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PubMed2003

Gemcitabine and cisplatin as induction chemotherapy for patients with unresectable Stage IIIA-bulky N2 and Stage IIIB nonsmall cell lung carcinoma: an Italian Lung Cancer Project Observational Study.

BACKGROUND: The objective of this trial was to evaluate the activity and safety of one of the newer platinum-based doublets as a neoadjuvant regimen in patients with unresectable Stage IIIA-bulky N2 and Stage IIIB nonsmall cell lung carcinoma (NSCLC). METHODS: From June 1996 to April 2000, 129 consecutive patients with locally advanced NSCLC were treated with gemcitabine, 1000 mg/m(2) on Days 1 and 8 and cisplatin, 70 mg/m(2) on Day 2 (GC) of a 21-day treatment cycle, for 4 cycles, as part of a combined-modality approach. RESULTS: After induction chemotherapy, 80 patients (62%; 95% confidence interval, 53.6-70.4%) achieved a partial response, 43 patients (33%) had stable disease, and 6 patients (5%) had disease progression during chemotherapy. Forty patients (31%), were considered resectable and underwent thoracotomy. Complete resectability was obtained in 38 patients (29%), with 2% of patients achieving a pathologic complete response. After surgery, 9 patients with Mountain Classification Stage IIIA NSCLC and 9 patients with Stage IIIB NSCLC received definitive adjuvant radiotherapy. Forty-six of 52 patients with Stage IIIB disease and 24 of 37 patients with Stage IIIA disease who were not considered suitable for surgery received definitive radiotherapy. The median time to disease progression was 11.4 months, the median survival was 19.4 months (range, 1.2-55.2 + months), and the 1-year survival rate was 74%. The lungs (33%) and the brain (21%) were the main sites of recurrence. Major toxicity was comprised of Grade 3-4 thrombocytopenia, which occurred in 34 patients (27%). CONCLUSIONS: GC administered according to a 3-week schedule was a highly active and safe regimen in patients with primary, unresectable, locally advanced NSCLC.

Adult↗

PubMed1989

Restorative proctocolectomy with ileal reservoir. Comparison of two-stage vs. three-stage procedures and analysis of factors that might affect outcome.

Restorative proctocolectomy and ileal reservoir, performed as a two-stage procedure, has the advantages of a shorter hospital stay, one less anesthetic, and a shorter time with a stoma when compared with the three-stage procedure. In a prospective, nonrandomized study of 152 consecutive patients undergoing restorative proctocolectomy (57 two-stage and 95 three-stage), the complication rates for the ileal reservoir phase and the functional results of the two- and three-stage operations were compared. The results suggest that there is no advantage to the three-stage procedure except in the following circumstances: when urgent surgery is required for the complications of ulcerative colitis, when malignancy or Crohn's disease cannot be ruled out, and when a patient with active colitis has a combination of a low hemoglobin value (male less than 13.5 g/dl, female less than 11.5 g/dl), a low serum albumin level (less than 40 g/l), and is taking oral steroids.

Adenomatous Polyposis Coli↗

PubMed1996

EAES ductal stone study. Preliminary findings of multi-center prospective randomized trial comparing two-stage vs single-stage management.

