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PubMed2006

PCR and dissection as tools to monitor filarial infection of Aedes polynesiensis mosquitoes in French Polynesia.

BACKGROUND: Entomological methods may provide important tools for monitoring the transmission of filariasis in French Polynesia. In order to standardize our PCR method and refine our protocol to assess filarial infection levels in mosquitoes, we compared dissection of the vector, Aedes polynesiensis, with the poolscreening polymerase chain reaction (PS-PCR) assay. METHODS: (1) Mosquitoes were collected in human landing catches in five areas in Moorea island, French Polynesia. (2) A fraction of the captured mosquitoes was dissected for Wuchereria bancrofti larvae. (3) Laboratory-reared mosquitoes (uninfected as well as experimentally infected ones) were repeatedly tested to optimize a PS-PCR protocol (DNA extracts from 1-50 pooled mosquitoes were tested with an internal standardized system and primers specific for the Ssp1 repeat sequence. PCR products were analysed by gel electrophoresis). (4) Another fraction of the captured mosquitoes was assayed by PS-PCR according the optimized protocol. RESULTS: The prevalence of field-mosquito infection with W. bancrofti ranged from 1 to 8 % by dissection (L1-L3) and point estimates of infection prevalence, as assayed by PS-PCR, ranged from 0.4 to 3.7 %. There was a moderately strong correlation between larval infection rates as determined by dissection and PCR. DISCUSSION: Our results suggest that the PS-PCR assay is specific and highly sensitive for detecting parasite DNA. We obtained similar although not identical results with dissections of mosquitoes. PS-PCR appears to be adequate for testing large numbers of mosquitoes in the context of filariasis elimination programs. The role and advantages of using entomologic methods to monitor filariasis programs are discussed.

Journal Article↗
PubMed1994

Photodynamic therapy using m-tetra(hydroxyphenyl) chlorin. An animal model.

OBJECTIVE: To evaluate the potent photosensitizer m-tetra (hydroxyphenyl) chlorin (m-THPC) by using rabbits with cottontail rabbit papillomavirus-induced tumors and the canine larynx as model systems. DESIGN: Nonrandomized control trial. SETTING: Division of ear, nose, and throat research at a tertiary care teaching hospital. MATERIALS: Rabbits were used for relative retention ratio studies and tissue tolerance tests. Studies on the swelling of normal tissues in the larynx after photoactivation were done with canines. INTERVENTION: Animals were injected with 0.3 mg/kg of m-THPC. At varying intervals, tissues were exposed to 652 nm of light. OUTCOME MEASURES: Outcome measures consisted of four elements: (1) decay of plasma concentration over time, (2) interval to and duration of maximal ratio between drug concentration in normal tissue and tumor, (3) maximal permissible light exposure to normal tissue (skin and laryngeal mucosa) at an optimal interval, and (4) efficacy--number of tumors with partial and complete response. RESULTS: The largest papilloma to skin ratio (10:1) occurred 4 to 8 days after drug injection. The rabbit skin damage threshold was 40 to 60 J/cm2 at 6 days. The canine laryngeal edema and erythema thresholds were 50 to 70 J. A 75% cure rate of papillomas was achieved with tumors that were less than 100 mm2 in area at light doses that ranged from 25 to 75 J/cm2. CONCLUSIONS: m-THPC shows efficacy in treating papilloma virus-induced tumors. We present a protocol for rapid optimization of the factors required for tumor destruction with minimal normal tissue damage, thus permitting determination of an optimal therapeutic protocol for any photosensitizer.

Animals↗
PubMed2006

Optimizing 4D cone-beam CT acquisition protocol for external beam radiotherapy.

