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PubMed1994

Third-generation hepatitis C virus tests in asymptomatic anti-HCV-positive blood donors.

This study evaluated the performance of third-generation anti-HCV assays in blood donors who were positive by second-generation anti-HCV, and assessed any possible relationship between antibody patterns, HCV replication and liver damage. Fifty-two second-generation enzyme immunoassay-positive asymptomatic Italian blood donors were retested for anti-HCV by third-generation enzyme immunoassay and recombinant immunoblot assay (Ortho third-generation enzyme immunoassay, third-generation recombinant immunoblot assay), utilising recombinant C33c and NS5 and synthetic peptide C100 and C22 antigens, and for HCV-RNA by "nested" polymerase chain reaction with 5' region primers. Alanine aminotransferases were tested monthly for 6 months. Two out of 52 second-generation enzyme immunoassay-positive donors were third-generation enzyme immunoassay, third-generation recombinant immunoblot assay and HCV-RNA negative. Among 50 third-generation enzyme immunoassay-positive cases, two had a third-generation enzyme immunoassay optical density < or = 1: one was third-generation recombinant immunoblot assay and HCV-RNA negative, and the other was third-generation recombinant immunoblot assay "indeterminate" and HCV-RNA-positive. The remaining 48 cases had third-generation enzyme immunoassay optical density > 1: six were third-generation recombinant immunoblot assay negative (one HCV-RNA+ve), eight "indeterminate" (two HCV-RNA+ve) and 34 positive (22 HCV-RNA+ve). All "indeterminate" subjects reacted only to C22. HCV-RNA was positive in 22/34 cases with positive third-generation recombinant immunoblot assay (two or more Ags), 3/9 "indeterminate" and 1/11 negative. Alanine amino-transferases were abnormal in 13 cases with positive third-generation recombinant immunoblot assay, one was "indeterminate" and three were negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Left and right basal ganglia and frontal activity during language generation: contributions to lexical, semantic, and phonological processes.

fMRI was used to determine the frontal, basal ganglia, and thalamic structures engaged by three facets of language generation: lexical status of generated items, the use of semantic vs. phonological information during language generation, and rate of generation. During fMRI, 21 neurologically normal subjects performed four tasks: generation of nonsense syllables given beginning and ending consonant blends, generation of words given a rhyming word, generation of words given a semantic category at a fast rate (matched to the rate of nonsense syllable generation), and generation of words given a semantic category at a slow rate (matched to the rate of generating of rhyming words). Components of a left pre-SMA-dorsal caudate nucleus-ventral anterior thalamic loop were active during word generation from rhyming or category cues but not during nonsense syllable generation. Findings indicate that this loop is involved in retrieving words from pre-existing lexical stores. Relatively diffuse activity in the right basal ganglia (caudate nucleus and putamen) also was found during word-generation tasks but not during nonsense syllable generation. Given the relative absence of right frontal activity during the word generation tasks, we suggest that the right basal ganglia activity serves to suppress right frontal activity, preventing right frontal structures from interfering with language production. Current findings establish roles for the left and the right basal ganglia in word generation. Hypotheses are discussed for future research to help refine our understanding of basal ganglia functions in language generation.

Adolescent↗
PubMed2005

Global generations: social change in the twentieth century.

The concept of generation within sociology has until recently been a marginal area of interest. However, various demographic, cultural and intellectual developments have re-awakened an interest in generations that started with the classic essay by Karl Mannheim. To date, the sociological literature has generally conceptualized generations as nationally bounded entities. In this paper we suggest that the sociology of generations should develop the concept of global generations. This conceptual enhancement is important because the growth of global communications technology has enabled traumatic events, in an unparalleled way, to be experienced globally. The late nineteenth and early twentieth century was the era of international generations, united through print media, and the mid-twentieth century saw the emergence of transnational generations, facilitated by new broadcast communications. However, the latter part of the twentieth century is the period of global generations, defined by electronic communications technology, which is characterized, uniquely, by increasing interactivity. The 1960s generation was the first global generation, the emergence of which had world-wide consequences; today with major developments in new electronic communications, there is even more potential for the emergence of global generations that can communicate across national boundaries and through time. If in the past historical traumas combined with available opportunities to create national generations, now globally experienced traumas, facilitated by new media technologies, have the potential for creating global generational consciousness. The media have become increasingly implicated in the formation of generational movements. Because we are talking about generations in the making rather than an historical generation, this article is necessarily speculative; it aims to provoke discussion and establish a new research agenda for work on generations.

