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This study concentrates on the images of the nurse and nursing seen most commonly in the media and attempts to trace the images back to their origins and to explain their continued use, despite the rapidly changing role of the nurse in today's world. The images have been derived mostly from the historical roots of nursing and sometimes as a reaction to the increasing influence of the feminist movement. The author takes a look at the four main images of the nurse seen in the media, which are the ministering angel, the battleaxe, the naughty nurse and the doctor's handmaiden and then goes on to take a brief look at the other images commonly perpetuated by the media. The author summarizes the probable effects of the media stereotypes on nurses themselves and the service they provide and also takes a look at attempts to dispel these stereotypes. [ABSTRACT FROM AUTHOR]

Objectives: Validate the diagnostic accuracy of the Artificial Intelligence Large Language Model ChatGPT4 by comparing diagnosis lists produced by ChatGPT4 to Isabel Pro., Methods: This study used 201 cases, comparing ChatGPT4 to Isabel Pro. Systems inputs were identical. Mean Reciprocal Rank (MRR) compares the correct diagnosis's rank between systems. Isabel Pro ranks by the frequency with which the symptoms appear in the reference dataset. The mechanism ChatGPT4 uses to rank the diagnoses is unknown. A Wilcoxon Signed Rank Sum test failed to reject the null hypothesis., Results: Both systems produced comprehensive differential diagnosis lists. Isabel Pro's list appears immediately upon submission, while ChatGPT4 takes several minutes. Isabel Pro produced 175 (87.1 %) correct diagnoses and ChatGPT4 165 (82.1 %). The MRR for ChatGPT4 was 0.428 (rank 2.31), and Isabel Pro was 0.389 (rank 2.57), an average rank of three for each. ChatGPT4 outperformed on Recall at Rank 1, 5, and 10, with Isabel Pro outperforming at 20, 30, and 40. The Wilcoxon Signed Rank Sum Test confirmed that the sample size was inadequate to conclude that the systems are equivalent. ChatGPT4 fabricated citations and DOIs, producing 145 correct references (87.9 %) but only 52 correct DOIs (31.5 %)., Conclusions: This study validates the promise of Clinical Diagnostic Decision Support Systems, including the Large Language Model form of artificial intelligence (AI). Until the issue of hallucination of references and, perhaps diagnoses, is resolved in favor of absolute accuracy, clinicians will make cautious use of Large Language Model systems in diagnosis, if at all., (© 2024 the author(s), published by De Gruyter, Berlin/Boston.)

Objective: Pediatric rheumatology faces a looming supply-demand crisis. While strategies have been proposed to address the supply shortfall, investigation into the increased demand for pediatric rheumatic care has been limited. Herein, we analyze new patient visits to a large tertiary care pediatric rheumatology center to identify emerging trends in referrals and areas for potential intervention to meet this increased demand., Methods: All patients referred to and seen by the University of Alabama at Birmingham Pediatric Rheumatology Division between January 2019 and December 2021 for a new patient evaluation were identified. Patient data was retrospectively abstracted, de-identified, and analyzed to develop trends in referrals and frequency of rheumatic disease, non-rheumatic disease, and specific diagnoses., Results: During the study period, 2638 patients were referred to and seen in by the pediatric rheumatology division. Six hundred and ten patients (23.1%) were diagnosed with rheumatic disease. The most common rheumatic disease was juvenile idiopathic arthritis (JIA) at 45.6%, followed by primary Raynaud phenomenon (7.4%), recurrent fever syndromes (6.9%), vasculitides (6.7%), and inflammatory eye disease (6.2%). Of the 2028 patients (76.9%) diagnosed with a non-rheumatic condition, benign musculoskeletal pain was the most common (61.8%), followed by a combination of somatic conditions (11.6%), and non-inflammatory rash (7.7%)., Conclusion: In this analysis of new patient referrals to a large pediatric rheumatology center, the majority of patients were diagnosed with a non-rheumatic condition. As a worsening supply-demand gap threatens the field of pediatric rheumatology, increased emphasis should be placed on reducing non-rheumatic disease referrals., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease affecting the joints and other organs that occurs in 1 in 1,000 children in the United States. Given the various categories of JIA, interpretation of the literature can be difficult. In this review, new developments in understanding non-systemic JIA and its treatment will be covered. Recent advances in the journey toward personalized treatment in JIA will be highlighted, including a review of currently available biologic modifiers. Uveitis and the temporomandibular joint will be discussed as particularly challenging treatment issues. Recent guideline updates and literature-guided treatment decisions will be reviewed., Competing Interests: The authors declare that they have no competing interests.No competing interests were disclosed.No competing interests were disclosed., (Copyright: © 2021 Cron RQ et al.)