PURPOSE: Four-dimensional cone-beam computed tomography (4D-CBCT) imaging is sensitive to parameters such as gantry rotation speed, number of gantry rotations, X-ray pulse rate, and tube current, as well as a patient's breathing pattern. The aim of this study is to optimize the image acquisition on a patient-specific basis while minimizing the scan time and the radiation dose. METHODS AND MATERIALS: More than 60 sets of 4D-CBCT images, each with a temporal resolution of 10 phases, were acquired using multiple-gantry rotation and slow-gantry rotation techniques. The image quality was quantified with a relative root mean-square error (RE) and correlated with various acquisition settings; specifically, varying gantry rotation speed, varying both the rotation speed and the number of rotations, and varying both the rotation speed and tube current to keep the radiation exposure constant. These experiments were repeated for three different respiratory periods. RESULTS: With similar radiation dose, 4D-CBCT images acquired with low current and low rotation speed have better quality over images obtained with high current and high rotation speed. In general, a one-rotation low-speed scan is superior to a two-rotation double-speed scan, even though they provide the same number of projections. Furthermore, it is found that the image quality behaves monotonically with the relative speed as defined by the gantry rotation speed and the patient respiratory period. CONCLUSIONS: The RE curves established in this work can be used to predict the 4D-CBCT image quality before a scan. This allows the acquisition protocol to be optimized individually to balance the desired quality with the associated scanning time and patient radiation dose.

Humans↗
PubMed2000

Optimization of the fluorescence in situ hybridization (FISH) technique for high detection efficiency of very small proportions of target interphase nuclei.

Using commercially available fluorochrome-labeled probes specific for chromosomes X, Y, 13, 18, and 21, we optimized the technical protocols for fluorescence in situ hybridization (FISH) so that the highest sensitivity and specificity were achieved. Also, we compared the optical properties of different types of fluorescent labels in an effort to develop the most efficient FISH protocol, including the determination of which types of labels are the easiest to count accurately. The lymphocytes were purified from blood of normal male and female newborns, normal male and female adults, and a trisomy 21 male adult. Male and female lymphocytes were mixed in five different combinations. For each combination, the male lymphocytes either from newborns or from adults were diluted with female lymphocytes in seven different proportions. For each of these 35 different cell mixtures, 100,000 nuclei were analyzed and scored in a blind fashion. Among the different fluorochrome-labeled probes, the highest sensitivity and specificity were achieved when SpectrumAqua CEP-Y/SpectrumOrange CEP X probe mixture, SpectrumAqua CEP-18, SpectrumOrange LSI-13, and SpectrumOrange LSI-21 were hybridized. The hybridization sensitivity and specificity were higher than 99% for the identification of chromosomes X, Y, 13, and 18, and higher than 98% for the detection of trisomy 21. The proportion of false-positive signals was under 0.005% for XY detection and lower than 0.14% for autosome detection. With these high hybridization sensitivities and specificities, the optimized FISH protocol developed in our laboratory has the potential to detect very rare events, e.g., when the proportion of cells being sought is lower than 0.01%. In other words, our protocol allows the specific detection of one male cell sunken among 10,000 female cells.

Adult↗
PubMed2005

Use of follicle-stimulating hormone test to predict poor response in in vitro fertilization.

OBJECTIVE: Optimized ovarian stimulation protocols are required for the success of in vitro fertilization (IVF). The purpose of this study was to estimate whether the ovarian reserve test using exogenous follicle-stimulating hormone (FSH) could predict ovarian response in IVF. METHODS: This was a prospective observational study of 110 patients who underwent their first IVF cycle. The FSH test was administered as 150 IU of urinary FSH daily from day 3 to day 6 of the menstrual cycle preceding the IVF cycle for evaluation of the plasma estradiol level. Outcomes of IVF, including ovarian response, were analyzed. RESULTS: A negative correlation was observed between the duration of stimulation and the result of the FSH test (r = -.238, P = .014) and between the dose of FSH per retrieved mature oocyte (metaphase II oocyte) and the result of the FSH test (r = -.308, P < .001). In addition, our results showed that the result of the FSH test was significantly lower in poor responders defined by FSH of 400 IU/metaphase II oocyte or greater (207 +/- 149 compared with 293 +/- 174 pg/mL, P = .007). CONCLUSION: The FSH test can be a useful tool for determining the conditions of individualized clinical management plans and optimizing stimulation protocols in IVF.

