Long term non-invasive endothelial function assessment in patients with paediatric inflammatory multisystem syndrome temporarily associated with Covid 19 (PIMS TS)

Funding Acknowledgements

Type of funding sources: None.

Introduction

Patients with PIMS-TS present with features of vasculitis (bright coronary arteries and diffuse coronary ectasia on transthoracic echocardiography) and prothrombotic features (e.g. elevated D Dimers) indicating involvement of the endothelial layer in the inflammatory process. Impairment in endothelial function may contribute to the acute but also to possible long-term consequences in patients with PIMS-TS. The aim of this pilot study is to assess non-invasively the endothelial (dys)function using reactive hyperemic peripheral arterial tonometry (RH-PAT) 6 months after the acute inflammatory phase. 

Methods

Ten patients with previous diagnosis of PIMS-TS were compared to  age-matched controls. The endothelial function was assessed using the EndoPAT device which provides the reactive hyperemic index (RHI) of endothelial function in a 15-min test. Cardiac function indices by means of LV fractional shortening (FS) was also assessed.

Results

There were no significant differences regarding age (11.2 ± 3.0 vs 13.6 ± 2.4, p = 0.063), height, weight and body surface area, (BSA: 1.49 ± 0.36 vs 1.52 ± 0.25, p = 0.856) in patients with previous diagnosis of PIMS-TS and controls respectively. The two groups also had similar LV systolic function assessed by FS (36.3 ± 9.1% vs 36.7 ± 7.1%, p = 0.922). The RHI in the PIMS TS group was similar to the control group (1.65 ± 0.43 vs 1.81 ± 0.60, p = 0.533 respectively).

Conclusions.  Patients with PIMS-TS who may present with features of vasculitis during the acute phase, do not show evidence of endothelial dysfunction during the long term follow-up, suggesting resolution. Further studies are required to accurately determine the endothelial (dys)function during the acute phase of the inflammatory syndrome and course.

P1486 An unexpected case of paediatric heart failure

A 9-month-old male presented in heart failure with a 2-day history vomiting that followed a viral upper respiratory tract infection 10 days previously. Echocardiography demonstrated a normally connected heart with a severely dilated and poorly functioning left ventricle with bright mitral valve papillary muscles. It was difficult to demonstrate the origin of the left coronary artery and retrograde flow was seen in the vessel (Fig 1, Panel A). The right coronary artery appeared normal. A gated cardiac CT was performed and showed a normal right coronary origin and no clear connection of the LCA to Ao and there was suspicion of retrograde filling. Images of the left coronary origin did not show clear connection of the LCA to Ao (Fig 1, Panel B). As the case was extremely unusual coronary angiography was performed which confirmed the suspicion of a dominant right coronary system with collateral connection to the left coronary system and retrograde filling and no antegrade filling of the LCA from the Ao (Fig 1, Panel C). This was consistent with atresia of the left coronary ostium, which was confirmed at operation. The left coronary sinus was opened, as was the roof of the left coronary artery and an anastomosis was performed to aorta using an autologous patch. The post operative TOE showed good flow into the LCA (Fig 1, Panel D). There was good and quick post op clinical recovery but the left ventricular function remains still poor at the moment with slow recovery as expected. The cardiac function will be monitored echocardiographically and the reconstructed coronary artery with CT.

Abstract P1486 Figure 1

Improving Community Advisory Board Engagement in Precision Medicine Research to Reduce Health Disparities

Community Advisory Boards (CABs) are used in efforts to reduce health disparities; however, there is little documentation in the literature regarding their use in precision medicine research. In this case study, an academic-CAB partnership developed a questionnaire and patient educational materials for two precision smoking cessation interventions that involved use of genetic or genetically-informed information. The community-engaged research (CEnR) literature provided a framework for enhancing benefits to CAB members involved in developing research documents for use with a low-income, ethnically diverse population of smokers.The academic partners integrated three CEnR strategies: 1) in-meeting statements acknowledging their desire to learn from community partners, 2) in-meeting written feedback to and from community partners, and 3) a survey to obtain CAB member feedback post-meetings. Strategies 1 and 2 yielded modifications to pertinent study materials, as well as suggestions for improving meeting operations that were then adopted, as appropriate, by the academic partners. The survey indicated that CAB members valued the meeting procedure changes which appeared to have contributed to improvements in attendance and satisfaction with the meetings. Further operationalization of relevant partnership constructs and development of tools for measuring these aspects of community-academic partnerships is warranted to support community engagement in precision medicine research studies.

