Correlation of plasma erythropoiesis stimulating factor(s) and immunoreactive erythropoietin levels during rapid growth in the mouse

During the early neonatal period of rapid growth in the mouse, increased plasma levels of erythropoiesis stimulating factor(s) (ESF) have been found when measured by an in-vitro bioassay technique. It is unclear whether these increased ESF levels represent increased levels of circulating erythropoietin (Ep) alone or Ep in combination with other less-defined erythropoietic stimulatory factors. To examine this issue, plasma from neonatal mice of varying post-natal ages and from normoxic and hypoxic adult mice was studied. We found that plasma Ep levels measured by radioimmunoassay (RIA) correlated significantly with in-vitro bioassayed ESF levels (r = 0.84, P less than 0.0001, n = 21). Although an in-vivo bioassay for plasma Ep proved too insensitive for rigorous correlation with data from the RIA and in-vitro bioassay, the in-vivo data were in qualitative agreement with the other two, more sensitive, assays. In all three assays the highest plasma levels were observed in the 20-day-old mice and in adult mice which had been subjected to hypobaric hypoxia for 8 h. Based on the strong agreement of the results obtained with the RIA and the in-vitro bioassay in both neonatal and adult mouse plasma, we conclude that the high plasma ESF levels of 20-day-old mice measured with the in-vitro bioassay are largely immunochemically identifiable Ep. However, the data also suggest the presence of non-Ep factors in neonatal plasma which stimulate the in-vitro bioassay.

Plasma endotoxin as a predictor of multiple organ failure and death in systemic meningococcal disease

We studied prospectively the quantitative relation of circulating endotoxin (lipooligosaccharides [LOSs]) and the development of multiple organ failure and death in 45 consecutively admitted patients with bacteriologically verified systemic meningococcal disease (SMD). A plasma LOS level of greater than 700 ng/L correlated with development of severe septic shock (P less than .0001), adult respiratory distress syndrome (P = .0035), a pathologically elevated serum creatinine level (P less than .0001), or death as a consequence of multiple organ failure (P = .0002). Initial plasma LOS levels of less than 25, 25-700, 700-10,000, and greater than 10,000 ng/L were associated with 0%, 14%, 27%, and 86% fatality, respectively. The LOS half-life after initiation of antibiotic therapy was 1-3 h. Increasing plasma LOS levels were never seen. These observations suggest that LOS quantitation using the limulus amebocyte lysate assay with a chromogenic substrate gives important progsnotic information and may provide new insight concerning pathophysiological aspects of SMD.

Immunoreactive erythropoietin and erythropoiesis stimulating factor(s) in plasma from hypertransfused neonatal and adult mice. Studies with a radioimmunoassay and a cell culture assay for erythropoietin

The objective was to study whether the high erythropoietic stimulatory activity found in plasma from neonatal mice during the growth period is erythropoietin (Ep) alone, or Ep in combination with other factors. Plasma from hypertransfused neonatal (20 d) and adult (13-20 weeks) mice were compared with a radioimmunoassay (RIA) and a cell culture assay for Ep. The RIA determines immunoreactive Ep (iEp) while the cell culture assay reflects erythropoiesis stimulating factor(s) (ESF). Compared to control values, hypertransfusion resulting in PCVs of 55% and higher reduced the mean iEp levels in neonatal and adult mice by 82% and 38%, respectively (P less than 0.01). There was no detectable difference between the mean iEp levels of hypertransfused neonatal and adult animals (P greater than 0.3). The parallel ESF data showed a reduction in mean plasma ESF levels by 68% in hypertransfused neonatal and 72% in hypertransfused adult animals (P less than 0.001). And notably, in contrast to the iEp data, the mean ESF level found in hypertransfused neonatal mice with PCVs of 55% and higher was significantly above that of hypertransfused adult animals (P less than 0.001). No correlation was found between PCV and iEp (r less than 0.4, P greater than 0.1) or ESF (r less than 0.2, P greater than 0.2) in hypertransfused animals. The parallel data from the two Ep assays show that plasma from hypertransfused 20-d-old mice contain one or more erythropoietic stimulatory factors not detected by the RIA. It is concluded that part of the high erythropoietic stimulatory activity found in plasma from neonatal mice is due to non-Ep factors.