BACKGROUND: The current management of patients with ductal calculi and gallstone disease consists of endoscopic stone extraction (ESE) followed by laparoscopic cholecystectomy (LC). The advent of techniques of laparoscopic ductal stone clearance has introduced an alternative single stage laparoscopic treatment for these patients. The EAES ductal stone trial was set up to compare the relative efficacy and outcome of these two management options. METHODS: The study consists of a prospective randomized controlled clinical trial comparing two management options of patients undergoing LC and suspected of harbouring common duct stones. Patients registered into the trial are randomized to one of two arms: (i) Group A-preoperative ERC with ESE followed by LC during the same hospital admission. (ii) Group B-single stage laparoscopic management consisting of LC and laparoscopic stone extraction either by the trans-cystic duct route or by direct supraduodenal common duct exploration. RESULTS: This preliminary analysis was carried out on 207 randomized patients with comparisons being made on the intention to treat principle. The two groups (A = 106, B = 101) were comparable with respect to clinical features. ASA grade, serum biochemistry and ultrasound findings. CONCLUSIONS: These preliminary findings indicate equivalent success rates and patient morbidity between the two management options but a shorter hospital stay (cost benefit) with the single stage laparoscopic treatment. Trans-cystic duct extraction is a more benign procedure than laparoscopic supraduodenal CBD exploration and is accompanied by a significantly shorter hospital stay. The higher incidence of conversion in the single stage laparoscopic group compared to the two-stage arm is due to the preference for open common duct exploration when the laparoscopic attempt failed by the majority of participating surgeons. The results to-date suggest that in fit patients, single stage laparoscopic treatment is the better option and the role of ESE should change to selective use in those patients in whom laparoscopic ductal stone extraction has failed.

Adolescent↗

PubMed1991

Reproducibility of one-stage, two-stage and chromogenic assays of factor VIII activity: a multi-center study.

This study was aimed at assessing the reproducibility of Factor VIII assays between different laboratories using the same reagents. A total of 176 post-dose plasma samples were obtained from 8 Italian subjects with hemophilia-A treated with a single dose of Factor VIII concentrates. Three laboratories (in FRG, Italy, and Sweden) participated in the study. Frozen aliquots of each sample were dispatched to each of the laboratories, where the aliquots were assayed using the same one-stage, two-stage and chromogenic methods. The one-stage and the chromogenic methods were well reproducible between the three centers: pairwise correlation analyses yielded r-values ranging from 0.88 to 0.91 for the one-stage method and from 0.91 to 0.96 for the chromogenic method. The agreement between these two assays was less evident in samples with activity below 200 IU/L in which the one-stage gave, on average, higher Factor VIII concentrations than those provided by the chromogenic method. The two-stage method was not well reproducible, and the pairwise r-values ranged from 0.48 to 0.73. Our study emphasises the need to develop multi-center quality control programs to verify the reproducibility of Factor VIII assays.

Adolescent↗

PubMed2005

Development to the blastocyst stage of immature pig oocytes arrested before the metaphase-II stage and fertilized in vitro.

In vitro fertilization (IVF) and embryonic development of mature and meiotically arrested porcine oocytes were compared in the present study. After in vitro maturation (IVM) of cumulus-oocyte complexes for 48 h, 75.4% of them extruded a visible polar body (PB). Most of the oocytes with a first polar body (PB+ group) were at the metaphase-II (M-II) stage (91.4%). Most of the oocytes without a visible polar body (PB- group) appeared to be arrested at the germinal vesicle (GV) (41.6%) and metaphase-I (M-I) (34.0%) stages. After IVF of oocytes (day of IVF=Day 0), there was no difference between PB+ and PB- groups in rates of sperm penetration, mono-spermy, however oocyte activation rate after penetration was greater in the PB+ than in the PB- group (P<0.05). On Day 2, there was no difference between rates of embryos cleaved at the 2-4 cell stages in PB+ and PB- groups (42.1+/-48.8% and 33.6+/-2.1%, respectively). On Day 4, the rate of PB+ embryos developing beyond the 4-cell stage was greater than that of PB- embryos (P<0.05, 31.7+/-3.9% and 14.1+/-1.5%, respectively), and PB+ embryos had more cells than the PB- embryos (P<0.05, 8.3+/-0.4 and 6.0+/-0.8 cells, respectively). On Day 6, a greater proportion of PB+ embryos developed to the blastocyst stage than did PB- embryos (P<0.05, 34.6+/-2.4% and 20.7+/-2.8%, respectively). However, when the GV oocytes of the PB- group were not included in recalculations, there was no difference in blastocyst rates between M-I arrested and M-II oocytes (35.3 and 34.6%, respectively). The number of blastomere nuclei in embryos obtained from the PB+ group (52.0+/-2.5) was greater than that from the PB- group (P<0.05, 29.1+/-2.8). The proportion of degenerated parts in the blastocysts, as determined by morphological appearance, was the same in the PB+ and PB- groups. Although the quality of PB+ embryos was enhanced as compared with that of the PB- group, the proportion of inner cell mass and trophectoderm cells in PB+ and PB- blastocysts did not differ (1:1.9 and 1:2.2, respectively). Chromosome analysis revealed that PB+ blastocysts had more diploidy (P<0.05, 69.7%) than did PB- blastocysts (44.0%), whereas PB- blastocysts had more triploid cells (P<0.05, 34.0%) than did PB+ oocytes (8.4%). These results indicate that pig oocytes arrested before the M-II stage (M-I oocytes) undergo cytoplasmic maturation during maturation culture and have the same ability to develop to blastocysts after IVF as M-II oocytes, but some of them resulted in degeneration or delayed development with poor embryo quality.