Abstract A69: Racial disparity in breast cancer hospital treatment costs: Examining the effect of depression

Objective: The effect of depression on hospital costs for breast cancer (BC) patients by race remains unknown. This presentation examines two issues by race: (i) hospitalized prevalence of BC and depression among discharged patients, and (ii) racial variation regarding the effect of depression on hospital costs of BC patients.

Methods: For BC, available 2008 Tennessee Hospital Discharge Data System (HDDS) was examined. The BC sample (n=2,522) was mostly white (86%) with an average age of 63 years. We computed age-adjusted BC rates per CDC methodology, and determined racial disparity. We compared the hospital costs for BC patients with depression (BC+D) vs. without depression (BCND).

Results: Age-adjusted BC rates (per 100K) were higher among white than black patients (43.3 vs. 9.2, p<.001). Further, 25% of BC patients were depressed (depression was higher among white than black patients [26% vs. 14%, p<.01]). Hospital costs for BC were 30% higher compared to non-BC patients. Further, the cost for depressed patients (BC+D) was 56% higher compared to nondepressed (BCND) patients ($64,439 vs. $41,344). Importantly, the higher costs for depressed patients (BC+D) were similarly higher among both black and white female patients compared to their nondepressed (BCND) peers.

Conclusion: BC prevalence rate is higher among white females compared to black females. Depression increases hospital costs for both white and black patients. Since depression increased cost for both racial groups of patients, considerable cost savings might be attained by screening and treating depression among BC patients before their hospitalization.

Citation Format: Baqar Husaini, Oscar Miller, Jessica Jones, Robert Levine. Racial disparity in breast cancer hospital treatment costs: Examining the effect of depression [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A69.

Abstract 4218: Racial similarities in the effects of depression on hospital cost of breast cancer

Objective: Breast cancer (BC) incidence is reported to have declined in the nation. However, the role of depression on hospital costs for BC by race remains unknown. In this presentation, we examine two issues: (i) prevalence of BC with comorbid depression among discharged hospital patients; (ii) racial variation in the effect of co-morbid depression on hospital costs of BC patients.

Methods: We extracted data on depression and breast cancer from the 2008 Tennessee Hospital Discharge Data System (HDDS). The BC sample (n=2,523) patients were mostly white (86%) with an average age of 63 years. We computed age-adjusted BC prevalence rates per CDC methodology, and compared the hospital costs for BC patients with vs. without depression.

Results: Age adjusted BC rates (per 100,000) were higher among white than black patients (92.2 vs. 43.3, p<.000). Nearly one-fourth (23%) of BC patients had depression (no racial differences: (25% white vs. 24% black BC patients). Hospital costs for BC patients were 17% higher compared to non-BC patients, and cost was 55% higher among BC patients with co-morbid depression compared to non-depressed BC patients ($64,439 vs. $41,344). The higher cost for depressed BC patients was similar across both white and black BC females.

Conclusion: BC is higher among white females compared to black females. BC patients cost with depression tended to be significantly higher compared to non-depressed patients regardless of race. Since nearly one-fourth of BC patients were depressed with higher hospital cost, these results point to possible significant costs savings by treating depression before the need for hospitalization among BC patients.

Citation Format: Baqar A. Husaini, Oscar Miller, Meggan Novotny, Robert Levine. Racial similarities in the effects of depression on hospital cost of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4218. doi:10.1158/1538-7445.AM2017-4218

Myocardial deformation in fetuses with coarctation of the aorta: a case-control study

OBJECTIVE

To study myocardial deformation by speckle tracking echocardiography in fetuses with coarctation of the aorta (CoA) compared with gestational age-matched normal controls.