Cohort Effect↗
PubMed2002

[Generative potential in advanced age. Sociological intergenerational considerations of an old topic].

The concept of generativity--at first related to middle age--is increasingly used to describe developmental processes at higher ages. In previous discussions, however, the concept of generativity has been used without clear references either to stages in later life (independent retirement versus dependent old age) or to different concepts of generations. A stage-oriented approach--based on ideas developed by Margret Baltes--indicates that the dimensions of generativity change with aging (more active generativity for younger retired people, more passive and compensating generativity among fragile and dependent persons). A generational approach--looking at different concepts of generations (family generations, societal generations, welfare generations)--shows that generativity within family generations is underlined by social norms, whereas generativity concerning welfare generations or societal generations remains an unstructured or even anomic developmental task.

Activities of Daily Living↗
PubMed2000

Comparison of first- and second-generation prostheses for endoluminal repair of abdominal aortic aneurysms: a 6-year study with life table analysis.

PURPOSE: The outcome of endoluminal repair of abdominal aortic aneurysms with two generations of prostheses was analyzed and compared. METHODS: Between May 1992 and December 1998, 266 patients underwent elective endoluminal repair of an AAA. First-generation prostheses were used in 118 patients (group I), and second-generation prostheses were used in 148 patients (group II). The two groups were similar in age, sex, and size of AAA. The proportion of patients with comorbidities was higher in group I than in group II, but not significantly. First-generation devices were characterized by large (24F internal diameter) delivery systems, one-piece construction, and a lack of metallic support throughout their length. Second-generation devices had smaller (21F or smaller internal diameter) delivery systems, modular construction, and a metallic frame throughout the length of the prostheses. The major end-point criteria were survival and successful endoluminal repair. Success was defined as the exclusion of the aneurysm sac from the circulation, with stability or the reduction in AAA maximum transverse diameter. Persistent endoleaks were classified as failures, irrespective of whether they were subsequently corrected by means of secondary endovascular intervention. The minimum follow-up period was 5 months for each of the 266 patients. Analysis was performed by means of the life-table method. RESULTS: Perioperative mortality was not significantly different between group I (4.2%) and group II (2.7%). There was a statistically significant difference between the survival curves of the two generations, which favored group II (P =.012). There was a significant (P <.001) difference between the two generations of patients in their conditional probability of graft failure when the competing risk of all-cause mortality was considered. Second-generation patients were at a lower risk of graft failure than first-generation patients. The probability of failure, expressed as a proportion of grafts failing at 2 years, was 0.15 for patients with second-generation prostheses and 0.33 for patients with first-generation prostheses. CONCLUSION: Endoluminal AAA repair is a safe procedure, whether first- or second-generation prostheses are used. Survival and probability of graft success were significantly higher with second-generation prostheses than with first-generation prostheses. This improvement in outcome resulted from a combination of increasing clinical experience and advances in technology. A more accurate evaluation of the role of the endoluminal method in AAA repair would be achieved by studying patients in whom second-generation devices were used, rather than longer term studies in which first- and second-generation devices were used.

Aged↗
PubMed1997

Serologic survey for control of hepatitis C in haemodialysis patients: third-generation assays and analysis of costs.

There is little information about the serologic survey for control of hepatitis C by using third-generation assays among chronic haemodialysis (HD) patients, and no analysis of costs has been made to this end. A serologic survey for control of hepatitis C was performed in 190 HD patients attending a single dialysis unit, using second- and third-generation assays. Costs of both serologic surveys were calculated. Anti-HCV prevalence tested by third-generation assays increased from 25% (48/190) to 28% (53/190) compared to second-generation testing; 56% (9/16) of patients showing uncertain findings by second-generation tests gave unequivocal results by third-generation assays; median duration of HD treatment and raised aminotransferase levels were positively associated (P = 0.004 and P = 0.012, respectively) with anti-HCV detected by third-generation assays. The serologic survey for control of hepatitis C in HD patients at our centre was slightly more expensive by third-generation assays compared to second-generation testing (US$18866 vs US$17200 per year). In summary, the use of third-generation tests largely clarified the uncertain results of second-generation tests; new additional positive patients were detected by third-generation assays compared to second-generation testing. Third-generation assays showed the association of duration of HD treatment and raised aminotransferase levels with anti-HCV antibody, as previously found by first- and second-generation assays. To date, third-generation screening and confirmatory assays seem extremely useful in the serologic survey for control of hepatitis C in HD centres without a considerable outlay.