Animals↗

PubMed1995

A comparison of one-stage and two-stage nonextraction alternatives in matched Class II samples.

In the treatment of Class II malocclusion, an early phase of functional appliance treatment is commonly used to simplify subsequent fixed appliance therapy and to optimize the development of the facial skeleton. Unfortunately, these expectations enjoy little support in the refereed literature. The present study therefore was undertaken to examine the benefits of a two-stage bionator/edgewise regimen in comparison to the more conventional one-stage edgewise alternative. To minimize proficiency bias, we examined the records of the one- and two-stage Class II nonextraction patients who received treatment between 1980 and 1990 by a single experienced clinician. On the basis of descriptive data from 96 sets of initial study models and lateral cephalograms, discriminant analysis was used to identify two subsamples of 36 patients who were relatively similar before treatment and thus equally susceptible to the two treatments. Of these 72 "borderline" patients, 19 subsequently underwent a change in treatment plan (to extraction or surgery), leaving 25 two-stage and 28 single-stage nonextraction patients on whom to base a comparison of treatment effects. Except for a slight posttreatment difference in age (and, hence, size), the two groups underwent skeletal changes that left them essentially indistinguishable at the end of treatment. In both groups, these skeletal changes were largely responsible for molar and overjet corrections that were nearly identical in the two groups. The rates of change, however, differed significantly. As a result, the two-stage treatments started earlier and finished later. Although the present data do not address the relative impact of the two strategies on the 10% to 15% at each tail of the distribution, the early phase of functional appliance treatment conferred no obvious, measurable benefits on the central 75%. Therefore for most nonextraction Class II patients, the choice of treatments may well constitute a practice management, rather than a biologic, decision.

Activator Appliances↗

PubMed2004

The relationship between IgA activity against 4th-stage larvae and density-dependent effects on the number of 4th-stage larvae of Teladorsagia circumcincta in naturally infected sheep.

The number of Teladorsagia circumcincta 4th-stage larvae in naturally infected lambs from a single farm varied among lambs and among different years. Within each year the distribution of 4th-stage larvae among lambs was similar to that expected from a negative binomial distribution. The ratio of 4th-stage larvae to adult T. circumcincta was low in two years with a low mean intensity of infection but high in two years with a higher mean intensity of infection. The negative binomial distribution is defined by the mean and by k, a parameter that measures dispersion; k was low when mean infection intensity was low but higher when mean infection intensity was high. As k is an inverse index of overdispersion this indicated that the distribution of 4th-stage larvae was more overdispersed at low levels of infection. In a combined analysis, the number of adult T. circumcincta and the plasma IgA activity against 4th-stage larvae were both associated with increased numbers of 4th-stage larvae. There was a statistical interaction between the number of adults and IgA activity that moderated their combined effect.

Abomasum↗

PubMed2002

Two-stage IMZ implants and ITI implants inserted in a single-stage procedure. A prospective comparative study.

