Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

184 Effect of selenium on the differentiation of porcine adipose-derived stem cells into osteoblasts

Bone damage is a common occurrence and although traditional bone healing methods work well, they are not always able to fix all issues pertaining to the injury. However, recent research on stem cell therapies using adipose-derived stem cells (ASC) has shown that ASC that differentiate into osteoblasts can be used as a potentially better solution for bone injuries. Selenium is a nutritional trace element that has been found to be essential in the production of selenoproteins and bone growth. Selenium plays an integral role in osteoblast cell differentiation and proliferation. The aim of this experiment was to test whether adding selenium to osteogenic influences the differentiation potential of ASC into osteoblasts. Porcine ASC were isolated as described (Monaco et al. 2009, Open Tissue Eng. Regen. Med. J. 2, 20-33). Seven different treatments were given to the cells: a negative control of DMEM, a positive control of osteogenic medium, and 5 concentrations of selenium in the osteogenic medium (10, 5, 1, 0.5, and 0.1 µM). Medium was changed twice a week for 4 weeks, at the end of which the cells were stained with Alizarin Red S stain. The number of osteoblastic nodules in each well were counted and divided into the categories of “forming” and “formed.” A generalized linear model (GLM) procedure (SPSS Inc./IBM Corp., Chicago, IL, USA) was used to analyse the data. The least statistical difference (l.s.d.) post hoc test was used to perform statistical multiple comparison with an α-level of 0.05. The results showed (Table 1) that medium containing selenium concentrations of 0.1, 0.5, and 1.0 µM were able to develop more nodules than the osteogenic medium. There was no statistical difference in the total amount of forming and formed nodules in those 4 groups; however, there was a statistical tendency for a difference (P=0.06) between the medium with 1 µM selenium and the osteogenic medium. Medium containing 10 or 5 µM selenium had lower nodule counts (both forming and formed) than osteogenic medium. There was no statistical difference between 10 µM and DMEM. These results suggest that low concentrations of selenium have a positive effect on nodule formation, whereas higher concentrations are detrimental. Table 1.The average number (standard deviations in parentheses) of formed, forming, and total osteoblastic nodules in each of the different treatments

208 The effect of copper on the differentiation of adipose-derived stem cells into osteoblasts

Large bone defects present a tremendous challenge to the treating surgeon. Tissue engineering using scaffolds of various sizes and shapes that contain stem cells and other osteoinductive molecules offer a potential solution to this difficult problem. The aim of this project was to evaluate whether osteogenic medium infused with copper influences the differentiation of adipose-derived stem cells (ASC) into osteoblasts. Copper is a key cofactor for lysyl oxidase, an enzyme involved in producing a collagen matrix through which bone can grow. Lysyl oxidase expression is up-regulated in bone marrow stromal cells (Khosravi et al. 2014 PLoS One 9, e100669). Our hypothesis was that the presence of copper in the osteogenic medium would positively influence the number of osteoblastic nodules formed. Swine ASC were isolated as described (Monaco et al. 2009 Open Tissue Eng. Regen. Med. J. 2, 20-33). The ASC were divided in 7 different treatments: 5 concentrations of copper in the osteogenic medium (0.1, 1, 10, 50, and 100 µM) plus 2 control treatments (osteogenic medium without copper and a negative control, DMEM). The medium was changed twice a week for 4 weeks. The experiment was replicated 6 times. At the end of the culture period, cells were stained with Alizarin Red S and Von Kossa stains. In each well, we counted the total number of nodules that were either formed or forming. Data were analysed using the generalized linear model (GLM) procedure (SPSS Inc./IBM Corp., Armonk, NY). The least significant difference (l.s.d.) post hoc test was used to perform statistical multiple comparison. The α-level was set at 0.05. The results showed that more nodules were formed in the 0.1 and 1 µM copper groups compared with the osteogenic control, but there was no statistical difference between those 2 treatments. Table 1 illustrates the total number of formed and forming nodules in addition to their standard deviation. There was a positive effect on nodule formation when copper concentrations of 0.1 and 1 µM were added to the osteogenic medium. In contrast, copper concentrations of 50 and 100 µM had a cytotoxic effect. These results confirm that low concentrations of copper have a positive effect on osteogenesis. This preliminary experiment is the first step towards the analysis of the behaviour of ASC on scaffolds with copper incorporated into their matrix. Table 1.The average number (standard deviations in parentheses) of total formed and forming osteoblast nodules compared between treatment groups