Adult↗
PubMed2006

Vascular complications with newer generations of angioseal vascular closure devices.

OBJECTIVES: To evaluate the safety and efficacy of newer generations of a single vascular closure device (VCD), Angioseal, compared to contemporaneous manual compression. BACKGROUND: Previous assessment of VCD safety and efficacy has been based primarily on outcomes associated with the original VCD. Few data exist comparing safety and efficacy of modifications of the original VCDs. METHODS: We evaluated in-hospital outcomes of patients undergoing diagnostic cath and percutaneous coronary intervention at a single center: 3,898 with manual compression and 3,898 with the Angioseal VCD. Three generations of the Angioseal device were studied: Generation 1, 7/97-4/00; Generation 2, 5/00-6/02; and Generation 3, 7/02-12/03. Propensity analysis was used to match patients within each generation for clinical and procedural covariates. RESULTS: Closure success was 98.5% for Generation 1, 98.6% for Generation 2, and 98.1% for Generation 3, P = NS. The odds ratio for any vascular complication comparing Angioseal to manual compression was 0.92 (0.42-2.01) for Generation 1; 0.83 (0.49-1.41) for Generation 2; and 0.75 (0.32-1.77) for Generation 3. Multivariate logistic regression identified closure success and Angioseal device Generation 3 versus Generation 1 as predictive of reduced vascular complications during the entire study period. CONCLUSION: These data indicate that the newest generation of the Angioseal VCD is at least as effective as the original device. Moreover, use of the Angioseal VCD was associated with vascular complications similar to or lower than vascular complications following manual compression for each generation of Angioseal device analyzed.

Angioplasty, Balloon, Coronary↗
PubMed2002

Surveillance of TSH-suppressive levothyroxine treatment in thyroid cancer patients: TRH testing versus basal TSH determination by a third generation assay.

OBJECTIVE, DESIGN AND METHODS: Although TRH testing has been eliminated in the diagnosis of most benign thyroid diseases, it is still controversial whether or not it can be replaced by ultrasensitive determination of basal TSH for monitoring optimal TSH suppression in thyroid cancer patients. We compared basal and TRH-stimulated TSH values measured by a 2 nd generation assay (lower detection limit 0.1 mU/l) and by a 3 rd generation assay (lower detection limit 0.005 mU/l) in 209 thyroidectomized thyroid cancer patients under suppressive levothyroxine treatment. RESULTS: In the 2 nd generation assay all patients had basal TSH values < 0.1 mU/l (criterion of admission in the study), and the TRH-stimulated TSH values were above the lower detection limit in 47% of the patients (range < 0.1-1.0 mU/l). In the 3 rd generation assay TSH was above the lower detection limit in 67% under basal conditions (range < 0.005-0.098 mU/l), and in 83% after TRH stimulation (range < 0.005-1.000 mU/l). We observed close correlations (p < 0.001) between basal and TRH-stimulated TSH in the 3 rd generation assay (r = 0.86), between TRH-stimulated TSH in the 2 nd and 3 rd generation assay (r = 0.95), and between TRH-stimulated TSH in the 2 nd generation assay and basal TSH in the 3 rd generation assay (r = 0.73). The ratio between TRH-stimulated and basal TSH values was in the average range 7-9 : 1. Subdividing the patients in three subgroups based on the TRH-stimulated TSH values from the 2 nd generation assay, the corresponding basal TSH values (median and [25.-75. percentile]) from the 3 rd generation assay were < 0.005 [< 0.005-0.010] mU/l in subgroup A (2 nd generation stim. TSH: < 0.15 mU/l), 0.032 [0.021-0.040] mU/l in subgroup B (2 nd generation stim. TSH: 0.15-0.4 mU/l), and 0.066 [0.046-0.085] mU/l in subgroup C (2 nd generation stim. TSH: > or = 0.5 mU/l). CONCLUSIONS: Even in those thyroid cancer patients where a high degree of TSH suppression is the therapeutic goal, 3 rd generation TSH assays enable a reliable adjustment of the levothyroxine dose by basal TSH determinations. In laboratories still using 2 nd generation assays, the monitoring of maximal TSH suppression in patients with high-risk thyroid cancer should be performed by TRH testing.