Adult↗
PubMed2006

Postoperative rehabilitation protocols for Achilles tendon ruptures: a meta-analysis.

UNLABELLED: The optimal postoperative rehabilitation protocol after surgical repair of an Achilles tendon rupture is unknown. Although a 6-week cast immobilization is common, many early functional rehabilitation protocols have been implemented. The purpose of this study was to conduct a meta-analysis to determine if an early functional protocol for surgical repair of an acute Achilles tendon rupture improves subjective patient satisfaction without an increase in rerupture rates. Secondary outcomes of interest from an early functional protocol include infections, range of motion, strength, and minor complications. An extensive literature search for randomized or quasirandomized studies identified six trials involving 315 patients. Early functional treatment protocols, when compared with postoperative immobilization, led to more excellent rated subjective responses and no difference in rerupture rate. Our conclusions are based on six trials with small sample sizes, and larger randomized trials are required to confirm these results. LEVEL OF EVIDENCE: Therapeutic Study, Level II (Systematic review of Level II studies or Level I studies with inconsistent results).

Achilles Tendon↗
PubMedDate not supplied

Myocardial single-photon emission computed tomographic quality assurance.

In this era of cost constraints in health care and the growing demand for cost-effective clinical strategies, the nuclear cardiologist is under increasing pressure to show clear evidence that myocardial imaging studies compete favorably with other modalities. This underlines the need for ensuring consistently high image quality and accuracy using optimally chosen standardized protocol. Nuclear medicine imaging has not yet reached the level of standardization, automation, and built-in quality control of imaging modalities such as ultrasound or x-ray computerized tomography, where the press of a button guarantees a consistent high-quality image. This is due to the large number of parameters and other factors affecting image quality that each individual operator still has to choose or be aware of before commencing imaging. Of crucial importance is ensuring the correct collection of the raw data. Processing can be repeated, but errors in the raw data, if detected at all, require repeating the entire study. These errors can cause artifacts that are difficult or impossible to recognize and are the major causes of incorrect reporting. Examples are a poorly prepared radiopharmaceutical, a poor injection, scatter from "hot" areas outside myocardium, an undetected change in the photopeak window, uniformity, or center of rotation, insufficient acquisition time, camera too far from the patient, etc. The first step to guarantee consistent image quality and accuracy is the preparation and strict implementation of a quality assurance program covering all the individual stages of the procedure starting from preparation of the radiopharmaceutical and ending with processing, display, and reporting. The next step is the standardization of optimally chosen protocols with maximization of automation. Rapid built-in automated software-driven equipment quality control checks should be developed. Finally, attenuation and scatter correction, gated single-photon emission computed tomography, and the advent of digital cameras will no doubt improve quantitation and accuracy even further following clinical evaluation in close cooperation with manufacturers who have the incentive to accelerate all the above steps.

Heart↗
PubMed1999

Optimized lymphocyte protein extraction performed simultaneously with DNA and RNA isolation: application to the study of factors affecting DNA, RNA, and protein recovery from lymphocytes of the oldest individuals.

We describe an optimized procedure for protein extraction performed simultaneously with that of DNA and RNA from a single tissue sample that is, unlike the original protocol, suitable for quantitative studies. This optimized protocol is particularly well adapted to studies where gene regulation at DNA, RNA, and protein levels must be examined simultaneously, and when the amount of starting biological material is limited. We applied this procedure to the study of factors affecting both qualitatively and quantitatively the extraction of DNA, RNA, and proteins from lymphocytes of very old individuals, since we observed variability in the recovery of these molecular species with advanced age. Therefore, we investigated the combined effects of age and time delay between blood collection and lymphocyte isolation on the recovery of DNA, RNA, and proteins simultaneously extracted from Danish nonagenarians and centenarians versus younger adult samples. Our results suggest that neither RNA nor DNA nor protein contents of lymphocytes are altered with aging. However, the quantity of RNA and protein recovery is affected by a 24-h delay in blood processing. This effect is more pronounced in the oldest, particularly for RNA, and may affect data interpretation of age-dependent gene expression studies.