Childhood, adolescent, and young adult cancer survivors (CAYACS) research program of British Columbia: Data linkage: Results to date

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Background: Long-term survivors of childhood and adolescent cancers are at risk for late mortality and morbidity. Using database linkages we assessed the extent of these issues and health care utilization in a population based cohort in British Columbia. Methods: Retrospective cohorts of 3,483 survivors (>5 years from diagnosis), and representative comparison groups, have been identified from population-based registries. Linkages were made with administrative databases of risk factors and outcomes. Late mortality, second cancers, late morbidity, health services utilization, continuity of care, and educational outcomes, among those diagnosed before age 20 between 1970 to 1995, and followed to 2000, have been examined. Results: Survivors experienced a 9-fold increase in mortality (SMR 9.1, 95% CI 7.8–10.5). Risk of developing a second cancer was 5 times higher than in the general population (SIR 5.0, 95% CI 3.8–6.5). Survivors had three times the odds of being hospitalized (OR 2.97, 95% CI 2.56–3.45) in a three-year period (1998–2000). Survivors were significantly more likely than the population group to consult any physician (excluding oncologists) (adj. RR 1.61, 95% CI 1.51–1.70). Survivors were found to experience a drop in continuity of primary health care as they aged and transitioned into adult care. Survivors were significantly more likely than their peers to receive special education (32.5% vs. 14.1%), most significantly among CNS survivors who received cranial irradiation. Conclusions: Survivors of childhood and adolescent cancers have severe long term health issues and increased health care utilization. Survivors of CNS tumors were at highest risk of poor health and educational outcomes measured. Data linkage provides useful insights for survivorship research.

No significant financial relationships to disclose.

[Opioids in musculoskeletal pain]

Opioids are the most potent analgesics available and are well established for the treatment of severe acute, surgical and cancer pain. Due to their high effectiveness, their use in chronic non-cancer pain (CNCP) is being propagated. However, the use of opioids is still controversial due to their side effects, such as tolerance, addiction or withdrawal, and administrative difficulties associated with their prescription. Chronic rheumatic diseases, in particular low back pain and arthritis, are the leading causes of CNCP. The present article provides a brief overview of the role of opioids in chronic rheumatic diseases, pointing out that a national guideline for opioid use in CNCP is expected at the end of 2008. Furthermore, the peripheral effects of opioids on pain and inflammation in rheumatic diseases will be outlined.

Gemcitabine and vinorelbine in advanced nonsmall cell lung carcinoma: a phase II study

BACKGROUND

The authors conducted a Phase II study to evaluate the activity of the combination of gemcitabine and vinorelbine in patients with advanced nonsmall cell lung carcinoma (NSCLC).

METHODS

Patients were eligible if they had Stage IIIB (malignant pleural effusion) or Stage IV NSCLC, no prior chemotherapy, and Cancer and Leukemia Group B performance status (PS) 0-2. Patients with brain metastases were eligible if they were neurologically stable after brain irradiation. Thirty-three patients from participating institutions were enrolled. One patient was ineligible due to untreated brain metastases. Patients were treated with gemcitabine 1250 mg/m(2) over 30 minutes (1000 mg/m(2) for the first 6 patients) and vinorelbine 25 mg/m(2) over 6 minutes, both administered intravenously on Days 1 and 8 every 21 days. Treatment was planned for a total of six cycles or more if the patient had persistent benefit. Growth factors were not allowed.