Child neuromuscular disease in southern Norway. The prevalence and incidence of Duchenne muscular dystrophy

In a survey carried out to determine the incidence of Duchenne muscular dystrophy in South East Norway, 38 cases were ascertained among 149,975 live male births during the years 1968-1978. The overall incidence is 1:3,917 in live male births (25.33 x 10(-5). This incidence is compared with those in other studies. There is an apparent drop in incidence in the last cohort studied, and the possible role of genetic counselling and antenatal sexing are discussed.

A comparison between haematological parameters in 'capillary' and venous blood from healthy adults

In 40 healthy adult volunteers of both sexes blood samples were taken simultaneously from an antecubital vein in EDTA-Vacutainers and from a fingertip in EDTA-Microtainers. Haematological measurements were subsequently performed in an Ortho-ELT 800 WS analyzer. Significant differences were obtained between the two sets of samples. In accordance with current literature, the 'capillary' thrombocyte count was either identical to, or more frequently substantially lower than the corresponding venous count. On the contrary, the 'capillary' erythrocyte count and the haematocrit and haemoglobin values significantly exceeded those of venous blood, while the red cell indices MCV, MCH and MCHC were identical. The total leucocyte count was substantially elevated in 'capillary' blood compared with the corresponding venous samples. Moreover, the 'capillary' differential leucocyte counts showed elevations which directly reflected the various particles' size. Possible explanations of these findings are discussed.

Child neuromuscular disease in southern Norway. Prevalence, age and distribution of diagnosis with special reference to "non-Duchenne muscular dystrophy"

The prevalence of child neuromuscular disease in Southern Norway by January 1st, 1983, was studied by collecting data from all available sources. All children born 1. 1. 1965 or later were included in the study. The total group consisted of 110 patients from 17 different diagnostic categories. Total prevalence on this group was found to be 24.9 X 10(5). Duchenne muscular dystrophy (DMD), with a prevalence of 10.89 X 10(5) constituted 29.2% of the total material. In the spinal muscle atrophy group (SMA), we found a significant increase in the number of boys affected, although an autosomal recessive mode of inheritance was found likely in all probands. Prevalence figures of child neuromuscular disease are hard to compare, as most studies deal with an adult population. The prevalences of common and well-known large categories of neuromuscular diseases in childhood are in agreement with previous studies. For less well known and mild diseases, our figures are low. This may be due in part to a later onset and in part to a health system not sensitive to parents' complaints.

Fasting plasma amino acid concentrations in PKU children on two different levels of protein intake

Two groups of children with phenylketonuria were treated with different amounts of protein. One group (RDA group) received protein as recommended by the U.S. Food and Nutrition Board, the other (FAO group) the amount recommended by the FAO/WHO 1973 ad hoc Expert Committee. Two of the children in the FAO group showed a decrease in length/growth velocity which raised the question of the adequacy of the protein content in the diet. Since deviations from normal plasma amino acids have been observed in protein deficient, energy-adequate diets, we examined these parameters in the PKU children. In the two children with retardation in length/growth, very high glycine values as well as very high alanine values were observed at the end of the study. These observations strengthened our suspicion that the FAO/WHO 1973 recommendations are marginal.

Is oxygen supply the only regulator of erythropoietin levels? Serum immunoreactive erythropoietin during the first 4 months of life in term infants with different levels of arterial oxygenation

Serum immunoreactive erythropoietin (siEp) levels were measured in 35 full-term infants aged 0-13 weeks, 31 of whom had congenital heart disease. The infants displayed a wide range in arterial oxygen tension (PaO2) and oxygen saturation (SaO2). During the first days of life siEp varied widely with a range from less than 3 to more than 10,000 mIU/ml. The wide variation is consistent with findings in cord blood at term. The siEp levels did not correlate significantly with haemoglobin, haematocrit, PaO2, SaO2, or arterial oxygen content in the total sample, nor when the cohort was split up into different age groups. Cyanotic infants aged 2-13 weeks had significantly higher siEp concentrations than normal adults (p less than 0.001) and than children with cyanotic congenital heart disease, aged 4 months-10 years (p less than 0.001). The raised siEp levels in cyanotic children aged 2-13 weeks found in this study and the normal levels found in their older counterparts (4 months-10 years) (reported elsewhere) are consistent with the pattern observed in man and animals exposed to prolonged hypobaric hypoxia, in which after an initial rise in erythropoietin concentrations the levels fall to normal while increased erythropoiesis is sustained.