Adolescent↗
PubMed1980

The refurbished pulse generator.

With the advent of long-life lithium pulse generators, normally functioning pulse generators with a potential life of more than five years have been removed from patients and become available for re-implantation. Although pulse generator refurbishing is widely employed, the practice has not been accepted in the United States. At The Royal Melbourne Hospital, all lithium pulse generators removed because of patient death or other causes were washed in a quaternary ammonium compound and soaked in formaldehyde. Pulse generators were than electronically tested and, if within specification, were made available for re-implantation. Pulse generators were then washed under sterile conditions in distilled water and gas-sterilized with ethylene oxide. Between 1975 and 1978 (48 months), 600 pulse generators were implanted and 93 pulse generators removed. There were 56 deaths, 22 cases of pre-erosion, erosion, or infection and 15 elective removals either due to lead problems or impending power source depletion. Eight-three (89%) pulse generators were refurbished (14% of total implants). This included 12 pulse generators refurbished on two occasions. Ten pulse generators were returned to manufacturers, seven because of impending power source depletion, two with suspected electronic faults, and one with a damaged case. Two complications occurred in patients with refurbished pulse generators. An infective process present with the previous pulse generator spread to a new pocket. The other pulse generator was removed 35 months post second implantation because of impending power source depletion. Primary infection or unusual tissue reactions did not occur. Pulse generator refurbishing as described was found to be a safe and economic procedure.

Electric Power Supplies↗
PubMedDate not supplied

Comparison of single-phase and high-frequency generators for x-ray units.

The purpose of this study was to compare characteristics and performances between single-phase (SP) and high-frequency (HF) generators for x-ray units dedicated to veterinary radiology practice. A 30-kW SP and a 30-kW high HF generator connected to a rotating anode x-ray tube were used for the study. Source-film distance, screen/film combination, and film processing were kept the same during the experiment. The mAs value yielding a similar film optical density of a stair step phantom, as assessed by a densitometer and a similar dose, as assessed by a solid state detector, was estimated for different kVp values. The ratio of the mAs used with the SP generator to the equivalent mAs used with the HF generator to produce similar film density or radiation dose was calculated. Subject contrast was measured for different kVp values as the relative difference in film optical density between two steps of the phantom. The waveform of the tube current was recorded for the two generators using an oscilloscope. Motion artifact was produced on a lateral radiograph of a canine tarsus using the two generators. Reproducibility was assessed by comparing the variances of film density measurements made on the central step of the phantom on 10 consecutive images produced with the two generators. mAs ratios (SP/HF) to obtain similar film optical density ranged from 2 (for 90kVp) to 2.5 (for 70 kVp), and mAs ratios to obtain similar radiation dose ranged from 1.2 (for 100 kVp) to 1.4 (for 70 kVp). Image contrast was slightly higher for the SP than for the HF generator. Current waveform for the SP generator was half-sinusoidal and it was almost continuous for the HF generator. Motion artifact appeared as blur for the HF generator and as several regularly placed images of the subject for the SP generator. Reproducibility was significantly better for the HF than for the SP generator (P = 0.047). It was concluded that the HF generator was approximately two times more efficient, had a better reproducibility, and produced images with a lower contrast than the SP generator. Motion artifact appears differently due to different current waveform.

Animals↗
PubMed1978

L-triiodothyronine and L-reverse-triiodothyronine generation in the human polymorphonuclear leukocyte.