RESULTS

Among all 32 eligible patients, there were 8 partial responses, for an overall response rate of 25% (95% confidence interval [CI], 11.5-43. 4%). The median survival time was 8.3 months and the 1-year survival rate was 38% (95% CI, 24-59%). Patients with PS 0-1 had a median survival of 11.7 months and a 1-year survival rate of 48%. Grade 3 and 4 neutropenia was observed in 13% and 25% of the 148 treatment cycles, respectively. One patient died of neutropenic sepsis. Only 2 episodes of Grade 3 and 4 thrombocytopenia were observed. Nonhematologic toxicity was minimal.

CONCLUSIONS

Gemcitabine and vinorelbine is an active and well-tolerated regimen in patients with advanced NSCLC, with response and survival rates at least comparable to those achieved with standard platinum-based regimens. This combination may be particularly suitable for the elderly or for patients who cannot tolerate more toxic platinum-based regimens.

A replication study of obsessional followers and offenders with mental disorders

The purpose of this study was to compare certain demographic, clinical, and criminal variables within subgroups of obsessional followers, and compare them to a group of offenders with mental disorders to attempt to replicate earlier findings. A static group archival design utilized a non-random group of convenience and a randomly selected comparison group. Sixty-five obsessional followers and 65 offenders with mental disorders were evaluated by psychiatrists and psychologists for court ordered reasons during their criminal proceedings. Both groups were evaluated during the same period, in the same court diagnostic clinic, and generally for sentencing determinations. The obsessional followers were measured on demographic, diagnostic, pursuit, victim, threat, violence, emotional, motivational, and defense variables. Inferential comparisons that used parametric and nonparametric statistics were done within and between groups on select variables. The obsessional followers had significantly greater estimated IQ than the offenders with mental disorders, but were neither older nor better educated. There were no significant differences in the high prevalence of both DSM-IV Axis I and II diagnoses. Obsessional followers who stalked prior sexual intimates were significantly more likely to have a substance abuse or dependence diagnosis. Obsessional followers who stalked strangers or acquaintances were more likely to be delusional. The majority of the obsessional followers, primarily motivated by anger, both threatened and were violent toward person or property. The modal obsessional follower is an average or above IQ, unemployed, unmarried male in his fourth decade of life. chronically pursuing a prior sexually intimate female. He is diagnosed with substance abuse or dependence and a personality disorder NOS, and has a prior psychiatric, criminal and substance abuse history. He is angry, likely to threaten her, and assault her person or property without causing serious injury.

Stressful life events and social rhythm disruption in the onset of manic and depressive bipolar episodes: a preliminary investigation

BACKGROUND

The association between stressful life events and onset of bipolar episodes is unclear. The association between bipolar episode onset and types of life events that disrupt social routines, and potentially sleep, has not yet been investigated.

METHODS

Thirty-nine bipolar patients with primarily manic (n = 20) or depressed (n = 19) index episodes were interviewed with the Bedford College Life Event and Difficulty Schedule to determine the presence of severe events during 8-week pre-onset and control periods. All life events were also rated for degree of social rhythm disruption (SRD).

RESULTS

More bipolar subjects experienced at least 1 SRD event and severe event in the pre-onset vs control periods. When subjects were divided into those with manic or depressive onsets, the only significant pre-onset vs control difference was for manic patients with SRD events. Additionally, the proportion of subjects with a pre-onset SRD event was greater for manic than for depressed patients.

CONCLUSIONS

We found evidence that life events characterized by SRDs routines are associated with the onset of manic, but not depressive, episodes. Severe events seem to be related to onset of bipolar episodes, although it remains unclear whether severe events relate differentially to depressive and manic onsets.

Focus pay incentives on long-term results

The need to tie executive compensation to results rather than just effort or longevity has spawned the shift to performance-based objectives and the rewards for attaining them. Two consultants say that's not enough: Healthcare organizations must further induce results-oriented behavior by erasing the short-term focus that still permeates performance.