3T3 Cells↗
PubMed2001

Effect of gonadotrophin dose on oocyte retrieval in superovulated BALB/c mice.

Mice are commonly used animal models in reproductive and developmental research. In order to get satisfying results from such experiments, large numbers of ova must be available and this can be achieved by using various ovulation induction protocols. To obtain an optimal response from these stimulation protocols, parameters such as breeding-housing conditions of the animal strains, the best age for superovulation, and type and dose of gonadotrophins must be optimized. The aim of this study was to investigate the impact of exogenous stimulation with increasing amounts of gonadotrophins on the number and quality of oocytes/pre-embryos recovered from outbred BALB/c mice. A dose-response analysis was performed by stimulating prepubescent (21- to 25-day-old) and sexually mature (6 to 8 weeks old) female mice with hMG, which contains equal amounts of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The stimulation dose contained 5, 10, 15, 20, 25 or 30 IU of FSH/LH. The effect of increasing stimulation was assessed by monitoring the number and maturity of ova recovered from the tubes. The data were analyzed by using a one-way Anova test and student t-test. Increasing stimulation doses in the prepubescent females resulted in an increased number of ova. A maximum of 55 ova per mouse was reached when stimulating with 20 IU of FSH/LH; higher stimulation doses showed no further increase in oocyte recovery. In the prepubescent group, a maximal number of recovered mature ova was reached with 15 IU of FSH/LH. In the sexually mature female group, 20 IU of FSH/LH gave the best quantitative and qualitative results. Positive effects of copulation on the number and maturity of oocytes in all induction doses were more evident in the prepubescent females and these parameters were significantly more improved (P < 0.05) in this group when compared to the pubertal females. Our findings led to the conclusion that ovulation induction of prepubescent outbred BALB/c mice with 15 IU FSH/LH and sexually mature ones with 20 IU FSH/LH give the best results in terms of oocyte number and maturity.

Animals↗
PubMed2005

High-temperature fluorescent in situ hybridization for detecting Escherichia coli in seawater samples, using rRNA-targeted oligonucleotide probes and flow cytometry.

Fluorescence in situ hybridization (FISH) is a widely used method to detect environmental microorganisms. The standard protocol is typically conducted at a temperature of 46 degrees C and a hybridization time of 2 or 3 h, using the fluorescence signal intensity as the sole parameter to evaluate the performance of FISH. This paper reports our results for optimizing the conditions of FISH using rRNA-targeted oligonucleotide probes and flow cytometry and the application of these protocols to the detection of Escherichia coli in seawater spiked with E.coli culture. We obtained two types of optimized protocols for FISH, which showed rapid results with a hybridization time of less than 30 min, with performance equivalent to or better than the standard protocol in terms of the fluorescence signal intensity and the FISH hybridization efficiency (i.e., the percentage of hybridized cells giving satisfactory fluorescence intensity): (i) one-step FISH (hybridization is conducted at 60 to 75 degrees C for 30 min) and (ii) two-step FISH (pretreatment in a 90 degrees C water bath for 5 min and a hybridizing step at 50 to 55 degrees C for 15 to 20 min). We also found that satisfactory fluorescence signal intensity does not necessarily guarantee satisfactory hybridization efficiency and the tightness of the targeted population when analyzed with a flow cytometer. We subsequently successfully applied the optimized protocols to E. coli-spiked seawater samples, i.e., obtained flow cytometric signatures where the E. coli population was well separated from other particles carrying fluorescence from nonspecific binding to probes or from autofluorescence, and had a good recovery rate of the spiked E. coli cells (90%).

Escherichia coli↗
PubMed2006

Experimental validation of an inverse heat transfer algorithm for optimizing hyperthermia treatments.