The aim of this study was to evaluate the feasibility of using a two-stage implant system in a single-stage procedure and to study the impact of the microgap at crestal level and to monitor the microflora in the peri-implant area. Forty edentulous patients (Cawood & Howell class V-VI) participated in this study. After randomisation, 20 patients received two IMZ implants inserted in a single-stage procedure and 20 patients received two ITI implants. After 3 months, overdentures were fabricated, supported by a bar and clip attachment. A standardised clinical and radiographic evaluation was performed immediately after denture insertion and 6 and 12 months later. Twelve months after loading, peri-implant samples were collected with sterile paper points and analysed for the presence of putative periodontal pathogens using culture techniques. One IMZ implant was lost due to insufficient osseointegration. With regard to the clinical parameters at the 12 months evaluation, significant differences for plaque score and probing pocket depth (IMZ: mean 3.3 mm, ITI: mean 2.9 mm) were found between the two groups. The mean bone loss in the first year of functioning was 0.6 mm for both groups. Prevotella intermedia was detected more often in the ITI group (12 implants) than in the IMZ group (three implants). Porphyromonas gingivalis was found in three patients. In one of these patients an implant showed bone loss of 1.6 mm between T0 and T12. Some associations were found between clinical parameters and the target microorganisms in the ITI group. These associations were not present in the IMZ group. The short-term results indicate that two-stage implants inserted in a single-stage procedure may be as predictable as one-stage implants. The microgap at crestal level in nonsubmerged IMZ implants seems to have no adverse influence on the peri-implant microbiological colonisation and of crestal bone loss in the first year of functioning. The peri-implant sulcus can and does harbour potential periodontal pathogens without signs of peri-implantitis during the evaluation period of 1 year.

Alveolar Bone Loss↗

PubMed2002

Two-part implants inserted in a one-stage or a two-stage procedure. A prospective comparative study.

OBJECTIVE: The aim of this study was to evaluate the feasibility of using a two-part implant system in a one-stage procedure and to monitor the microflora in the peri-implant area in relation to clinical and radiographic outcome. MATERIAL AND METHODS: After randomisation, 40 edentulous patients (Cawood & Howell class V-VI) received two IMZ implants in the anterior mandible inserted by either a one-stage (n = 20) or a two-stage (n = 20) surgical procedure for overdenture treatment. A standardised clinical and radiographic evaluation was performed after denture insertion as well as 6 and 12 months thereafter. Twelve months after loading, peri-implant samples were collected and analysed for the presence of putative periodontal pathogens using culture technique. RESULTS: No striking differences were found between the two groups with regard to the clinical parameters during the evaluation period. The mean bone loss in the first year of functioning was 0.6 mm in both groups. With regard to the gingiva score, plaque score, bleeding score or bone loss between T0 and T12, no associations were found with the presence of the cultured microorganisms. An association was present between pockets >or= 4 mm and the presence of Peptostreptococcus micros in the two-stage group. CONCLUSIONS: The short-term results indicate that two-part implants inserted in a one-stage procedure may be as predictable as inserted in the common two-stage procedure. The peri-implant sulcus can and does harbour potential periodontal pathogens without significant signs of tissue breakdown.

Colony Count, Microbial↗

PubMed1996

Mutations in a subgroup of patients with mild haemophilia A and a familial discrepancy between the one-stage and two-stage factor VIII:C methods.

