[Erythropoiesis in myelodysplastic syndrome detected by multiparameter flow cytometry]

By staining human bone marrow cells with a monoclonal antibody reacting with surface antigens on erythroid precursor cells (AS-E1) and with propidium iodide reacting with nuclear DNA, we have evaluated the proliferative activity of erythropoiesis in patients with myelodysplastic syndromes using flow cytometric analysis. Comparing 36 patients (13 RA/RAS, 13 RAEB, 10 RAEB-t) with seven normal controls, significant differences in both the percentage of erythroid precursor cells and the fraction of these cells in the S or S-G2M-phase of the DNA cell cycle between the four groups were found. Since neither the percentage of erythroid precursor cells nor their fraction in S or S-G2M phase alone was found to characterize their proliferative activity, we calculated the proliferative fractions of the erythroid cells, i.e. the number of the erythroid precursor cells in S or S-G2M related to all bone marrow cells in S or S-G2M phase. Applying these parameters, we found significantly increased proliferative fractions of erythroid precursor cells in the RA/RAS patients compared to the normal controls (p-0.03 and 0.002 respectively), as well as a highly significant decrease with disease progression.

Evaluation of transfusional iron overload before and during iron chelation by magnetic resonance imaging of the liver and determination of serum ferritin in adult non-thalassaemic patients

The ability to quantitate transfusional iron overload is crucial for determining the need for and the efficacy of chelation therapy in patients with long-standing transfusion-dependent anaemias. We evaluated the usefulness of some indirect measures of iron overload in estimating the iron concentration in the liver--the most important iron storage organ--in 26 non-chelated adult non-thalassaemic patients. Liver iron concentration was determined non-invasively by magnetic resonance imaging (MRI). The standard error of the estimated liver iron concentration was 80 mumol Fe/g dried liver tissue when using the number of transfused blood units, and 93 mumol Fe/g when using a serum ferritin assay. Follow-up in 11 patients (12-48 months) revealed that serum ferritin is a poor measure of the liver iron concentration during iron chelation. However, this discrepancy was individually different and seemed to be dependent on the erythropoietic marrow activity. By monitoring the liver iron concentration by MRI, we compared the efficacy of chelation with desferrioxamine given either by subcutaneous continuous infusions or by bolus injections. Depletion of liver iron stores could be achieved efficiently by both regimens.

Translocation (1;16) identified by chromosome painting, and PRimed IN Situ-labeling (PRINS). Report of two cases and review of the cytogenetic literature

We used the molecular cytogenetic in situ techniques chromosome painting and PRimed IN Situ labeling (PRINS) to elaborate the cytogenetic observations in two cases of the rare aberration der(16)t(1;16), which occurs in a wide variation of hematologic and nonhematologic malignancies [1-3]. Review of the literature showed that, in contrast to the chromosome 1 breakpoint, the breakpoint on chromosome 16 is associated with diagnosis as well as patient age.

The pension fund for nurses in Denmark

As women and because of their job mobility and low wages, female nurses in many countries are among the employee groups most severely disadvantaged under pension schemes. For many national nurses' associations, an adequate and equitable pension income for nurses after retirement is a major concern. Below a report on the system the Danish Nurses' Organization secured for nurses in Denmark--a system that offers nurses the best possible pension conditions and support when ill and disabled--and on page 177 a summary of efforts by the American Nurses' Association to make a portable pension system for nurses a legal requirement for employers.

The effect of iron overload and iron reductive treatment on the serum concentration of carbohydrate-deficient transferrin

The concentration of carbohydrate-deficient transferrin in serum (CDT) has been used as a reliable indicator of recent alcohol consumption. We have investigated the utility of this laboratory test in 20 patients with hereditary haemochromatosis (HH) by simultaneous evaluation of serum concentrations of liver transaminases, gamma-glutamyl transpeptidase, iron, transferrin and assessment of the liver iron concentration by magnetic resonance imaging. 11 patients were re-examined during iron depletion with phlebotomies. In all 11 patients intensive but not maintenance iron removal was associated with an increase in serum CDT, in three patients even to levels above the reference range. The mean serum CDT increased from 8.5 (SD 2.2) U/l to 16.6 (SD 7.2) U/l (P < 0.001). Iron mobilization from the liver was found particularly responsible for the increase in serum CDT. Independent of this finding we found a significant semi-logarithmic correlation (r = -0.77, P = 0.009) between the MRI determined liver iron concentration and serum CDT in the patients not on iron depletion. Our findings indicate that the utility of serum CDT as a measure of alcohol consumption in patients with HH may be compromised, especially during intensive iron depletion.