METHODS

This was a retrospective study of 12 fetuses with postnatally confirmed CoA and 12 gestational age-matched controls seen at a tertiary fetal cardiology unit between January 2013 and July 2014. Two-dimensional speckle tracking in standard grayscale four-chamber view of the fetal heart was performed to assess left and right myocardial deformation. Global longitudinal strain, strain rate and velocities, and regional longitudinal strain were analyzed and compared with controls.

RESULTS

Median gestational age at echocardiography was 25 + 4 weeks. Fetuses with CoA presented with a narrower, but not shorter, left ventricle when compared with controls (mitral valve diastolic diameter, 5.90 vs 8.50 mm; P = 0.002; left ventricular diastolic length, 16.50 vs 18.50 mm; P = 0.05). Global longitudinal systolic strain (P = 0.004), systolic strain rate (P = 0.01) and diastolic strain rate (P = 0.004) of the left ventricle were significantly lower in fetuses with CoA compared with controls. Similar findings were observed for longitudinal systolic (P = 0.03) and diastolic (P = 0.01) velocities of the left ventricle. Right ventricular parameters were not different between groups.

CONCLUSIONS

Fetuses with CoA have lower left ventricular longitudinal systolic strain, systolic strain rate and diastolic strain rate when compared with gestational age-matched control fetuses. These differences in deformation might explain, at least in part, the cardiac asymmetry observed in fetuses with CoA. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal diagnosis of left ventricular diverticulum and coarctation of the aorta

Congenital left ventricular diverticulum (LVD) is a rare abnormality of the myocardium which has been detected previously in the fetus. Lesions have been reported from as early as 12 weeks' gestation but are more commonly detected in the mid-second trimester. Fetal presentation of LVD ranges from an abnormal four-chamber view of the heart, arrhythmia or isolated pericardial effusion to fetal hydrops with associated heart failure. Here, we describe the prenatal diagnosis of an infant with LVD originating from the left ventricular outflow tract associated with coarctation of the aorta. The diagnosis was confirmed postnatally by two-dimensional echocardiography and cardiac magnetic resonance imaging. We hypothesize that the lesion compromised antegrade flow into the transverse aortic arch, which may have contributed to underdevelopment of the aortic arch and subsequently the development of coarctation of the aorta. This is a unique case of LVD and coarctation of the aorta.

Oral D-mannose in recurrent urinary tract infections in women: a pilot study

Background:

In recurrent urinary tract infections (UTIs) usual prophylactic antibiotic regimes do not change the long-term risk of recurrence. Our aim was to evaluate the efficacy of D-mannose in the treatment and prophylaxis of recurrent UTIs.

Methods:

In this randomized cross-over trial female patients were eligible for the study if they had an acute symptomatic UTI and three or more recurrent UTIs during the preceding 12 months. Suitable patients were randomly assigned to antibiotic treatment with trimethoprim/sulfamethoxazole or to a regimen of oral D-mannose 1 g 3 times a day, every 8 hours for 2 weeks, and subsequently 1 g twice a day for 22 weeks. They received the other intervention in the second phase of the study, with no further antibiotic prophylaxis. The primary endpoint was evaluation of the elapsed time to recurrence; secondary endpoints were evaluation of bladder pain (VASp) and urinary urgency (VASu).

Results:

The results for quantitative variables were expressed as mean values and SD as they were all normally distributed (Shapiro–Wilk test). In total, 60 patients aged between 22 and 54 years (mean 42 years) were included. Mean time to UTI recurrence was 52.7 days with antibiotic treatment, and 200 days with oral D-mannose ( p < 0.0001).

Conclusions:

Mean VASp, VASu score, and average numbers of 24-hour voidings decreased significantly. D-mannose appeared to be a safe and effective treatment for recurrent UTIs in adult women. A significant difference was observed in the proportion of women remaining infection free versus antibiotic treatment.