An Assessment of Psychiatric Residents' Knowledge and Attitudes Regarding ECT

Graduating psychiatric residents in the Philadelphia area were surveyed about their attitudes, training experiences, and knowledge regarding electroconvulsive therapy (ECT). Twenty-nine residents were interviewed. Although the majority of respondents expressed positive attitudes about the use of ECT, only two (7%) expressed confidence in their own ability to perform the treatment without supervision. The residents' general attitudes regarding ECT as a therapeutic modality were consistent with those of previous surveys of practicing psychiatrists. The level of knowledge of the residents interviewed was not related to reported didactic or practical experience. Significant gaps in training were noted. The need for more thorough, standardized training in ECT is discussed.

The effects of methylphenidate on levels of processing and laterality in children with attention deficit disorder

Effects of stimulant medication (methylphenidate) on levels (feature, name, semantic) of word processing by the left and right hemisphere were assessed in 31 attention-deficit-disordered children. In a double-blind procedure, same-different decisions were made to tachistoscopically presented word pairs under medication and placebo. Analysis of manual response times failed to show any negative effects of medication. Feature decisions were faster than name decisions, which were faster than semantic decisions. Methylphenidate induced a right visual field advantage (left hemisphere) for the name decision, which was interpreted as a normalization effect. The results suggest that (1) methylphenidate may selectively improve the phonological level of word processing and (2) methylphenidate's favorable therapeutic effect is produced through inhibition of excessive right hemisphere activity in response to task demands that engage the left hemisphere.

Anesthetic mishaps and the cost of monitoring: a proposed standard for monitoring equipment

Review of insurance data indicates that approximately 1.5 claims are paid per 10,000 anesthetic procedures, a conservative estimate of the incidence of preventable serious injury associated with anesthesia. Insurance data permit estimation of the premium cost for the anesthesiologist and hospital, per operating room per year, of $69,429.00. We propose the use of an enhanced monitoring standard requiring a pulse oximeter, capnograph, spirometer, halometer, automatic sphygmomanometer, breathing circuit oxygen analyzer, stethoscope, electrocardiographic monitor, and temperature monitor. We suggest that this premium cost, together with the estimate that 50% of incidents would be avoided, predicts a resultant saving of over $27,000/operating room/year, a savings equal to the entire cost of the enhanced monitoring system in approximately 8 months, or a yearly savings of over five times the annualized expense of the monitoring system. Thus, in addition to the moral imperative to monitor a patient during anesthesia to avoid injury and death, there is an economic incentive to monitor effectively.

Latency of mouse cytomegalovirus in sciatic nerve

This report describes a mammalian model for exploring the role of virus in peripheral neuropathy. Schwann cells in culture were permissive for mouse cytomegalovirus (MCMV) replication. Intraperitoneal inoculation rarely led to sciatic nerve infection. Sciatic nerves infected by direct intraneural injection produced infectious virus and contained viral antigen at 4 days postinfection (pi). Nerves taken later, at 4 to 8 weeks pi, contained no infectious virus, but MCMV was present in a latent state because culture of nerve explants reactivated virus. The findings contrast the viral permissiveness of cultured Schwann cells to the latency observed in intact peripheral nerve.

Theiler's virus in brain cell cultures: lysis of neurons and oligodendrocytes and persistence in astrocytes and macrophages

The mechanisms of persistence and of demyelination in Theiler's virus (TV)-induced chronic neurologic disease (a murine model for multiple sclerosis) are, as yet, disputed. We investigated the tropism and persistence of TV in brain cell culture to better understand the pathogenesis of this disease. Using anti-genic markers to identify specific cells in culture, we have demonstrated that TV infects, lytically, neurons and oligodendrocytes and persistently astrocytes and macrophages. These results suggest that host cell factors play a key role in the mechanism of demyelination and the persistence of TV in the nervous system.

AIDS: relationship to alcohol and other drugs

Most people who are exposed to AIDS do not get the syndrome. It seems clear that there must be cofactors. Most people with AIDS have a history of alcohol or other drug use, and many of the drugs used have been shown to suppress the immune system. The correlation between drug use and development of AIDS in several populations is striking, and it is suggested that definitive research into this possible cofactor be urgently initiated. The elimination of cofactors may present an immediate way to control this epidemic. Suggestions are made as to how and why alcohol and drug treatment professionals should become a part of this effort.