Population pharmacokinetics of vancomycin in neonates

OBJECTIVE

To determine population pharmacokinetic parameters of vancomycin in neonates.

METHODS

This was a retrospective design, with prospective validation. Two hundred ten sequential neonates were evaluated at the neonatal intensive care units of Minneapolis Children's Medical Center and Children's Hospital of St. Paul. Five hundred twenty serum concentrations from 192 patients were included. A mean +/- SD gestational age of 29.5 +/- 5.1 weeks, postnatal age of 16.5 +/- 19.6 days, and dosing weight of 1492 +/- 1053 gm described the population. Thirty additional patients were studied for validation. Dosing, serum concentrations, and 28 covariates were collected. Data were evaluated with NONMEM. Forward selection and backward elimination regression identified significant covariates. One- and two-compartment population pharmacokinetic parameters and predictive performance of the models were measured.

RESULTS

Two-compartment final regression equations were as follows: Clearance (CL) = 0.0590 L/kg/hr (multiplied by 0.460 if exposed to dopamine and 0.643 if gestational age was < or = 32 weeks), central volume (VC) = 0.440 L/kg, intercompartmental clearance (Q) = 0.0313 L/hr/kg, and steady-state volume of distribution (Vss) = 0.764 L/kg. Interindividual variability was 40.6% for CL, 54.1% for Vss, and 16.8% for VC. Residual variability was 3.3 micrograms/ml. One-compartment final regression equations were: CL = 0.0626 L/kg/hr (multiplied by 0.455 if exposed to dopamine and 0.656 if gestational age was < or = 32 weeks), and Vd = 0.496 L/kg. Differences in relative performance were insignificant by use of one- or two-compartment parameters.

CONCLUSIONS

Gestational age < or = 32 weeks and concurrent use of dopamine were significant factors in prediction of vancomycin clearance. alpha Half-lives of 2.8 to 3.7 hours and beta half-lives of 13.4 to 33.7 hours suggest that some individuals in this neonatal population have considerably longer half-lives than those previously reported.

Non-invasive assessment of tissue iron overload in the liver by magnetic resonance imaging

We investigated the clinical usefulness of a standard magnetic resonance imaging (MRI) system for non-invasive determination of the liver iron concentration in 38 patients with iron overload and 15 normal controls by measurement of the signal intensity ratio between liver and skeletal muscle (SIR). However, SIR was found dependent on the applied repetition time (TR) of the MRI system, which led us to investigate this relationship in autopsy material of liver and muscle tissue specimens with various iron content. Based on these results, adjustment of SIR measurements to a constant value of TR was achieved. By use of this technique we found a close correlation between MRI and chemically determined liver iron concentration (r2 = 0.98) as well as the serum ferritin concentration (r2 = 0.86). The reproducibility was sufficiently good for the use of MRI in the follow-up of iron reductive treatment. The use of iron store parameters in serum was found insufficient as indicators of endpoint for venesection therapy, if 20 mumol Fe/g dry weight was applied as the upper reference limit of the liver iron concentration. It is concluded that MRI based on SIR measurements offers a precise and reproducible non-invasive method for the determination and follow-up of iron overload within a wide range of liver iron concentrations. Our findings may increase the clinical use of MRI in haematological patients with iron overload.