Phylogenetic analysis of spring virema of carp virus reveals distinct subgroups with common origins for recent isolates in North America and the UK

Genetic relationships between 35 spring viremia of carp virus (SVCV) genogroup Ia isolates were determined based on the nucleotide sequences of the phosphoprotein (P) gene and glycoprotein (G) genes. Phylogenetic analysis based on P gene sequences revealed 2 distinct subgroups within SVCV genogroup Ia, designated SVCV Iai and Iaii, and suggests at least 2 independent introductions of the virus into the USA in 2002. Combined P- and G-sequence data support the emergence of SVCV in Illinois, USA, and in Lake Ontario, Canada, from the initial outbreak in Wisconsin, USA, and demonstrate a close genetic link to viruses isolated during routine import checks on fish brought into the UK from Asia. The data also showed a genetic link between SVCV isolations made in Missouri and Washington, USA, in 2004 and the earlier isolation made in North Carolina, USA, in 2002. However, based on the close relationship to a 2004 UK isolate, the data suggest than the Washington isolate represents a third introduction into the US from a common source, rather than a reemergence from the 2002 isolate. There was strong phylogenetic support for an Asian origin for 9 of 16 UK viruses isolated either from imported fish, or shown to have been in direct contact with fish imported from Asia. In one case, there was 100% nucleotide identity in the G-gene with a virus isolated in China.

Factor structure, reliability, and validity of the Penn State Worry Questionnaire: differences between African-American and White-American college students

This study examined differences in the factor structure of the Penn State Worry Questionnaire (PSWQ) between African-American (n=181) and White-American (n=180) college students. Results from a confirmatory factor analysis indicated that the traditional single-factor solution did not provide the best fit for the data from either ethnic group. A multiple-group factor analysis indicated that underlying structure of Factor 1 was roughly equivalent between ethnic groups. Structure of Factor 2, however, differed between groups. Specifically, item 10 loaded on different factors for each group. In support of these analyses, an exploratory factor analyses (EFA) among White-American participants indicated the presence of a two-factor model while an EFA among African-Americans indicated the presence of three factors. Despite some overlap in the overall factor structure between ethnic groups, African-Americans scored significantly lower on the PSWQ than the White-American group. Furthermore, among African-Americans level of ethnic identity was negatively related to state and trait measures of anxiety, but unrelated to measures of depression and worry.

Urinary tract infection and pyelonephritis

UTIs are common, potentially severe infections that the emergency physician must manage efficiently and effectively. In most cases, this entity is well recognized, and the clinician will be confident of the correct course. However, in certain populations, complications are common, and the best therapy has yet to be proven. Tailoring the evaluation and treatment to the risk of complications is imperative. With careful evaluation, individualized therapy and close follow-up, the majority of patients can be expected to do well.

Residual pulmonary hypertension in children after treatment with inhaled nitric oxide: a follow-up study regarding cardiopulmonary and neurological symptoms

Inhaled nitric oxide is a potent vasodilator in acute severe pulmonary hypertension and is increasingly used as rescue treatment in intensive care algorithms aiming at reducing severe hypoxaemia in neonates and children. Although the immediate effects may seem impressive, long-term outcome regarding residual pulmonary hypertension and other sequelae has been studied in only a very few patients. The aim of the present study was to evaluate residual pulmonary hypertension, cardiopulmonary or neurological symptoms in children after treatment with inhaled nitric oxide in severely hypoxaemic and/or pulmonary hypertensive mechanically ventilated children. The study was performed in four paediatric intensive care units in university hospitals in Sweden, Norway and Australia. Patients who had received inhaled nitric oxide as part of their intensive care treatment for severe hypoxaemia and/or pulmonary hypertension, and in whom 6 mo had elapsed since treatment, were included for evaluation. Thus 36 paediatric or neonatal patients were examined for circulatory, respiratory or neurological disorders with clinical examination, echocardiography, chest X-ray and a capillary blood sample. Four patients with congenital heart disease had residual pulmonary hypertension. Nine patients were receiving bronchodilators. Sixteen patients had minor (n = 15) or moderate (n = 1) changes on a chest X-ray. One patient had a possible delay in psychomotor development.