Juvenile spondyloarthritis is a subset of juvenile idiopathic arthritis (JIA) with onset in late childhood and adolescence and a strong association with human leukocyte antigen (HLA) B-27 positivity and familial aggregation that has the potential for axial involvement, potentially leading to ankylosing spondylitis. Current therapy for severe disease relies heavily on tumor necrosis factor inhibitors (TNFi). Treatment paradigms in children largely consist of extrapolation from studies on adults with spondyloarthritis. Additional therapies studied in adults include non-steroidal anti-inflammatory drugs (NSAIDs), blockade of the interleukin-17 (IL-17) and IL-23 axes, blockade of T-cell stimulation, phosphodiesterase (PDE)-4 inhibition, and Janus-activated kinase (JAK) pathway alteration. IL-17 blockade and IL-23 blockade are guideline approved after TNFi failure (and even as an alternative to TNFi) in adults, depending on concomitant inflammatory bowel and skin disease, with JAK and PDE-4 inhibition options following biologic failure. Neither pediatric nor adult guidelines address IL-6 blockade, T-cell co-stimulation blockade, or combination biologic therapy.

This is a good quality study that demonstrates a dramatic decrease in the incidence of contrast nephropathy with the use of sodium bicarbonate infusion prior to contrast administration. However, this study does have some shortcomings. The small sample size resulted in relatively wide confidence intervals and made the generally low attrition rate more significant. The data was not analyzed on an intention-to-treat basis, which could lead to an overestimation of the benefits of bicarbonate. None of the patients developing contrast nephropathy went on to require dialysis. The authors note that the length of hospital stay was adversely affected by the development of contrast nephropathy, although they do not report the extent to which this occurred and whether or not the increase in hospital days was significant. This study did not include the use of N-acetylcysteine, which has been shown to decrease the risk of contrast-induced nephropathy in some studies.

Two experiments compared the potency of continuous infusions of cholecystokinin octapeptide (CCK-8) for reducing sucrose intake when administered into abdominal arteries or the jugular vein. Adult, male Sprague-Dawley rats received 22-min infusions of saline or several doses of CCK-8. Sucrose was available for 20 min, beginning 2 min after onset of infusions. In the first experiment, intraceliac CCK-8 in doses of 50, 125, and 312 ng produced significant reductions in intake, but no dose affected intake when administered into the jugular vein. In experiment 2, only the highest dose, 312 ng, suppressed intake when infused into the superior mesenteric artery, and jugular infusions were again ineffective. Behavioral observations indicated that intra-arterial CCK-8 had no affect on feeding within the first several minutes of test meals but accelerated the subsequent decline in incidence of feeding. These results suggest that receptors involved in cholecystokinin satiety are widely distributed within the gastrointestinal tract.

The irradiancesof 37 spectral lines emitted bymercury pencil-type lamps were measuredby comparison with calibrated continuum sources. The lines span the region 230-590 nm. For the 14 most prominent lines the absolute irradiances should be useful for radiometric calibrations at an uncertainty level of ~15% 195% confidence2. The ratios of the irradiances for this same group of lines are significantly more reproducible; they should be useful at an uncertainty level of ~10%.

