surgery, Vissum-Instituto Oftalmológico de Alicante, University of Miguel Hernández, Alicante, Spain. METHODS: In this prospective observational study, 22 consecutive eyes were divided into 2 groups depending on the LASIK procedure performed to correct post-PKP astigmatism. Group 1 (1-step LASIK) included 11 eyes and Group 2 (2-step LASIK), 11 eyes. The patients were followed for 6 months. RESULTS: A statistically significant improvement was obtained in Group 2 with a mean vector analysis result of the cylinder of -4.37 diopters (D) +/- 1.79 (SD) (P = .018). In Group 1, the mean astigmatism correction was 2.38 +/- 1.71 D. The number of reoperations and residual refractive defects were significantly better in Group 2. CONCLUSION: The 2-step technique improved the accuracy of excimer laser correction of post-PKP astigmatism.

Adolescent↗
PubMed2001

Validation for MEDFICTS, a dietary assessment instrument for evaluating adherence to total and saturated fat recommendations of the National Cholesterol Education Program Step 1 and Step 2 diets.

MEDFICTS is a dietary assessment instrument designed to evaluate patient adherence to the National Cholesterol Education Program Step 1 and Step 2 diets. It provides a quick way to record food intake, portion size, and frequency of intake while focusing on foods that are the primary contributors of total fat, saturated fat, and cholesterol in the average American diet (i.e., Meats, Eggs, Dairy, Fried foods, fat In baked goods, Convenience foods, fats added at the Table and Snacks). MEDFICTS was validated in a pilot study using 16 computer-analyzed sets of 4-day food records randomly selected from 7-day food records collected in the Diet Modification Clinic at Baylor College of Medicine, Houston, Tex). MEDFICTS correctly identified the 11 patients consuming a Step 1 diet, the 2 patients consuming the Step 2 diet and the 3 patients consuming an average American diet. Pearson correlation coefficients between MEDFICTS and the 4-day records were significant for percent energy from total fat (r = 0.81, P < .0002), saturated fat (r = 0.79, P < .0003), and cholesterol (r = 0.52, P < .039). Pearson correlation coefficients from 2 follow-up validation studies (3-day diet records [n = 22] through the Mary Imogene Bassett Research Institute, Cooperstown, NY, and a second study at the Diet Modification Clinic [n = 26]) also correlated significantly with percent energy from total fat (r = 0.56, P < .006; r = 0.71, P < .0001), saturated fat (r = 0.60, P < .003; r = 0.71, P < .0001), and approached significance for cholesterol intake (r = 0.54, P < .009; r = 0.39, P < .051) respectively. MEDFICTS is a quick, efficient tool that can be used in cardiovascular health screening, clinical practice, or research for the assessment of adherence to Step 1 or 2 diets. It can be self administered, and when reviewed with a dietitian, can provide an opportunity for nutrition education.

Diet Records↗
PubMed1997

Field trial to compare pregnancy rates of bovine embryo cryopreservation methods: vitrification and one-step dilution versus slow freezing and three-step dilution.

We designed and conducted a field trial to obtain accurate pregnancy rates of Day 7 bovine embryos after vitrification in PB1 containing 6.5 M glycerol and 6% BSA (w/v) and one-step dilution in 1 M sucrose compared with controlled slow freezing in 1.5 M glycerol and three-step dilution. Embryos were collected from superovulated donor cows, and Grade 1 and 2 morulae and blastocysts were randomly assigned to each cryopreservation treatment group. Dutch farmers were solicited to participate in the field trial by an advertisement that offered cryopreserved embryos at subsidized cost. Within a period of 11 wk, one of six technicians visited 150 farms. Standard nonsurgical methods were used to transfer a total of 728 cryopreserved embryos. Recipient cows, mainly multiparous and of various breeds, the so-called "bottom-end" of the national herd, received embryos either 6, 7 or 8 d after standing estrus during natural estrous cycles. We compiled a database on 22 factors that may influence establishment of pregnancy in order to check randomization of each factor over cryopreservation treatment groups and embryo transfer technicians and to perform the statistical tests. Overall pregnancy rates were 44.5% (n = 393) for vitrified embryos and 45.1% (n = 335) for slowly frozen embryos. Pregnancy rates were not significantly different (ANOVA, P = 0.79 or Chi- square analysis, P = 0.88). The registered data confirm that all factors were randomly distributed over cryopreservation methods and technicians. Technician was not a significant source of variation in pregnancy rate (analysis of variance, P = 0.79). Although three technicians performed better with the one-step procedure and the other three performed better using the three-step method, the interaction between the technician and cryopreservation method was not significant (Tukey's test for nonadditivity, P = 0.13). Our results indicate that 1) vitrification and one-step dilution can be successfully used in the field without significant reduction in the pregnancy rate and 2) the pregnancy rate obtained using the "bottom-end" of the herd is satisfactory for practical application.

Journal Article↗
PubMed1996

Inhibition of human steroid 5alpha reductases type I and II by 6-aza-steroids: structural determinants of one-step vs two-step mechanism.