Hyperthermia is a cancer treatment modality in which body tissue is exposed to elevated temperatures to destroy cancerous cells. Hyperthermia treatment planning refers to the use of computational models to optimize the heating protocol with the goal of isolating thermal damage to predetermined treatment areas. This paper presents an algorithm to optimize a hyperthermia treatment protocol using the conjugate gradient method with the adjoint problem. The output of the minimization algorithm is a heating protocol that will cause a desired amount of thermal damage. The transient temperature distribution in a cylindrical region is simulated using the bioheat transfer equation. Temperature and time are integrated to calculate the extent of thermal damage in the region via a first-order rate process based on the Arrhenius equation. Several validation experiments are carried out by applying the results of the minimization algorithm to an albumen tissue phantom. Comparisons of metrics describing the damage region (the height and radius of the volume of thermally ablated phantom) show good agreement between the desired extent of damage and the measured extent of damage. The sensitivity of the bioheat transfer model and the Arrhenius damage model to their constituent parameters is calculated to create a tolerable range of error between the desired and measured extent of damage. The measured height and radius of the ablated region fit well within the tolerable range of error found in the sensitivity analysis.

Algorithms↗
PubMed2004

Effects of dynamic compressive loading on chondrocyte biosynthesis in self-assembling peptide scaffolds.

Dynamic mechanical loading has been reported to affect chondrocyte biosynthesis in both cartilage explant and chondrocyte-seeded constructs. In this study, the effects of dynamic compression on chondrocyte-seeded peptide hydrogels were analyzed for extracellular matrix synthesis and retention over long-term culture. Initial studies were conducted with chondrocyte-seeded agarose hydrogels to explore the effects of various non-continuous loading protocols on chondrocyte biosynthesis. An optimized alternate day loading protocol was identified that increased proteoglycan (PG) synthesis over control cultures maintained in free-swelling conditions. When applied to chondrocyte-seeded peptide hydrogels, alternate day loading stimulated PG synthesis up to two-fold higher than that in free-swelling cultures. While dynamic compression also increased PG loss to the medium throughout the 39-day time course, total PG accumulation in the scaffold was significantly higher than in controls after 16 and 39 days of loading, resulting in an increase in the equilibrium and dynamic compressive stiffness of the constructs. Viable cell densities of dynamically compressed cultures differed from free-swelling controls by less than 20%, demonstrating that changes in PG synthesis were due to an increase in the average biosynthesis per viable cell. Protein synthesis was not greatly affected by loading, demonstrating that dynamic compression differentially regulated the synthesis of PGs. Taken together, these results demonstrate the potential of dynamic compression for stimulating PG synthesis and accumulation for applications to in vitro culture of tissue engineered constructs prior to implantation.

Animals↗
PubMed1994

MR arthrography of the shoulder with gadopentetate dimeglumine: influence of concentration, iodinated contrast material, and time on signal intensity.