CONCLUSIONS

In spite of the severity of their primary illness, we found that the overwhelming majority of the surviving children were asymptomatic and doing well. The few residual circulatory and respiratory symptoms could be related to the initial condition.

Does public and private religiosity have a moderating effect on depression? A bi-racial study of elders in the American South

Religious activities are shown to correlate with rates of psychological depression symptoms in a sample of 995 African American and white elderly residents of Nashville. The data, collected in face-to-face interviews, included indicators of both public and private religiosity. Levels of religiosity and perceived social support were higher among the African-American respondents than among others, and among female respondents. Separate regression analyses of the racial groupings, which appeared to have distinctive religious subcultures, generally show that perceptions of social support mediate the relationship between levels of religiosity and symptoms of depression.

Screening for sickle-cell trait in the emergency department

OBJECTIVE

To determine 1) whether young adult black patients in an emergency department (ED) are familiar with sickle-cell anemia and 2) how many of these patients know their own sickle-cell trait status.

DESIGN

Black patients in an ED were interviewed. Women aged 18 to 40 years and men aged 18 to 50 were included. Sickle-cell screening was offered to the patients.

SETTING

The ED of a large urban university hospital with an annual census of 50,000, approximately 25% of whom are black.

PATIENTS

A convenience sample of 147 black patients presenting to the ED with minor medical conditions.

INTERVENTIONS

The subjects were interviewed to determine their knowledge base regarding sickle-cell anemia and to determine how many knew their sickle-cell trait status. The subjects were tested for sickle-cell trait.

MEASUREMENTS AND MAIN RESULTS

98% of the patients had heard of sickle-cell anemia and 73% knew that it was a genetic disorder. Only 31% of the patients knew their sickle-cell status. Women were more likely than men to know their status. Approximately half of the patients who had family histories of the trait or the disease knew their own status. Two of the 47 patients (4%) tested had positive sickle-cell screen results.

CONCLUSIONS

Most black patients of childbearing age presenting to the ED have heard of sickle-cell anemia and know that it runs in families, but few know their own trait status. Until access to primary care providers is improved, ED physicians who care for patients at risk for sickle-cell trait have an obligation to ask them about prior screening and either screen them or refer them for screening.

Influenza and pneumococcal vaccination in the emergency department: is it feasible?

OBJECTIVE

To assess the numbers of high-risk adult patients presenting to the emergency department (ED) who have not been vaccinated against influenza or pneumococcal disease and whether emergency physicians are willing or able to routinely provide vaccination.

DESIGN

A survey of patients in the ED considered to be at high risk for morbidity and mortality from influenza or pneumococcal disease; an anonymous, mail-back survey of emergency physicians.

SETTING

The ED of a university-affiliated hospital with an annual census of 50,000 patient visits.

PARTICIPANTS

A convenience sample of adult patients visiting the ED for any complaint who fulfilled the American Thoracic Society and Centers for Disease Control and Prevention requirements as a high-risk patient requiring vaccination with influenza or pneumococcal vaccine. The physicians surveyed were identified from the membership role of the state chapter of the American College of Emergency Physicians.

MEASUREMENTS

1) Influenza and pneumococcal vaccination rates for high-risk patients presenting to an ED during influenza season; 2) reasons for lack of immunization; 3) patient willingness to be vaccinated in the ED; 4) vaccination practice patterns for ED physicians; and 5) reasons why ED physicians are unwilling to give these vaccines.

RESULTS

212 high-risk patients were surveyed. 57% and 75% of these patients reported not having received the influenza vaccine and the pneumococcal vaccine, respectively. The main reasons for not being immunized included not being informed they needed it, a prior adverse reaction, and procrastination. Of the unvaccinated patients, 54% were willing to be vaccinated in the ED. Of the surveyed ED physicians, 89% and 93% never or rarely gave influenza and pneumococcal vaccines, respectively. 51% of the ED physicians were willing to give the vaccine. Unwillingness stemmed mainly from: 1) the perception that ED physicians are not primary care providers, 2) inadequate time or personnel; and 3) concerns about adverse reactions or medicolegal liability. Only 5% of the physicians reported organized case-finding mechanisms in their EDs.