Extrathyroidal monodeiodination of l-thyroxine (T(4)) is the principal source of l-triiodothyronine (T(3)) and l-reverse-triiodothyronine (rT(3)) production. To define some of the cellular factors involved, we examined T(3) and rT(3) generation from added nonradioactive T(4) in human polymorphonuclear leukocytes, using radioimmunoassays to quantify the T(3) and rT(3) generated. Under optimum incubation conditions which included a pH of 6.5 in sucrose-acetate buffer, the presence of dithiothreitol as a sulfhydryl-group protector, and incubation in an hypoxic atmosphere, significant net generation of T(3) and rT(3) was observed. Of the several subcellular fractions studied, the particulate fraction obtained by centrifugation at 27,000 g was found to possess the highest T(3)- and rT(3)-generating activities per unit quantity of protein. With respect to T(3) generation from substrate T(4), the K(m) was 5 muM and the V(max) was 7.2 pmol/min per mg protein. Propylthiouracil, methimazole, and prior induction of phagocytosis inhibited both T(3) and rT(3) generation, but T(3) generation was inhibited to a greater extent. rT(3), in a concentration equimolar to that of substrate T(4), did not alter T(3) generation, but inhibited T(3) generation when the molar ratio of rT(3) to T(4) approached 10:1. Under the incubation conditions employed, particulate fractions of leukocytes obtained from five cord blood samples displayed an essentially normal relationship between T(3)- and rT(3)-generating activities, despite the distinctly divergent serum T(3) and rT(3) concentrations in these samples. From our findings, we draw the following conclusions: (a) the human polymorphonuclear leukocyte possesses the ability to generate T(3) and rT(3) from substrate T(4); (b) the T(3)- and rT(3)-generating activities are associated principally with the 27,000 g particulate fraction and display enzymic characteristics with a sulfhydryl-group requirement; (c) T(3)-generating activity appears to be more susceptible to inhibitory influences than rT(3)-generating activity; and (d) in cord blood leukocytes, the putative enzymes catalyzing T(3) and rT(3) generation appear to be functionally intact under the experimental conditions employed.

Adult↗
PubMed2000

Performance of a 62Zn/62Cu generator in clinical trials of PET perfusion agent 62Cu-PTSM.

UNLABELLED: The 62Zn/62Cu PET generator can be inexpensively produced and distributed from a single production site operating under typical good manufacturing practice guidelines. It therefore has the potential to greatly facilitate development of clinically practical PET. We report generator performance in a study in which 62Cu-pyruvaldehyde-bis(n4-methylthiosemicarbazone (PTSM) myocardial perfusion imaging is compared with 99mTc-sestamibi in the diagnosis of coronary artery disease. The 62Zn/62Cu generator is an improved version of a previously reported system that employs automated synthesis of 62Cu-PTSM. With this approach, the cumbersome step of 18C purification has been eliminated. METHODS: The 62Zn (9.3 h half-life) parent isotope is prepared by proton bombardment of natural copper at 33 MeV. A typical target irradiated with 37.5 microA/h is delivered by 12:00 PM on the day it is to be processed. Purified 62Zn obtained from the target is loaded onto the generator column in 2 mol/L HCl. The generator is eluted using an internal three-channel peristaltic pump, which delivers 2.25 mL eluant (1.8 mol/L NaCl, 0.2 mol/L HCl) through the generator column to elute the 62Cu in 40 s. The same pump simultaneously pumps an equal volume of buffer (0.4 mol/L NaOAc) and 1 mL ligand solution (2 ppm PTSM, 2% EtOH) passing it through a septum into a 35-cc syringe preloaded with 28 mL sterile water. This solution is thoroughly mixed by agitation of the syringe and injected as a bolus through a 0.2 microm filter. The generator is eluted twice before shipping, providing quality assurance samples, and shipped to the clinical site by overnight delivery. Complete quality assurance testing is performed the evening before the generator reaches the clinical site. RESULTS: A total of 34 generators have been produced and shipped to 2 clinical sites for a phase III Food and Drug Administration study. The load activity on the generators at 8:00 AM the day of clinical use was 1.7+/-0.2 GBq (46.7+/-5.6 mCi), and yield was 72%+/-16%. Breakthrough of 62Zn was undetectable by high-purity germanium spectroscopy for all units. Radiochemical purity was 95.4%+/-2.4%. Volume delivered, pH, sterility, and bacterial endotoxin tests yielded passing results on all generators. The entire process of generator production, from target receipt to generator shipment, took less than 6 h and cost approximately $1000, including shipping charges and cyclotron cost. A total of 68 patients were injected with 2 62Cu-PTSM doses, with a mean injected activity of 0.8+/-0.2 GBq (20.5+/-5.3 mCi) with no adverse side effects. CONCLUSION: Results of this work confirm that the 62Zn/62Cu generator is an easily produced, transportable, and inexpensive source of PET radiopharmaceuticals, which can expand the field of clinical PET imaging by providing radiopharmaceuticals to sites not associated with cyclotrons.

Clinical Trials, Phase III as Topic↗