OBJECTIVE: MR arthrography of the shoulder with gadopentetate dimeglumine has been proved to be valuable in the diagnosis of injuries of the rotator cuff and glenoid labrum. To date, no standard protocol for the concentration of gadopentetate dimeglumine and the volume of iodinated contrast material used for intraarticular injection exists. This study compared the intraarticular signal intensities achieved with three different MR arthrography protocols with respect to the volume of iodinated contrast material, the concentration of gadopentetate dimeglumine, and the interval between injection of contrast material and the MR study. SUBJECTS AND METHODS: MR arthrography was performed with three different protocols in 38 patients (26 men, 12 women). Patients examined with protocol 1 received an intraarticular injection of 5 ml of iotrolan and 5 ml of a 5 mmol/l solution of gadopentetate dimeglumine, resulting in a gadopentetate dimeglumine concentration of 2.5 mmol/l. Patients in protocol 2 received only 0.5 ml of iotrolan plus 12 ml of a 10 mmol/l solution of gadopentetate dimeglumine, leading to a 10 mmol/l concentration. The interval between injection and MR imaging for patients in protocols 1 and 2 was 30-45 min. Patients in protocol 3 received an intraarticular injection of 10 ml iotrolan and 1 ml of a 500 mmol/l solution of gadopentetate dimeglumine, resulting in an intraarticular concentration of gadopentetate dimeglumine of 45 mmol/l. MR examinations were performed between 20 and 360 min after administration of contrast material. Patients in protocol 3 had additional conventional and CT arthrography within 30 min after injection. The contrast-to-noise ratio of the intraarticular signal intensity was calculated for all protocols. RESULTS: The contrast-to-noise ratio (mean +/- SD) was 22.7 +/- 7.4 for the 2.5 mmol/l solution (protocol 1), 47.5 +/- 11.9 for the 10 mmol/l solution (protocol 2), and 9.9 +/- 3.1 for the 45 mmol/l solution (protocol 3) within 1 hr after injection. For protocol 3, an increase in contrast-to-noise ratio was observed after 90-180 min (53.5 +/- 12.7), followed by a decrease in contrast-to-noise ratio after 180 min (17.1 +/- 8.2). The image quality of conventional, CT, and MR arthrography (90-180 min after injection) was good in all cases of protocol 3. CONCLUSION: For MR arthrography performed within 1 hr after injection, protocol 2 is sufficient. The optimal time frame for protocol 3 is between 1.5 and 3 hr after joint puncture. Protocol 3 allows the prior performance of conventional and CT arthrography. Therefore, the addition of 1 ml of a 500 mmol/l solution of gadopentetate dimeglumine to 10 ml of iodinated contrast material is advisable if a subsequent MR study is anticipated.

Adult↗
PubMed2006

Stability of a practical measure of recovery from resistance training.

McLester et al. (2003) proposed a practical protocol to determine optimal recovery times between resistance training workouts. For this protocol to be useful, it must be stable. The purpose of this study was to investigate the stability of that protocol. College-aged resistance trained men (n = 10) performed 3 sets to volitional failure using a 10-repetition maximum load for 6 exercises. Recovery was evaluated on 4 occasions by the number of repetitions performed for each individual exercise after recovery periods of 48, 72, 96, and 120 hours in counterbalanced order. To evaluate stability, this procedure was performed twice. The number of repetitions after each recovery interval were compared with initial baseline performances. A priori, adequate stability was defined as 70% of the participants achieving similar recovery duration on both trials. Pooled repetitions over all 6 exercises indicated that 80% of participants returned to baseline strength levels after the same recovery duration for both trials. However, when individual muscle group repetition performance was evaluated, stability varied from 20 to 70%. Variability in rest, nutrition, prior activity, and other factors probably induced instability in individual strength measures, but not sufficiently to influence the aggregate results. Some muscle groups may have greater sensitivity to variations in ecological factors such as these. We believe that the tested protocol may be useful in establishing recovery times for multimuscle group workouts, but not stable enough to be useful in establishing recovery times for individual muscle groups.

Adult↗
PubMed2005

Sestamibi scans are not all created equally.

HYPOTHESIS: The sensitivity of sestamibi scanning techniques used for preoperative localization in primary hyperparathyroidism is a function of the parameters of image acquisition and processing. DESIGN: Criterion standard vs optimized technique. SETTING: Tertiary referral center. PATIENTS: One hundred forty-eight consecutive patients with primary hyperthyroidism were analyzed. Under the initial protocol, 97 patients underwent a preexisting standard sestamibi--single-photon emission computed tomographic scan and surgical exploration. The scanning technique was modified and in the revised protocol, 51 patients underwent imaging and surgical exploration. INTERVENTION: Image acquisition and processing revisions as follows: patient positioning standardized, collimator resolution adjusted, radioactive tracer delay extended, visualization field broadened, data extraction refined, and image processing filter modified. MAIN OUTCOME MEASURES: concordance among the scan and operative localization, lateralization, and cure rate. RESULTS: Initial protocol: 97 patients underwent surgery for primary hyperthyroidism with the initial sestamibi design. Eighty-one patients (83%) had a positive result, that is, at least 1 gland was identified; 77 patients (79%) had correct lateralization; and 49 patients (52%) had precise localization. Revised protocol: 51 patients underwent imaging under the optimized protocol. Forty-nine patients (96) had a positive result; 47 patients (92%) had correct lateralization; and 36 patients (70%) had precise localization. These improvements were significant, with P<.05 for localization and P<.01 for lateralization. Cure rates were 96% in both groups, confirmed by laboratory and pathologic findings. CONCLUSIONS: Sestamibi optimization in primary hyperparathyroidism can improve scan sensitivity. This may permit a focused minimally invasive operation.