A subgroup of patients with haemophilia A who have a familial discrepancy between the one-stage and two-stage factor VIII:C results has previously been described. These patients show factor VIII:C levels by one-stage assay that are 2-7-fold higher than their two-stage results. We have studied 10 such families and identified six different mutations in the factor VIII gene in this group. The chemical cleavage method and DNA sequencing was used to identify mutations in factor VIII gene fragments generated by reverse transcription and PCR. All available family members were tested to confirm the presence of the mutation in affected individuals. These patients were found to have one of six single point substitutions causing a missense mutation and alteration to one codon in exons 7, 11, 14 or 18. The mutations comprise three that have not previously been described (Ala284Glu. Arg698Leu. Leu1932Phe) and three that have been previously described (Ser289Leu, Arg531His, Arg698Trp). Alterations to the amino acid composition of the A1, A2 and A3 domains of factor VIII are predicted by these molecular studies. In contrast, a control group of 23 mild haemophilia families with equivalent factor VIII:C results by one-stage and two-stage assays did not have any of the above mutations. Detailed studies in seven of these latter families identified four mutations affecting the A3, C1 and C2 domains of factor VIII. These findings suggest a genetic basis to the unusual factor VIII phenotype but do not explain the mechanism of the discrepant factor VIII activity.

Exons↗

PubMed2004

Successful staged treatment for ruptured blister-like dissecting aneurysm of the intracranial internal carotid artery: acute GDC embolization for the blister-like aneurysm followed by proximal occlusion with extracranial-intracranial bypass in the chronic stage.

The surgical treatment of ruptured blister-like dissecting aneurysm on the internal carotid artery (ICA) is still controversial. We report a case of this disease successfully managed by a staged treatment: GDC packing into the blister-like aneurysm in the acute stage followed by proximal occlusion in the chronic stage. The merit of this staged treatment is to prevent rerupture in the acute stage and to allow the proximal occlusion in the chronic stage with or without an extracranial-intracranial bypass, after assessment of tolerance of the ICA occlusion.

Acute Disease↗

PubMed1994

Familial discrepancy between the one-stage and two-stage factor VIII methods in a subgroup of patients with haemophilia A.

A higher result for plasma factor VIII:C measured by the one-stage as compared with the two-stage method has been described in some patients with haemophilia A or with von Willebrand's disorder. We used both methods to measure FVIII:C in 95 patients with haemophilia A. The results were equivalent in all 21 patients with severe haemophilia (16 families) and in 45 of the patients with mild or moderate haemophilia (18 families). However, the results were discrepant (FVIII:C by one-stage assay 2-7-fold higher than by two-stage assay) in the other 29 patients with mild or moderate haemophilia (12 other families). For each patient with discrepant FVIII:C results the classification was the same for all other affected members of his family. In some families with haemophilia A the gene defect leads to a discrepancy between the one-stage and two-stage FVIII:C results and may be more widespread than previously recognized.

Aluminum Hydroxide↗

PubMed2002

Simplified methods of implant treatment in the edentulous lower jaw. A controlled prospective study. Part I: one-stage versus two-stage surgery.

BACKGROUND: The original protocol for Brånemark System implants in the mandible was a two-stage procedure with 3 months healing time. With five or six implants and a cast framework of gold, the treatment is rather expensive, and simplified methods would be desirable. PURPOSE: The goal of this controlled serial study was to investigate the outcome of a simplified procedure with one-stage surgery, four Brånemark implants, shortened healing time, and a new titanium-acrylic fixed full prosthesis. MATERIALS AND METHODS: Eighty-two patients were treated in three different groups at two specialist centers. All patients were provided with four implants, loaded with a Procera All-in-One bridge (Nobel Biocare, Gothenburg, Sweden) after 12 weeks. In group A (n = 30), one-stage surgery was combined with two-piece implants. In group B (n = 30), the control group, two-stage surgery and two-piece implants were used. In group C (n = 22), one-stage surgery was combined with one-piece implants. Marginal bone level was rated from radiographs at implant insertion, at baseline, and after 1 year. RESULTS: The survival rate after 1 year for group A was 93.3%; group B, 97.5%; and group C, 93.2%. The differences were not statistically significant. Between fixture insertion and baseline, the average bone loss for group A was 1.2 mm; group B, 1.3 mm; and group C, 1.3 mm. No complications in the form of bridge loosening or acrylic fractures were recorded during the first year. CONCLUSIONS: The survival rates and the marginal bone changes did not differ significantly between the one-stage groups and the control group. The survival rate and the marginal bone changes were similar for one-piece and two-piece implants. Four implants were sufficient to support full fixed prostheses in the mandibles. The Procera All-in-One bridges proved to be of high quality, and no complications were experienced. key words: endosseous implants, nonsubmerged implants, one-piece implants, prospective clinical study, submerged implants

Acrylic Resins↗

PubMed1997

Passive stress-strain measurements in the stage-16 and stage-18 embryonic chick heart.