The tertiary structure of erythropoietin (EPO) remains to be elucidated by X-ray crystallography. Although the amino acid sequence of EPO is known, the specific features that confer its biological activity are not well understood. In order to study the structure-function relationships of EPO by in vitro mutagenesis, we have used the vector pGEX-2T to express human and murine EPO fused to the carboxyl terminus of glutathione S-transferase (GST) in E. coli. The fusion proteins were the predicted size (46 kDa) by SDS-PAGE. GST-huEPO eluted from glutathione-agarose using reduced glutathione (GSH) was tested by radioimmunoassay and in a mouse spleen cell assay (MSCA). Dose-response curves parallel to recombinant human EPO (rHuEPO) were obtained in both assays. The ratio of immuno- to bioactivity was 4.7:1. Thus the presence of the 26 kDa GST protein at the end terminus of EPO does not abrogate biological activity. GST-mEPO also gave dose-response curves parallel to rHuEPO in the MSCA but not in the RIA. The wild-type murine and three mutant GST-EPO fusion proteins (166 Des-Arg, Glu 159-->Val, and Arg 163-->Glu) were tested in the MSCA and assayed for GST activity. The ratio of bioactivity to enzyme activity for the Arg 163-->Glu mutant was approximately one third of the value obtained for each of the other fusion proteins, indicating that arginine at 163 is functionally important for EPO activity. The availability of these human and murine gene constructs in pGEX should facilitate site-directed mutagenesis and permit detailed studies of the structure-function relationships for the two erythropoietins.

Impaired neutrophil responses contribute to the neonate's increased susceptibility to infection. Because granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) enhance granulocyte and macrophage number and function, their use in the management of neonatal sepsis may be beneficial. Little is known about the endogenous levels of G-CSF and GM-CSF. In adults, raised values for G-CSF, but not GM-CSF, have been demonstrated in patients with infection, and conflicting data has emerged regarding CSF levels in neonates. We have used an ELISA to measure maternal and cord serum G-CSF and GM-CSF at the time of delivery, with gestational age between 25 and 42 wk. In mothers, an inverse linear relationship between gestational age and GM-CSF levels (p = 0.049) was found, but no association with G-CSF levels was observed. In neonates, a quadratic association was found between GM-CSF levels and gestational age (p = 0.019), whereas G-CSF levels showed an inverse linear association (p = 0.015). In addition, an association was found between maternal and cord GM-CSF (p = 0.007) but not G-CSF levels in paired samples. The effect of gestational age on the cytokine levels could not be explained by the white cell count, the absolute neutrophil count, pregnancy-induced hypertension, or the presence of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Increasingly, families are being called to provide care to their elderly family members. Nursing has an important role to play in enabling families to assume such responsibilities. In this article, however, it is argued that nursing needs to examine its goals for nursing care and approaches to care delivery in their broader social, political, and economic context. Marxist theory is introduced and used to raise questions about taken-for-granted aspects of nursing practice and trends in health policy as they relate to family carers for the elderly. The article specifically examines assumptions about family, women, and household economies that are inherent in traditional nursing theory. It is argued that nursing needs to move its focus of action beyond work at the individual and family level to include work at system and policy levels. To do so, nursing must examine theoretical perspectives that enable such an inquiry into practice.

Hypobaric hypoxia has been used to induce tumor hypoxia for in vivo comparison of the anti-tumor effects of the bioreductive agents SR 4233 (3-amino-1,2,4-benzotriazine-1,4-dioxide), RSU 1069 (1(2-nitro-1-imidazolyl)-3-aziridino-2-propanol), and Nitromin (methylbis(2-chloroethyl)amine N-oxide). BDF mice bearing the T50/80 mammary carcinoma were treated with these agents over a range of doses under normobaric (oxic) and hypobaric (hypoxic) conditions. The time taken for the tumor to double treatment volume (volume doubling time) was used as a measure of anti-tumor effect. Volume doubling time was plotted against log dose and dose response curves were fitted. A dose enhancement ratio (the ratio of drug doses required to give an equivalent anti-tumor effect under oxic and hypoxic conditions) was determined. The dose enhancement ratios for SR 4233 and RSU 1069 were 8.8 and 8.5, respectively, showing that these agents had an equivalent and substantial enhancement of their cytotoxicity when combined with hypobaric hypoxia. For Nitromin, no significant dose response effect was obtained under oxic conditions precluding the calculation of the dose enhancement ratio. SR 4233 was found to have increased systemic toxicity when combined with hypobaric hypoxia, suggesting that it is more readily activated than the other drugs tested. This in vivo test system will allow determination of the dose enhancement ratio for novel bioreductive agents and facilitate their comparison.

Normal unstimulated lymphocytes cocultured with normal bone marrow will inhibit day-7 colony- forming units in culture. We have shown that this phenomenon has a molecular basis and attempted to characterize it further. Using specific assays and neutralizing monoclonal antibodies we have found that this granulopoietic inhibitory activity (GIA) is not due to alpha- or gamma-interferon, tumor necrosis factor, or acidic or basic isoferritins. Biochemical studies suggest that it is a glycoprotein with a molecular weight greater than 100,000 daltons. It appears to act on cells in S phase, although it may not be S-phase specific. GIA represents a novel inhibitor that merits further investigation.