Chi-Square Distribution↗
PubMed2006

Use of surface enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS) to study protein expression in a rat model of cocaine withdrawal.

Surface enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS) is an analytical technology for proteomic analysis that combines chromatography and mass spectrometry. At present, this technology is most commonly being exploited for the simultaneous measurement of numerous proteins in serum, but has also been utilized in organ tissue, although rarely in the brain. We applied SELDI-TOF MS technology to study protein expression in the brain of rats withdrawn from repeated cocaine exposure. Our goals were to optimize sample preparation and ProteinChip Array protocols for brain tissue, to verify the reproducibility of SELDI-TOF mass spectra and to determine whether SELDI-TOF MS detects differentially expressed proteins in cocaine- versus saline-treated rats. Consequently, we have developed an optimal protocol and generated a reproducible spectral pattern with six dominant peaks in all test samples. We have detected two smaller peaks (m/z: 5179, 5030) that were significantly increased (p < 0.05) in cocaine-treated rats compared to saline-treated rats. In summary, the application of SELDI-TOF MS to the study of protein expression in a rat model of cocaine withdrawal is feasible and has the potential to generate new hypotheses.

Animals↗
PubMedDate not supplied

Cryopreservation of shoot apices of in-vitro grown gentian plants: comparison of vitrification and encapsulation-vitrification protocols.

Using vitrification and encapsulation-vitrification protocols, we successfully cryopreserved shoot apices from in-vitro plants of different Gentiana cultivars (lines). Although both protocols gave high survival percentages after storage in liquid nitrogen, the encapsulation-vitrification protocol had several distinct advantages over the vitrification protocol: (i) survival was higher under optimal conditions, (ii) the range of optimal exposure periods to the plant vitrification solution 2 (PVS2) was broader, and (iii) regrowth of cryopreserved shoot apices was apparently more vigorous and faster. Shoot apices from ten cultivars/lines of three Gentiana species (G. scabra, G. triflora, and G. pneumonanthe) were successfully cryopreserved using the two protocols with average survival of 49.0 percent and 73.7 percent for vitrification and encapsulation-vitrification, respectively. These results indicate that the two protocols optimized in the present study are promising for cryopreservation of a wide range of Gentiana genetic resources.

Cryopreservation↗
PubMed2001

Optimization of automatic bolus tracking for timing of the arterial phase of helical liver CT.

The aim of this study was to optimize bolus tracking for timing of the arterial phase of biphasic helical liver CT and to compare optimized bolus tracking to a standard delay. One hundred fifty patients were examined with six protocols: 5- or 10-s delay after triggering at a threshold of 50 or 75 or 100 HU enhancement in the aorta at the origin of the celiac arteries after injection of 120 ml contrast material at 3 ml/s. Optimal arterial enhancement was defined as 20-30% of hepatic enhancement in portal venous phase. Another 50 patients were examined with the optimized protocol and compared to 50 gender- and age-matched patients who underwent a 25-s standard delay. A 10-s delay after the 75-HU threshold resulted in the most patients with an optimal arterial phase (p < 0.01). Thirty-one of 75 patients examined with this protocol showed optimal early liver enhancement. Bolus tracking compared with standard delay revealed only a trend for a difference (p = 0.07). The outcome of automatic bolus tracking differs depending on the protocol used; however, optimal arterial phase imaging was seen in only 41% of patients, indicating only a trend for superior timing compared with a standard delay.

Adolescent↗