Erythropoietic factors in plasma from neonatal mice. In vivo studies by the exhypoxic polycythaemic mice assay for erythropoietin

The erythropoiesis stimulating factor(s) (ESF) in plasma from 20-day-old WLO-mice have previously been studied by a cell culture assay, and also by means of gel filtration chromatography and affinity chromatography. It was concluded that the high levels of ESF found in the neonatal mouse plasma probably consisted of erythropoietin (Ep) alone. The objective of the present investigation was to obtain further information of whether this high ESF found in vitro is Ep alone, or Ep in combination with other factors. To accomplish this plasma from 20-day-old WLO mice and a standard Ep were studied in vivo by the exhypoxic polycythaemic mice assay for Ep, with and without preincubation with rabbit anti-Ep serum (AS). Aliquots of some samples were also studied in vitro by the exhypoxic polycythaemic mice assay for Ep, with and without pre- in both assays (P less than 0.001). However, incubation with AS significantly reduced (P less than 0.001) but did not totally block either the in vivo or the in vitro activity of the plasma (P less than 0.005). This also was the case regarding the in vivo activity of the standard Ep (P less than 0.001), while the in vitro activity of this Ep preparation was totally blocked by incubation with AS (P greater than 0.3). These results indicate that a considerable part of the high erythropoietic stimulatory activity found in plasma from 20-day-old mice, with both assays, is Ep. This supports the previous in vitro studies. However, the present results also support the conclusion that part of the activity is due to non-Ep stimulatory factors.

Plasma erythropoiesis stimulating factor(s) in neonatal mice: in vitro dose response and chromatography studies

High levels of plasma erythropoiesis stimulating factor(s) (ESF) have been found in neonatal WLO-mice during rapid growth. A previous study on hypertransfused neonatal animals indicated that the high ESF could not be due to the concomitant postnatal anemia alone. The present investigation was performed to answer the question: Is the high plasma ESF in neonatal WLO-mice erythropoietin (Ep) alone, or Ep in combination with other factors? The ESF of plasma from 20-day-old animals and standard Ep were compared in a cell culture assay for ESF based on erythroid colony formation, and also by means of gel filtration chromatography and affinity chromatography. Nonfractionated plasma and standard Ep showed parallel dose response curves and additive activity in the ESF assay. After gel filtration the detectable ESF of plasma was eluted in the same position as that of standard Ep, corresponding to an estimated molecular weight range of 34-65,000 daltons. The ESF of intact plasma, fractionated plasma, and standard Ep were identically bound to and eluted from the affinity chromatography column. These results show that the ESF of plasma from 20-day-old animals can neither be separated into several factors, nor distinguished from that of standard Ep by the methods used. It is therefore concluded that the high plasma ESF found in neonatal WLO-mice probably consists of Ep alone.

Regulation of erythropoiesis in suckling rabbits with and without postnatal anemia: partial suppression of production/release of erythropoiesis stimulating factor(s) by iron supplements

The postnatal anemia in rabbits is accompanied by a marked rise in the plasma erythropoiesis stimulating factor(s) (ESF). The purpose of this study was to establish whether the increase in plasma ESF is only related to the anemia, or whether other mechanisms also are involved. Two matched groups of rabbits were studied from the 15th to the 36th day after birth. One group received iron parenterally and had no postnatal fall in hemoglobin concentration (Hb), the other developed the usual anemia. In both groups plasma ESF was undetectable on the 15th day, and also on the 22nd day, despite a marked fall in Hb in the untreated group and rise in the iron-treated group. Thereafter plasma ESF showed a slight, continuous rise in the nonanemic rabbits, in contrast to a marked, transient rise with maximum on the 29th day in the untreated group. On the 36th day there was no difference between the groups. In the iron-treated group the reticulocyte production rate remained unchanged, while the Hb mass rose continuously. In the untreated animals there was an initial decline in reticulocyte production rate, while Hb mass showed a slight increase. From the 29th day, however, reticulocyte production rate rose to the same level as in the iron-treated group and Hb mass rose markedly. In conclusion, the rise in plasma ESF during the postnatal anemia in rabbits is only in part related to the low Hb. Hypoxia-independent mechanisms, probably related to the growth and maturation per se also are involved. The lack of erythropoietic response to the rise in plasma ESF is due to lack of available iron.