The proliferative activity of B-CLL lymphocytes from 10 patients was investigated both prior to and after stimulation with TPA and PHA. The analysis of cell cycle-associated features such as BrdU incorporation and the expression of the nuclear proliferation-associated antigen, Ki-67, together with the phenotypic profile of the cells, was performed using double colour immunofluorescent methods. The unstimulated B-CLL cells represented a homogeneous population with the same cell cycle position (G0) as resting peripheral blood lymphocytes. After TPA stimulation 22.7% of the lymphocytes were found in G1, 9.4% in S + G2/M and 13.4% in post-M. PHA stimulation induced a greater proportion of cells in G1, i.e. 35% and 17.8% into S + G2/M and 13.4% into post-M. Double colour immunofluorescence was able to demonstrate that in TPA cultures the majority of the stimulated lymphocytes originated from the malignant clone. Evidence of B-CLL lymphocyte proliferation using double colour labelling with BrdU and Ig kappa and/or Ig lambda showed that a small minority of B-CLL lymphocytes were stimulated into S + G2/M phases of the cell cycle. PHA was also capable of inducing a small proportion of B-CLL cells into mitosis although this proportion of cells was smaller compared to the TPA-stimulated lymphocytes.

CA NT is a transplantable murine mammary carcinoma that causes progressive anemia accompanied by granulocytosis and splenomegaly. Serum erythropoietin (Epo) levels, as measured by RIA, did not become elevated in anemic tumor-bearing mice; there was no correlation between hematocrit and serum Epo levels. Treatment with recombinant human (rHu) Epo prevented anemia in tumor-bearing mice when given in large doses, commencing on days 3-5 of tumor growth. Recombinant human Epo-treated mice had smaller spleens than controls. When treatment commenced on day 7, the development of anemia was retarded but not completely prevented. Treatment commenced on day 14 was less effective. This study demonstrates that treatment with rHu Epo can markedly influence the course of tumor-induced anemia.

The erythropoietin gene has been cloned in three mammalian species including man and recombinant erythropoietin is now used to treat the anaemia of chronic renal failure. Despite the isolation of the gene the precise cellular location of erythropoietin synthesis remains controversial. We present studies which demonstrate erythropoietin production by kidney tubular cells. Erythropoietin gene expression (messenger RNA) was detected by in situ hybridization using an oligonucleotide gene probe and the translated protein product by immunohistochemistry employing antibodies raised to pure recombinant DNA derived erythropoietin.

The metabolism of recombinant human erythropoietin (rHuEpo) labelled with 125I has been investigated in five normal and nine 5/6-nephrectomised rabbits. The plasma erythropoietin half-life was significantly prolonged at 5.1 +/- 1.2 h (mean +/- SD) in the 5/6-nephrectomised rabbits, compared to 3.0 +/- 0.4 h in sham-operated controls (P less than 0.001). The disappearance of 125I-labelled rHuEpo is biphasic. Examination of serum by fast protein liquid chromatography (FPLC) following administration of 125I-labelled rHuEpo by FPLC showed a single peak of radioactivity in all rabbits except two of the nephrectomised group. In serum from both of these animals a second labelled peak was found, corresponding to material of MW 200,000-250,000 D. We conclude that the 5/6-nephrectomised rabbit provides a stable model for the study of hormonal metabolism in chronic renal failure.

Erythropoiesis has been examined in relation to kidney function in 38 patients during the 3-month period following successful renal transplantation, using serial determinations of erythropoietin, haemoglobin, and creatinine. Two peaks of serum erythropoietin were observed: an early peak that occurred within 2 days of transplantation and was observed in ten patients, and a late one between 8 and 30 days, observed in 28 patients. The early peak did not produce an increase in haemoglobin and occurred only in the presence of delayed onset of graft excretory function when serum creatinine was greater than 1000 mumols/l. The ineffectiveness of the early peak may be due to the uraemic environment, which is probably a sequel of the tubular damage associated with postoperative acute tubular necrosis. The late peak followed a decrease in serum creatinine to less than 200 mumols/l and was associated with an increase in haemoglobin of 3-4 g/dl during the next 2-6 weeks.