The first stress-strain measurements on embryonic cardiovascular tissue are described here, obtained from cyclic uniaxial loading of the primitive ventricle. An excised ventricular segment from Hamburger/Hamilton stage-16 or stage-18 chicks (2-1/2 and 3 days of a 21-day incubation period) was mounted longitudinally between two small wires in oxygenated Krebs-Henseleit cardioplegia solution. One wire was attached to an ultrasensitive force transducer and the other to a Huxley micromanipulator controlled by remote motor drive. A real-time video tracking system calculated three myocardial surface strains based on the positions of three surface markers while the heart was deformed in a triangular wave pattern. Force transducer output was filtered, digitally sampled, and stored with strains and time. Results were plotted as strain (longitudinal, circumferential, shear, and principal) versus time, stress versus time, and stress versus longitudinal strain. The stress-strain curves were nonlinear, even at low strain levels. The hysteresis loops were large; mean hysteresis energy as a proportion of total cycle stored strain energy was 36 percent (stage 16) and 41 percent (stage 18). We created a finite element model of the ventricle and fit the model behavior to the experimental behavior to determine parameters for a stage-18 pseudoelastic strain-energy function of exponential form. The calculated exponential parameter is significantly lower than that found in corresponding uniaxial studies of mature myocardium, possibly indicating the lower fiber content of the immature tissue. The results of this study are the first step in characterizing material properties for comparisons with later developmental stages and with impaired and altered myocardium. The long-term goal is to aid in identifying the biomechanical factors regulating growth and morphogenesis.

Animals↗

PubMed2001

Proximal hypospadias. Comparative evaluation of staged urethroplasty (modified Thiersch Duplay followed by Mathieu) and single stage on-lay island flap repair.

OBJECTIVES: Comparative analysis of functional results, complications, cosmesis, operative time and hospital stay between staged urethroplasty and single-stage on-lay island flap for proximal hypospadias. MATERIALS AND METHODS: Non-randomised single observer study of two groups of patients over a 5-year period with proximal hypospadias. Group 1 had 17 patients (mean age 17.7+/-1.6 months) who underwent a staged urethroplasty. Urethral plate was tubularised and proximal hypospadias converted to a distal hypospadias. Hooded dorsal prepuce was buttonholed and transposed ventrally to cover the neo-urethra. Subsequently a parameatal based flip flap urethroplasty completed urethral reconstruction. Group 2 had 17 patients (mean age 18.2+/-2.2 months) with a single stage inner preputial on-lay island flap based on superficial dorsal vessels. RESULTS: Mean period of follow-up has been 2.8+/-1.7 years in group 1 vs. 3.2+/-1.6 years in group 2 (p = 0.2). In both groups (34), 79% of the children who are now toilet trained and standing to void have a good calibre straight single stream of urine in a forward direction (p = 1.00). Main complication seen in both groups was urethrocutaneous fistulae: 6% (1/17) in group 1 vs. 59% (10/17) in group 2 (p = 0.0002). In both groups (34) cosmetic appearance of a natural vertical slit glanular meatus situated at the normal position on the glans was achieved (p = 1.00). Total mean duration of operative time in group 1 was 193.5+/-42.9 vs. 203+/-27.6 min in group 2 (p = 0.24). Total mean duration of hospital stay in group 1 was 3.4+/-0.6 vs. 9.2+/-2.9 days in group 2 (p = 0.0001). Total mean cost of the procedure in group 1 was 2,347.3 pounds +/- 220 vs. 3,753.5 pounds +/- 75 in group 2 (p = 0.002). CONCLUSION: Staged urethroplasty for proximal hypospadias results in a normal penis with good function, minimal complications and excellent cosmesis. Hospital stay was shorter and overall cost lower than a single stage on-lay island flap urethroplasty.