Therapy for late post infarction ventricular tachycardia

Non-sustained ventricular tachycardia (VT) in the late post myocardial infarction (MI) period (7-21 days) has been reported to be a predictor of sudden death. We suspected that patients with 3 beat VT on Holter monitoring in the late infarction period would demonstrate electrical instability at electrophysiologic studies. Forty-seven patients were identified as having at least 3 beat VT on Holter monitoring. Eighteen patients refused electrophysiologic studies or were not referred by their attending physician. The mean ejection fraction of this group was 43 +/- 16%. Eight patients have died, 3 sudden deaths in 13 +/- 5 months, a 17% incidence of sudden death. Twenty-nine patients underwent invasive electrophysiologic studies. Their mean ejection fraction was 37 +/- 7%, and 28 had inducible, 18 sustained ventricular tachycardia and 10 non-sustained VT. No complications were noted with electrophysiological testing in the post infarction patients. Using programmed electrical stimulation studies an effective antiarrhythmic agent preventing VT induction (usually experimental) could be found for each patient. After a mean follow-up of 12.5 +/- 4 months, the patient without inducible VT is alive and 26 of the 28 "inducible" patients are alive and well. Two patients died, one of stroke and one due to pump failure following a second MI. No sudden deaths were observed in this group. Two patients had breakthrough arrhythmias and were treated by alternative antiarrhythmic therapy that was also effective at the initial electrophysiologic studies. Thus, PES studies post MI are safe and may be an effective way to assess therapy for patients in the early post MI period, identified at high risk for sudden death.

Total hydrolyzable glycerol in amniotic fluid, and its relationship to fetal lung maturity

We describe an enzymic quantification of total hydrolyzable glycerol in amniotic fluid. An extract of amniotic fluid is hydrolyzed in mild alkali, without pretreatment with lipase. The resulting glycerol (some of which may be derived from trace amounts of triglyceride) is then enzymatically phosphorylated with adenosine 5'-[gamma 32P]triphosphate to yield glycerol [gamma 32P]phosphate. After removal of excess [gamma 32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. The close correlation (r = 0.96) we found between total hydrolyzable glycerol and phosphatidylglycerol indicates that the contribution of triglyceride to the value for total glycerol is inconsequential. This method is less time consuming and more precise than the method for phosphatidylglycerol.

Total hydrolyzable glycerol in amniotic fluid, and its relationship to fetal lung maturity

We describe an enzymic quantification of total hydrolyzable glycerol in amniotic fluid. An extract of amniotic fluid is hydrolyzed in mild alkali, without pretreatment with lipase. The resulting glycerol (some of which may be derived from trace amounts of triglyceride) is then enzymatically phosphorylated with adenosine 5'-[gamma 32P]triphosphate to yield glycerol [gamma 32P]phosphate. After removal of excess [gamma 32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. The close correlation (r = 0.96) we found between total hydrolyzable glycerol and phosphatidylglycerol indicates that the contribution of triglyceride to the value for total glycerol is inconsequential. This method is less time consuming and more precise than the method for phosphatidylglycerol.

An enzymic radiochemical method for determining phosphatidylglycerol in amniotic fluid

We describe an enzymic quantification of phosphatidylglycerol in amniotic fluid. Phosphatidylglycerol is hydrolyzed in alkali and the resulting glycerol is then enzymatically phosphorylated with adenosine 5'-[gamma-32P]triphosphate to yield glycero[32P]phosphate. After removal of excess [gamma-32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. Triglyceride in the amniotic fluid is hydrolyzed by lipase before extraction and thus does not interfere with the analysis. This method is specific for phosphatidylglycerol. Preliminary studies suggest that a phosphatidylglycerol value greater than or equal to 10 nmol/mL correlates with fetal lung maturity.