Erythropoiesis-stimulating factor(s), erythropoiesis and erythrocyte 2,3-diphosphoglycerate in young rabbits with marked post-natal fall in haemoglobin

The erythropoietic activity and erythrocyte 2,3-diphosphoglycerate (2,3-DPG) were studied during and after the nadir of the post-natal anaemia in normal, rapidly growing rabbits, from the 12th to the 35th day after birth. Whole blood haemoglobin (Hb) decreased from 9.3 g dl-1 on the 12th to 4.9 g dl-1 on the 25th day, while erythropoiesis-stimulating factor(s) (ESF) in plasma (determined by a cell culture assay) concomitantly rose from undetectable to high levels. In spite of marked rise in body weight, from 250 to 480 g, estimated haemoglobin mass (Hb mass) and reticulocyte mass production rate (Rt prod) remained essentially the same, about 1.8 g and 0.3 ml day-1. From the 25th to the 35th day, ESF decreased to a lower level, while Hb increased to 10.8 g dl-1 and Hb mass and Rt prod rose sharply, to 6.9 and 1.2 ml day-1. The 2,3-DPG rose markedly during the observation period, but showed a transient decline on the 29th day, simultaneously with the peak in reticulocyte counts (Rt) (24%) and release of young erythrocytes with low 2,3-DPG. The data indicate that the regions governing the erythropoietin production/release became increasingly sensitive to hypoxia during the observation period. The possibility also exists that the increase in ESF was due only in part to hypoxic stimulation. It could be related to the maturation of the animal in other ways, such as shift from extra-renal to renal erythropoietin production and the growth. The lack of response to increasing stimulation indicates that the erythropoiesis was restricted by the availability of iron and/or other factors necessary for erythrocyte and haemoglobin production.

Liver transplantation in a 23-year-old tyrosinaemia patient: effects on the renal tubular dysfunction

Orthotopic liver transplantation was performed on a 23-year-old female with hereditary tyrosinaemia. The disorder was diagnosed at 7 years of age due to severe rickets, and the patient was treated with a diet restricted in phenylalanine and tyrosine. Nineteen months before the transplantation she had an acute episode of diffuse gastrointestinal bleeding due to portal hypertension. Three subsequent bleeding episodes with accompanying ascites and signs of encephalopathy were considered life-threatening. Nine months after the liver transplantation the patient is well, but serum transaminases are slightly elevated. Without dietary restrictions serum tyrosine and inorganic phosphate are normalized, no succinylacetone can be detected in serum, and urinary excretion of p-hydroxyphenyllactate and p-hydroxyphenylpyruvate is normal. Excretion of amino acids, glucose and beta 2-microglobulin decreased significantly after the transplantation but is still elevated. The succinylacetone concentration in urine is about 20% of the preoperative level. After an oral tyrosine load, succinylacetone excretion increased sevenfold but no deterioration of the renal tubular function was observed and no tyrosine metabolites were detectable in serum. The findings indicate that the defective tyrosine metabolism occurs in the kidneys, but does not produce tubular dysfunction. The residual tubular dysfunction of the patient is probably due to irreversible damage of the tubular epithelium.

Regulation of erythropoiesis during rapid growth

High levels of plasma erythropoiesis stimulating factor(s) (ESF) have been found in neonatal WLO-mice during the period of rapid growth. If the high ESF activity is due to the concomitant physiological anaemia of infancy alone, it should be possible to block erythropoiesis by hypertransfusion. Mice were hypertransfused starting on day 14, and killed on day 20. Although hypertransfusion reduced the ESF levels by approximately 55% (P less than 0.001), ESF levels were still detectable in the cell culture assay used (P less than 0.001). Moreover, hypertransfused mice showed active erythropoiesis in the bone marrow, and none had a reticulocyte count below 2%. No correlation was found between PCV and ESF in the hypertransfused animals (r = 0.07, P greater than 0.5), nor was there any difference in weight gain between control and hypertransfused mice (P greater than 0.5). These results show that hypertransfusion did not totally supress erythropoiesis in neonatal WLO-mice, which is different from hypertransfused adult mice. The data indicate that the high plasma ESF found in neonatal WLO-mice during the growth period are not due to the anaemia alone. These findings support studies indicating that regulation of erythropoiesis in the neonate differs from the adult. Factors related to growth per se could be responsible for this difference.