CONCLUSION

Significant numbers of high-risk patients who are unimmunized against influenza and pneumococcal pneumonia present to the ED. There is hesitancy among ED physicians about assuming the primary care task of providing such immunizations. Any attempt to institute a large-scale vaccination program in an ED setting needs to be carefully planned in a way to involve primary care providers and to decrease ED physician concerns and reluctance.

Collaborative efforts: developing clinical experiences for nursing students in public sector settings

In the present paper we described the Nurse Academic Collaboration Task Force, which was formed in 1989 by the Texas Mental Health and Mental Retardation (TXMHMR) Commissioner in order to facilitate linkages between academia and state facilities. These efforts have led to increased academic collaboration and linkage with facilities. The task force has identified areas of practice opportunities for all levels of student education programs as well as barriers to collaboration. Collaborative strategies may also lead to better nurse recruitment efforts by TXMHMR facilities. Finally, these educational experiences should prepare nurses in varied settings to provide care for individuals with mental retardation.

Erythropoietin in liver tissue extracts and in liver perfusates from hypoxic rats

An attempt to evaluate the role of the liver in extrarenal erythropoietin production was made by measuring the content of erythropoietin in homogenates and perfusates from hypoxic rat livers. Extracts from livers from nephric or anephric animals rendered both anemic and hypoxic showed no detectable erythropoietin despite the fact that both plasma and kidney extracts contained large amounts of erythropoietin. This lack of measurable erythropoietin in the liver is not caused by degradation of erythropoietin during the extraction procedure because exogenously added rat erythropoietin was recovered to the same extent from livers or kidney homogenates. More likely, however, it is caused by the fact that extrarenal erythropoietin production accounts for only one-fifth of total erythropoietin production and that the liver mass is about six times that of both kidneys. Consequently, the erythropoietin content of 1 g of liver should be about one-thirtieth of that of 1 g of kidney, an amount that is below the limit of detection of the assay. On the other hand, the 2-h in situ perfusates of livers from similarly stimulated animals contained significant amounts of secreted erythropoietin. It is concluded that the liver participates actively in extrarenal erythropoietin production in the adult rat. However, the small amount expected to be present in tissue homogenates cannot be detected with our current bioassay.

Erythropoietin production in response to anemia or hypoxia in the newborn rat

Erythropoietin production in response to hypoxic-hypoxia is markedly reduced in the newborn when compared to the adult rat. This response improves steadily with age and reaches adult values at about 4 wk. When animals of the same age are stimulated with anemic-hypoxia, considerably higher levels of erythropoietin are found. The erythropoietin level is proportional to the degree of anemia and independent of the age of the animal. Extraction of erythropoietin from tissue homogenates revealed a parallelism between the plasma and kidney erythropoietin content, while no erythropoietin could be extracted from liver tissue at any age. The lack of response to hypoxia in the newborn appears to be related to the high hemoglobin oxygen affinity during the neonatal period, which facilitates oxygen loading. Newborn rats have a very low intraerythrocytic concentration of 2-3 DPG and a marked shift to the left in the oxygen hemoglobin dissociation curve that slowly increases to adult values at 4 wk of age. The response to anemia on the other hand, appears to be normal and not affected by age or by hemoglobin oxygen affinity. These studies suggest that the newborn rat, when properly stimulated, is able to produce normal amounts of erythropoietin, most likely renal in origin.