Age Factors↗

PubMed1989

Hemodynamics of the stage 12 to stage 29 chick embryo.

The heart is the first functioning organ in the embryo and provides blood flow during cardiac morphogenesis from a muscle-wrapped tube a few cells thick to the four-chambered pump. We described the hemodynamics of the chick embryo from stage 12 (50 hours of a 21-day incubation) to stage 29 (6 days), during which the embryo weight increased 120-fold. We measured ventricular, embryo and extraembryonic vascular bed wet weights, dorsal aortic blood flow with a directional pulsed-Doppler velocity meter, and ventricular and vitelline arterial blood pressures with a servo-null micropressure system. The data are reported as mean +/- SEM. With rapid development and morphogenesis, dorsal aortic blood flow increased from 0.015 +/- 0.004 to 2.40 +/- 0.20 mm3/sec parallel to the geometric increase of wet embryo weight from 2.22 +/- 0.10 to 267.5 +/- 9.7 mg. Dorsal aortic blood flow normalized for embryo and extraembryonic weight remained relatively constant (Y = 2.13 + 0.02X, r = 0.23, SEE = 0.03). Stroke volume increased from 0.01 +/- 0.003 to 0.69 +/- 0.03 mm3, and heart rate doubled from 103 +/- 2 to 208 +/- 5 beats/min. Systolic, diastolic, and mean vitelline arterial pressure increased linearly from 0.32 +/- 0.01, 0.23 +/- 0.01, and 0.28 +/- 0.01 mm Hg at stage 12 to 2.00 +/- 0.06, 1.22 +/- 0.03, and 1.51 +/- 0.04 mm Hg, respectively, at stage 29. Ventricular peak systolic and end-diastolic pressure increased from 0.95 +/- 0.04 and 0.24 +/- 0.02 at stage 12 to 3.45 +/- 0.10 and 0.82 +/- 0.03 at stage 29, respectively. The hemodynamic waveforms were similar to those found in the four-chamber heart of the mature animal. These data are integral to understanding the interrelation of function and form during cardiac development.

Animals↗

PubMed2004

Optical coherence tomography system with no high-precision scanning stage and stage controller.

Optical coherence tomography (OCT) is a novel technique for noninvasive imaging based on the use of a low-coherence interferometer. Conventionally, obtaining high-resolution images requires the use of high-precision sample and scanning stages and a stage controller for simultaneous measurement of the refractive index and the thickness of an optical sample. However, in this study a novel optical-fiber-type OCT system is developed that does not need both a high-precision scanning stage and a stage controller. Additionally, two signal demodulation processes are described. Compared with that of conventional OCT systems, the current configuration eliminates the high-precision scanning stage and stage controller and is therefore cheaper and less complex. Also, this new technique could be applied to conventional OCTs in biotissue scanning.

Equipment Design↗

PubMed1992

Comparison of a two-stage and three-stage interim-analysis procedure.

A statistical model for combining p values from multiple tests of significance is used to define rejection and acceptance regions for two-stage and three-stage sampling plans. Type I error rates, power, frequencies of early termination decisions, and expected sample sizes are compared. Both the two-stage and three-stage procedures provide appropriate protection against Type I errors. The two-stage sampling plan with its single interim analysis entails minimal loss in power and provides substantial reduction in expected sample size as compared with a conventional single end-of-study test of significance for which power is in the adequate range. The three-stage sampling plan with its two interim analyses introduces somewhat greater reduction in power, but it compensates with greater reduction in expected sample size. Either interim-analysis strategy is more efficient than a single end-of-study analysis in terms of power per unit of sample size.

Bias↗