Heart transplantation in a case of juvenile hereditary haemochromatosis followed up by MRI and endomyocardial biopsies

Cardiac involvement in hereditary haemochromatosis (HH) is a poor prognostic sign and is the main cause of death in the juvenile form. The treatment of choice is iron removal therapy by phlebotomy, but treatment by iron chelation (desferrioxamine) has been recommended in cases with severe cardiac symptoms. We describe here the first case of juvenile HH undergoing heart transplantation, which became necessary despite intensive iron removal therapy by phlebotomy and treatment by desferrioxamine. Throughout the course the myocardial iron content was monitored by endomyocardial biopsies and by magnetic resonance imaging (MRI). At the last follow-up, 18 months after transplantation, the myocardial iron content in the transplanted heart was still within reference ranges by biochemical determination and MRI and the patient's condition was completely satisfactory. In conclusion, heart transplantation should be considered in cases of severe juvenile HH. In the follow-up of these patients MRI may be a useful supplement.

[Developments in the Scandinavian countries' nurses' salaries and employment conditions in the 80s]

This article is based on a report published by the Northern Nurses' Federation (NNF) as background material for a conference on Nordic Nurses' Remuneration and Employment Conditions 22-24 October 1991, Denmark. The report contains an overview and analysis of data on nurses' remuneration and employment conditions obtained from the five Nordic nurses' associations: the Swedish Federation of Health Officers, the Danish Nurses' Organization, the Norwegian Nurses' Association, the Finnish Federation of Nurses and the Islandic Nurses' Association comprising the NNF. To make the report accessible for international use, English summaries have been added at the end of each chapter, and the headings of tables and figures are translated into English.

[Extramedullary manifestations among adult patients with acute lymphoblastic leukemia (ALL)]

In 56 adult acute lymphoblastic leukemia (ALL) patients, 71% presented with extramedullary leukemic infiltration in lymphoid tissues (EML- spleen, liver, lymphnodes or thymus). EML was seen most often in patients with T-ALL (0.05 greater than p greater than 0.02) and in patients with high white blood counts (0.1 greater than p greater than 0.05). Surprisingly, these more often achieved complete remissions (0.1 greater than p greater than 0.05), of which both the duration and disease-free survival were longer. Thus, EML at diagnosis seems to be a favourable prognostic factor. At diagnosis, 23% of the patients had extramedullary leukemic infiltration in non-lymphoid tissue (EMIL-CNS, testis, skin, pleural cavities or gingiva). While more of these patients were of T-cell origin (61%, p less than 0.01), they were less likely to achieve CR, both the duration of remissions (p less than 0.01) as well as the disease free survival were shorter. Not unexpectedly, during the course of disease, the incidence of relapse localised at EMIL (the majority presenting in "sanctuary sites") increased, while that in the bone marrow decreased. Interestingly, in patients in CR presenting with EMIL, the first sign of relapse was unilateral peripheral facial paralysis in 60%. Finally, it should be stressed that the course of disease in patients presenting with simultaneous EML- and EMIL involvement was like that seen for EMIL patients. We conclude that while involvement of leukemia in EMIL represents a bad prognostic sign, the affection of leukemia in EML does not seem to confer a poorer prognosis, for adult ALL patients.

The unusual stability of the IS10 anti-sense RNA is critical for its function and is determined by the structure of its stem-domain

IS10 transposition is regulated by an approximately 70 nt anti-sense RNA, RNA-OUT. RNA-OUT folds into a duplex 'stem-domain' topped by a loosely paired 'loop-domain'. The loop-domain is critical for RNA-RNA pairing per se; pairing initiates by interaction of the RNA-OUT loop with the 5' end of the target mRNA. We show here that RNA-OUT is unusually stable in vivo (half-life 60 min) and that this stability is conferred by specific features of the RNA-OUT stem-domain. One critical feature is stable base-pairing: mutations that disrupt stem pairing destabilize RNA-OUT in vivo and abolish anti-sense control; combinations of mutations that restore pairing also restore both stability and control. We propose that the stem renders RNA-OUT resistant to 3' exoribonucleases. Other features of the stem-domain prevent this essential duplex from being an effective substrate for double-strand nucleases: two single base mutations disrupt antisense control by making RNA-OUT susceptible to RNase III. Mutations in the loop region have little effect on RNA-OUT stability. Implications for IS10 biology and the design of efficient anti-sense RNAs are discussed.