Dipeptidylaminopeptidase IV (DAP IV) cytochemical reactivity was investigated in monoclonal antibody defined T-lymphocyte subpopulations from normal blood and in cells from a series of T-cell leukemias of defined immunologic phenotype. A combined monoclonal antibody/immunocolloidal gold technic, which enabled simultaneous visualisation of immunogold label and DAP IV reactivity, was used to study enzyme reactivity in normal T-cell subpopulations. Single or several discrete granules of DAP IV reaction product were observed in 72% of OKT3+ and OKT4+ cells, whereas a significantly (P less than 0.01) lower percentage of OKT8+ cells (41%) displayed positivity; B-cells were invariably DAP IV negative. In the T-cell leukemias, DAP IV reactivity was strongest in T-lymphoblastic lymphoma and T-prolymphocytic leukemia cells. In contrast, DAP IV activity was absent or expressed in a minority of cells of the more immature T-acute lymphoblastic leukemia. The enzyme reaction also was negative in lymphocytes from other mature T-cell leukemias: T-chronic lymphocytic leukemia (OKT8+), adult T-cell lymphoma-leukemia, and Sezary syndrome (both OKT4+). DAP IV expression did not parallel that of acid phosphatase or alpha-naphthyl acetate esterase in leukemic T-lymphoid cells except in T-lymphoblastic lymphoma and T-prolymphocytic leukemia, where a strong reaction with the three hydrolytic enzymes was observed.

Co-culture in agar of normal bone marrow cells from different individuals gave granulocyte macrophage colony counts that were expected from counts made when the marrows were cultured separately. Co-culture of normal marrow with normal peripheral blood leucocytes (which did not themselves give rise to colonies) caused inhibition of colony growth only when the ratio of peripheral blood to bone marrow cells was of the order of 4 : 1. Peripheral blood or bone marrow cells from 7 of 9 patients with acute myelomonocytic leukaemia, which did not give rise to colonies, caused a marked reduction in the number of colonies obtained from normal marrow cells when cultured with them. This inhibitory effect of leukaemic cells was found when ratios of leukaemic to normal cells were as low as 1 : 4. Additional evidence that the inhibition of normal colony formation was related to the leukaemic process was obtained from follow-up studies on one of the patients whose cells lost the capacity to inhibit normal colony formation during remission and became inhibitory again on relapse.

Patients with acute lymphatic leukaemia (ALL) could be divided into two groups at diagnosis--those whose peripheral blood and/or bone marrow exhibited in vitro colony formation and those in whom it did not, but this finding did not appear to correlate with any clinical or haematological parameter, or with prognosis. The colonly-forming potential of patients with ALL in their first full remission, early relapse or second remission did not deviate significantly from previously established normal values, but the colony-forming potential of patients in early remission was very significantly reduced. No loss of colony-forming potential of normal marrow cells was noted when they were cultured with cells from patients with ALL.

Using monoclonal antibody and fresh rabbit serum, mononuclear cells from 11 healthy individuals were depleted of either helper or suppressor T-lymphocytes by complement-mediated lysis. The effect on T-lymphocyte colony formation was studied to determine the nature of the T-colony-forming cell. While depletion of either subset of T-lymphocytes significantly reduced T-colony formation compared to controls (P less than 0.01), colony formation did not differ significantly between helper or suppressor T-cell-depleted cells. Thus T-colony formation appears to be a property of both helper and suppressor T-lymphocytes, and both subsets are necessary for optimal colony formation.

Pharmacokinetic studies in ten patients with haematological disorders were undertaken on the first and second days of one course of chemotherapy. Patients received chlorambucil under fasting and non-fasting conditions. Plasma concentrations of chlorambucil were determined by a reversed-phase high-performance liquid chromatography assay. Statistical analysis by the Wilcoxon signed rank test for non-parametric data indicated that food caused a significant reduction in peak plasma levels (P less than 0.01), elimination rate constants (P less than 0.01) and area under the plasma chlorambucil/time curve (P = 0.01). Food was also found to prolong the time taken to attain peak plasma levels (P less than 0.01). Regression analysis of renal function with elimination rate constants showed that chlorambucil elimination was independent of renal function (n = 8; r = -0.007; P = 0.72). In view of these results we suggest that chlorambucil is given on an empty stomach.