We have discovered that 17beta-[N,N-(diethyl)carbamoyl]-6-azaandrost-4-en-3-one is a time-dependent inhibitor of type II 5alpha-reductase, as is the drug finasteride. Unlike finasteride, the 6-aza-steroid is not a time-dependent inhibitor of type I 5 alpha-reductase. Finasteride inhibition of type II enzyme proceeds in a two-step mechanism. At pH 6 and 37 degrees C, an initial finasteride-reductase complex is formed with a K(i)(app) of 11.9 +/- 4.1 nM. In a second step, an irreversible complex is formed with a rate constant of inactivation of 0.09 +/- 0.01 s(-1). In contrast, the 6-aza-steroid is a reversible inhibitor. From the results of a simplified mathematical analysis, based on the rapid equilibrium approximation, the inhibitor and the enzyme form an initial complex with a K(i) of 6.8 +/- 0.2 nM. The reversible formation of a final complex, with an overall K(i) of 0.07 +/- 0.02 nM, is characterized by a first-order isomerization rate constant 0.0035 +/- 0.0001 s(-1) for the forward step and 0.00025 +/- 0.00006 s(-1) for the backward step. All rate constants for the two-step mechanism were obtained by using a general numerical integration method. The best fit values for the association and dissociation rate constants were 5.0 microM(-1) s(-1) and 0.033 +/- 0.008 s(-1), respectively, and the isomerization rate constants were 0.0035 +/- 0.007 s(-1) and 0.000076 +/- 0.000019 s(-1). These values correspond to an initial K(i) of 6.5 nM and an overall dissociation constant of 0.14 nM. The data presented here show that both finasteride and the 6-aza-steroid analogs are potent against type II 5alpha-reductase, although their mechanisms of inhibition are different.

5-alpha Reductase Inhibitors↗
PubMed1997

Nutritional intake of women and men on the NCEP Step I and Step II diets.

OBJECTIVE: Restriction of dietary fat and cholesterol are recommended for treating hyperlipidemia, but may alter vitamin or mineral intakes. We evaluated changes in nutrients of individuals taught the National Cholesterol Education Program (NCEP) Step II diet. METHODS: Subjects participated in a randomized controlled trial of the cholesterol-lowering effect of the NCEP Step II diet. Eligibility criteria included elevated fasting plasma LDL-cholesterol, no lipid-altering medications, and diet not already fat-modified. Subjects attended eight weekly dietitian-led classes. Four-day food records collected 6 months post-intervention were compared to baseline records. RESULTS: Of 409 subjects with complete data, 123 met Step I and 166 met Step II diet criteria. Intakes of micronutrients associated with fruits and vegetables (beta-carotene and vitamin A, vitamin C, folic acid, magnesium, and potassium) increased on both diets. Patterns of decreased mean intake and/or fewer subjects consuming 2/3 Recommended Dietary Allowance were seen for calcium, vitamin E, and zinc. CONCLUSIONS: NCEP Step I and II diets generally match or exceed unmodified diet for vitamin and mineral content. Premenopausal women do not appear to be at increased risk of low iron intake. Vitamin E intake decreases, although the significance is unknown in the context of lower fat intake and increased intake of other antioxidants. Diet counseling and materials should encourage sources of calcium for women, and zinc for both women and men.

Adult↗
PubMed1993

Preliminary, dermatologic first step criteria for lupus erythematosus and second step criteria for systemic lupus erythematosus.

BACKGROUND: Comparisons of cases of systemic lupus erythematosus (SLE) with cases of rheumatoid arthritis and other rheumatologic disorders affords the basis of the 1982 revised criteria of the American Rheumatism Association (ARA) for classifying SLE cases. We address three questions: Do comparisons of LE cases with non-LE cases that have suggestive skin lesions yield criteria for use in dermatology clinics for primary classification of cases with photo distributions of skin lesions? Do comparisons of SLE with cutaneous LE cases yield the same or similar criteria to the revised ARA criteria for SLE? How should subacute cutaneous LE cases be evaluated for signs of significant systemic involvement? METHODS: Discriminant analyses on 168 cases with skin lesions suggestive of LE were performed using data based on the ARA criteria for SLE and study factors for cutaneous LE suggested by the European Academy of Dermatology and Venereology. RESULTS: These yielded two sets of criteria: (1) The 11 preliminary, dermatologic first step criteria (10 plus 1 for discoid lesions and histology) serve to classify cases as LE or non-LE. (2) The 11 preliminary, dermatologic second step criteria classify LE cases as cutaneous LE or systemic LE. Interestingly, 5 of 11 of these second step criteria differ from the 11 ARA criteria for systemic LE. These second step criteria afford a useful means of distinguishing between subacute cutaneous LE cases with or without significant systemic involvement. CONCLUSIONS: The study factors included in both the first and the second step criteria fall into three groups, notably clinical criteria, laboratory criteria, and "added study factors." The latter factors distinguish between the groups compared (LE vs. non-LE and cutaneous vs. systemic LE) but not as well as the study factors included as "criteria."

Humans↗
PubMed1997

An investigation into the relation between step height and ground reaction forces in step exercise: a pilot study.