An enzymic radiochemical method for determining phosphatidylglycerol in amniotic fluid

We describe an enzymic quantification of phosphatidylglycerol in amniotic fluid. Phosphatidylglycerol is hydrolyzed in alkali and the resulting glycerol is then enzymatically phosphorylated with adenosine 5'-[gamma-32P]triphosphate to yield glycero[32P]phosphate. After removal of excess [gamma-32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. Triglyceride in the amniotic fluid is hydrolyzed by lipase before extraction and thus does not interfere with the analysis. This method is specific for phosphatidylglycerol. Preliminary studies suggest that a phosphatidylglycerol value greater than or equal to 10 nmol/mL correlates with fetal lung maturity.

New method for determining lecithin and sphingomyelin in amniotic fluid

We describe a new method of complete analysis for lecithin, lysolecithin, and sphingomyelin in amniotic fluid. The analysis is based on alkaline hydrolysis of the lecithins and the enzymic hydrolysis of sphingomyelin. The choline formed in each instance is enzymically phosphorylated with [gamma-32P]ATP to yield [gamma-32P]phosphorylcholine, which is isolated by anion-exchange chromatography and shown to be stoichiometrically related to lecithin, lysolecithin, and sphingomyelin. Other phospholipids do not interfere. Using this methodology, we developed three potential approaches to the assessment of fetal lung maturity: the ratio of lecithin plus lysolecithin (total lecithin) to sphingomyelin, the total lecithin concentration, and total lecithin as a percentage of total amniotic fluid phospholipids. All three indices were compared with the lecithin/sphingomyelin ratio obtained by a chromatographic procedure. Our data suggest that measuring the percentage of total lecithin may provide the best means of evaluating fetal lung maturity, but a final judgment must await clinical investigation.

New method for determining lecithin and sphingomyelin in amniotic fluid

We describe a new method of complete analysis for lecithin, lysolecithin, and sphingomyelin in amniotic fluid. The analysis is based on alkaline hydrolysis of the lecithins and the enzymic hydrolysis of sphingomyelin. The choline formed in each instance is enzymically phosphorylated with [gamma-32P]ATP to yield [gamma-32P]phosphorylcholine, which is isolated by anion-exchange chromatography and shown to be stoichiometrically related to lecithin, lysolecithin, and sphingomyelin. Other phospholipids do not interfere. Using this methodology, we developed three potential approaches to the assessment of fetal lung maturity: the ratio of lecithin plus lysolecithin (total lecithin) to sphingomyelin, the total lecithin concentration, and total lecithin as a percentage of total amniotic fluid phospholipids. All three indices were compared with the lecithin/sphingomyelin ratio obtained by a chromatographic procedure. Our data suggest that measuring the percentage of total lecithin may provide the best means of evaluating fetal lung maturity, but a final judgment must await clinical investigation.

How many well baby visits? A randomized trial in progress

The objective of this study in progress is to determine whether decreasing the number of well-baby visits during the first two years of life from the currently allowable ten visits to five, can be done with efficacious and safe results. Five hundred babies under the care of their family physicians were randomly assigned to an experimental group receiving five well-baby visits in the first two years of life or to a control group receiving ten visits. This article presents the results pertaining to the collection of the cohort.

Estimation of free triiodothyronine in serum: a new method and its clinical relevance

We describe a method for estimating free triiodothyronine in serum by polyacrylamide gel filtration. Precise and easy to perform, it avoids the lengthy incubation required for equilibrium dialysis. Results of this procedure correlate well with those by the dialysis method over a wide range of thyroid states. The role of free triiodothyronine as part of a protocol for the evaluation of thyroid status is discussed.

Estimation of free triiodothyronine in serum: a new method and its clinical relevance

We describe a method for estimating free triiodothyronine in serum by polyacrylamide gel filtration. Precise and easy to perform, it avoids the lengthy incubation required for equilibrium dialysis. Results of this procedure correlate well with those by the dialysis method over a wide range of thyroid states. The role of free triiodothyronine as part of a protocol for the evaluation of thyroid status is discussed.