Neurotoxicity in vincristine treatment has generally been considered a consequence of the cumulative dose of the drug, and liver dysfunction had been recognised as an indication to reduce the dosage. We demonstrate that neurotoxicity is also related to individual doses and that even when there is no other evidence of liver dysfunction, a raised level of serum alkaline phosphatase may predict severe neurotoxicity. Exposure to vincristine following IV injection of the drug was studied in 27 subjects by measuring the area under the vincristine plasma concentration time curve (AUC 0-infinity). A statistically significant relationship was found between the AUC0-infinity and the degree of neurotoxicity. The AUC0-infinity was related both to dose and to elevation of serum alkaline phosphatase, suggesting that elimination of the drug is impaired when serum alkaline phosphatase is raised. Among patients with elevated serum alkaline phosphatase, a small reduction in the dose of the drug resulted in lower vincristine plasma AUC0-infinity and less neurotoxicity.

The spectral irradiance of laser-produced plasmas of gadolinium and ytterbium have been determined in the 115-220-nm range for an incident 2.2-J, 30-nsec ruby-laser pulse. The effects of target geometry arnd variation of laser energy on the spectral irradiance were also studied. The potential of the source as a radiometric standard is discussed.

The hereditary deficiency of erythrocyte pyrimidine 5' nucleotidase has been investigated using an HPLC anion-exchange procedure designed to measure both red cell nucleotide content and enzymic activity. Red cell nucleotide profiles were determined using a low pH phosphate buffer salt-gradient system in 20 min, whereas a low pH buffer alone permitted the determination of enzymic activity with each of six different nucleotide substrates in less than 4 min. Both the red cell nucleotide profiles and the enzymic activity of haemolysates from two affected brothers and their children agreed well with previously published values. This unified approach should prove useful for detailed studies of deficiencies involving isoenzymes of pyrimidine nucleotidase.

Three variants of pyruvate kinase are described which have marked reduction of activity associated with severe non-spherocytic haemolytic anaemia. Each variant shows a reduced K0.5 PEP (the value of the intercept of the abscissa on the Hill plot) and reduced Hill coefficient; FDP activation and ATP inhibition are less than normal and utilization of GDP is increased. The variants are slightly less inhibited by 2,3DPG than controls but require more FDP to relieve this inhibition. Cases 1 and 2 have decreased thermostability but case 3 is normal. The mutant enzymes are further distinguished by their affinity for FDP. Their kinetic and physicochemical properties are compared with other known cases with high affinity for PEP and discussed in terms of a R in equilibrium to T model model for allosteric enzymes.

The number of granulocyte/macrophage colonies grown in vitro from bone marrow cells obtained from 90 rib segments and 30 ;normal' bone marrow aspirates was found to be highly variable. Considerable variation was also noted in the relationship between colony number and the number of cells cultured in both groups. The aspirate group was found to have a significantly greater ability to form colonies without the addition of colony-stimulating factor to the culture medium at low cell concentrations.

Segments of human umbilical cord have been used to prepare a highly active conditioned medium (HUCCM) for in vitro human granulopoiesis and have been compared with human placenta conditioned medium (HPCM) and feeder layers. The HUCCM produced more colonies on day 7 than HPCM (P less than 0.001), and colonies consisted almost exclusively (over 98%) of granulocytic cells by both morphological and cytochemical analysis. The HUCCM-stimulated colonies have a short culture life, the number of colonies being maximal on day 7 of culture with few colonies remaining on day 10. The main source of the colony-stimulating activity in the umbilical cord was found in the Wharton's Jelly component.

A miniature argon arc has been designed and tested as a new transfer standard of spectral radiance for the wavelength range from 114 nm to 330 nm. Calibration has been performed using two primary standard sources: the hydrogen arc from 130 nm to 330 nm and the blackbody line radiator from 114 nm to 130 nm. The mini-arc provides an intense, stable, and reproducible uv continuum with dc power requirements of less than 1.5 kW. The arc characteristics have been investigated, and the sensitivity of the radiant power output to various operating parameters has been measured. The rms uncertainty in the spectral radiance is estimated to be 5.3% above 140 nm and 10.1% between 114 nm and 140 nm, due primarily to uncertainties in the primary standard sources.