The aim of this study was to investigate the effect that changing step height had on ground reaction force. Using a randomised crossover design, 12 volunteers with no previous experience of step aerobics were recruited to perform at three different step heights: 6, 8 and 10 inches. Subjects performed a basic step at a cadence of 120 beats/min and performed three one minute trials during which ground reaction force was measured. Measurement of peak impact force, time to achieve peak impact, and total time of foot contact was made, and impulse of the force was calculated. Statistically significant differences were found to exist for peak impact force between the 6 and 8 inch and 6 and 10 inch, but not between the 8 and 10 inch conditions. No significant differences were found in any other parameters. The study supports the present advice that participants should use low step heights, and possible mechanisms of injury are discussed.

Adult↗
PubMed1998

Alpha-SNAP but not gamma-SNAP is required for ER-Golgi transport after vesicle budding and the Rab1-requiring step but before the EGTA-sensitive step.

N-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment proteins (SNAPs) have been implicated in diverse vesicular transport events; yet their exact role and site of action remain to be established. Using an established in vitro system, we show that antibodies against alpha-SNAP inhibit vesicle transport from the ER to the cis-Golgi and that recombinant alpha-SNAP enhances/stimulates the process. Cytosol immunodepleted of alpha-SNAP does not support normal transport unless supplemented with recombinant alpha-SNAP but not gamma-SNAP. In marked contrast, cytosol immunodepleted of gamma-SNAP supports ER-Golgi transport to the normal level. Neither antibodies against gamma-SNAP nor recombinant gamma-SNAP have any effect on ER-Golgi transport. These results clearly establish an essential role for alpha-SNAP but not gamma-SNAP in ER-Golgi transport. When the transport assay is performed with cytosol immunodepleted of alpha-SNAP, followed by incubation with cytosol immunodepleted of a COPII subunit, normal transport is achieved. In marked contrast, no transport is detected when the assay is first performed with cytosol depleted of the COPII subunit followed by alpha-SNAP-depleted cytosol, suggesting that alpha-SNAP is required after a step that requires COPII (the budding step). In combination with cytosol immunodepleted of Rab1, it is seen that alpha-SNAP is required after a Rab1-requiring step. It has been shown previously that EGTA blocks ER-Golgi transport at a step after vesicle docking but before fusion and we show here that alpha-SNAP acts before the step that is blocked by EGTA. Our results suggest that alpha-SNAP may be involved in the pre-docking or docking but not the fusion process.

Antibodies↗
PubMedDate not supplied

Enduring negative psychological characteristics of male and female step-children toward the step-parent.

Many divorced people remarry, and if either one or both of the remarried partners has a child or children from a former marriage, then the youth need adjust to not only the new marital structure, but to the new step-parent as well. The present research was conducted to determine: (1) enduring negative psychological characteristics of male and female step-children toward the step-parent, and (2) a comparison of the similarities and/or differences of each. Results suggested ten of the most frequently stated variables of both subject groups, similarities or significant differences between them by subject status, and their relevancy to the step-child-step-parent relationship.

Adaptation, Psychological↗
PubMed1985

Angiotensin converting enzyme inhibition in clinical practice. The second step in "stepped-care": addition or substitution?

The step-wise addition of drugs in stepped-care therapy is based in good part on the need to control different pressor mechanisms in order to lower blood pressure effectively over a long period of time. These mechanisms include the primary mechanisms assumed to be responsible for the hypertensive process and subsequently, either the mechanisms missed by the first drug or the secondary mechanisms evoked by therapy. Although stepped-care therapy has proven effective for many, its rigid application misses the importance of control of systolic blood pressure and of reversal of cardiovascular hypertrophy as additional goals of treatment. Further, the addition of a second drug might mean, in some cases, that an ineffective first drug is continued for no apparent reason. Substitution rather than addition of drugs is a reasonable option. Moreover, the advent of newer drugs with multiple mechanisms of action suggests that a step-wise addition of drugs might not be needed if the list of first step drugs is reviewed with recent advances in mind.

Antihypertensive Agents↗
PubMed1987

Cumulative ovulation rate in human menopausal/human chorionic gonadotropin-treated monkeys: "step-up" versus "step-down" dose regimens.

Cumulative ovulation rates in monkeys given human menopausal gonadotropin/human chorionic gonadotropin (hMG/hCG) on menstrual cycle days 3 to 9 in a "step-up" versus "step-down" protocol were compared with those achieved by hMG only. Using direct ovarian observation to detect sites of follicular rupture, retrograde tubal irrigation to collect eggs or embryos, and serum estradiol and progesterone levels to infer changes in ovarian status, we counted the number of ovulations at intervals of 24, 48, 72, 96, and 120 hours after hCG or comparable intervals without hCG. The data indicate (1) whereas most ovulations occurred on or before day 3 after hCG treatment, when the "step-up" dose regimen was employed additional follicles had ruptured on days 4 and 5; (2) a "step-down" protocol for hMG therapy may better synchronize follicular rupture and reduce susceptibility to delayed ovulations compared with a "step-up" dose regimen; and (3) under hMG stimulation, few follicles would rupture spontaneously (without hCG or luteinizing hormone treatment).

Animals↗