Serum erythropoietin levels by radioimmunoassay in polycythaemia

A radioimmunoassay (RIA) method for erythropoietin (Epo) was developed and validated against the polycythaemic mouse assay. The correlation was good, with a r = 0.94. Several other criteria of specificity were also filled by the RIA, which had a lower detection limit of 5 microU/ml. The mean serum-Epo level in 6 patients with secondary polycythaemia, 50.2 +/- 26.2 microU/ml, was significantly higher than in a group of 11 normal subjects, 28.7 +/- 7.2 microU/ml (P less than 0.0002). However, the Epo level in 31 polycythaemia vera (PV) patients, M = 21.9 +/- 6.6 microU/ml, was not significantly different from normal (P = 0.006). Since previous studies with bioassay of heat-treated and concentrated plasma samples have shown a decreased serum-Epo level in PV, Epo levels were measured before and after heat treatment and concentration of samples from normals and polycythaemics. It was found that the levels of immunoreactive material increased after heat treatment and 40 times concentration in samples from normals and patients with secondary polycythaemias, but decreased in PV. We conclude that the Epo levels in serum in the low range measured by our and previous RIA:s probably are not true Epo levels but are partly due to an unspecific serum effect, that was removed by heat treatment.

Plasma erythropoietin in health and disease

Erythropoietin is a hormone produced by the kidneys and by certain extrarenal tissues and released into the circulation in response to tissue hypoxia. Its study has provided new information about oxygen transport and bone marrow stem cell function and its determination in plasma can give valuable diagnostic clues as to the etiology and pathogenesis of anemias and polycythemias. The various methods used for such measurements are discussed, and it is recommended that the in vivo bioassay in polycythemic mice be utilized until a workable radioimmune assay has been perfected. The results with the use of this in vivo bioassay to measure plasma erythropoietin in patients with uncomplicated anemia, aplastic anemia, anemia of renal disease, anemia of chronic inflammatory or neoplastic disorder polycythemia vera, and secondary polycythemia are charted and their diagnostic significance discussed.

Erythropoietin levels in uremic nephric and anephric patients

Erythropoietin titers were measured in anemic nephric and anephric patients undergoing chronic hemodialysis by utilizing a plasma concentration technique. In eight out of 11 anephric patients studied, decreased but detectable levels of erythropoietin were found, suggesting that extrarenal erythropoietin plays a role in the regulation of red cell production in anephric patients. In 14 nephric uremic patients, erythropoietin production was found to be more variable, with one group of eight patients having erythropoietin levels in the range for normal nonanemic individuals (3.9 to 15 mU/ml), and a second group of six patients with erythropoietin higher than normal (greater than 15 mU/ml). Both groups were found to be equally anemic, indicating that in the second group the bone marrow is less responsive to erythropoietin. The severity of secondary hyperparathyroidism was found to be higher in this second group, suggesting a role of PTH in the bone marrow unresponsiveness. A good correlation between biological and immunological erythropoietin activities was found in the plasma from normal subjects and uremic nephric and anephric patients.

Plasma erythropoietin in polycythemia

Erythropoietin titers of plasma cannot be used to differentiate polycythemia vera from secondary polycythemia since the limit of sensitivity of our current bioassay technics is 50 mU, considerably higher than levels found in normal subjects and in patients with polycythemia. However, erythropoietin is relatively heat stable, and since abundant plasma is available from therapeutic phlebotomies it is possible to prepare and assay highly concentrated, erythropoietin-containing extracts. In 35 normal subjects, erythropoietin levels ranged from less than 5 mU/ml (the limit of sensitivity) to 18 mU/ml with a mean of 7.8 mU/ml. In 21 patients with proved polycythemia vera, the levels were less than 5 mU/ml in all. In 41 patients with suspected secondary polycythemia or polycythemia of unknown origin, the levels ranged from less than 5 to 3,000 mU/ml. Three of the 11 patients with levels less than 5mU/ml were subsequently shown to have polycythemia vera. These results suggest that this refinement of the routine bioassay for erythropoietin may be of clinical importance in the differential diagnosis of polycythemia.

The 5' leads to 3' polarity of the Xenopus Ribosomal RNA precursor molecule

Evidence is presented that in Xenopus laevis the 18S rRNA sequence is proximal to the 5' end of the rRNA precursor molecule and the 28S secquence is proximal to the 3' end. This assignment was made by digesting amplified ribosomal gene transcription complexes with EcoRI restriction endonuclease and spreading the cleaved transcription complexes for electron microscopy. From the known location of the EcoRI cutting sites within the transcribed region and the length of nascent chains on the cleaved transcription complexes, it was possible to make an unambiguous assignment of polarity.