Net protein utilization determined by rat bioassay of a protein hydrolysate and a diet for children with phenylketonuria

In a previous study (Kindt et al. 1983, 1984) it was assumed that a protein hydrolysate, devoid of phenylalanine, together with intact protein as given to children with phenylketonuria (PKU), was equivalent to egg or milk protein. One group of children was given this 'PKU protein' in amounts corresponding to the Joint FAO/WHO ad hoc Expert Committee (1973) recommendations. The results indicated that the Joint FAO/WHO ad hoc Expert Committee (1973) recommended levels of protein intake were marginal. The purpose of the present study was to evaluate whether the quality of the protein hydrolysate, together with intact protein ('PKU protein'), is equivalent to egg or milk protein. This was done using a rat bioassay. Four protein sources were used: (1) egg protein, (2) protein hydrolysate, (3) protein hydrolysate diluted with non-essential amino acids, (4) protein hydrolysate mixed with food proteins ('PKU protein'), comparable with the diet previously used (Kindt et al. 1983, 1984). The results indicated that the 'PKU protein' was of very high quality: net protein utilization (NPU) greater than 90. The protein hydrolysate alone and the protein hydrolysate diluted with non-essential amino acids gave a NPU greater than 80. The conclusion drawn from the present study is that the 'PKU protein', as used in the treatment of children with PKU, is equivalent to egg or milk protein. This supported the view that the Joint FAO/WHO ad hoc Expert Committee (1973) recommended levels of intake were marginal.

Is phenylalanine requirement in infants and children related to protein intake?

Two groups of children with phenylketonuria (PKU) received protein at two different levels. The protein source was a protein hydrolysate, devoid of phenylalanine, and intact protein from milk, vegetables and fruit. One group (RDA group) was given protein at a level based on the recommendations of the (US) Food and Nutrition Board (1974, 1980). The other group (FAO group) was given protein at the level of intake corresponding to the Joint FAO/WHO ad hoc Expert Committee (1973) safe levels of intake of egg or milk protein. The children were monitored very closely for several years. From an earlier study evaluating the protein intake of the two groups it was suspected that the Joint FAO/WHO ad hoc Expert Committee (1973) recommendations were marginal. In the present study the phenylalanine intake of the two groups required to maintain the plasma phenylalanine concentration at the required level was established. The results showed that the RDA group required more phenylalanine than the FAO group. This difference was statistically significant from the age of 5-15 months. We have interpreted the greater requirement for phenylalanine in the RDA group as a result of a greater nitrogen intake and thus a more rapid chemical maturation of N (increase in protein concentration of the body with age). It is known that up to the age of 6 months the chemical maturation of N is related to the N intake. In the present study we have found that this difference in chemical maturation lasted up to the age of 15 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma concentrations of vitamin D metabolites before and during treatment of vitamin D deficiency rickets in children

Plasma concentrations of 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D (1,25-(OH)2D), and 24,25-dihydroxyvitamin D (24,25-(OH)2D) were determined in 17 children with vitamin D deficiency rickets before therapy was started. Thirteen of them also had these tests repeated during treatment. The median 25-OHD concentration was at the lower limit of the reference range before, but increased distinctly within one week of treatment with 1 700-4 000 IU vitamin D per day (17 vs. 37 nmol/l, p less than 0.01). 24,25-(OH)2D was undetectable in twelve of the patients before therapy. Detectable concentrations were in the range of 1.7 to 3.5% of the corresponding 25-OHD levels throughout the study, and the two metabolites were closely correlated (r = 0.84, p less than 0.0005). The median 1,25-(OH)2D concentration was near the average of the reference range before, but increased to well above the upper limit of normal within one week of treatment (121 vs. 368 pmol/l, p less than 0.01). The levels were largely normal after 10 weeks of therapy, as were the plasma concentrations of calcium, phosphate, and alkaline phosphatase. Parathyroid activity, as judged by serum parathyroid hormone or urinary cyclic AMP concentrations, was stimulated in 11 of 12 children studied prior to treatment. It is concluded that there may be no clear-cut differences between normal nad rachitic values of the different vitamin D metabolites under practical clinical conditions. A low 25-OHD level combined with evidence of a stimulated parathyroid activity, and a rise of 1,25-(OH)2D levels to supernormal values following a few days of vitamin D therapy may be diagnostic clues.

Erythrocyte 2,3-diphosphoglycerate, PO250%, and available oxygen in young rabbits with and without postnatal fall in hemoglobin

We determined erythrocyte 2,3-diphosphoglycerate (2,3-DPG), PO250%, whole blood hemoglobin concentration, and available O2 from the 12th to the 30th d after birth in two matched groups of young rabbits. One group received iron parenterally on the 12th, 15th, and 18th d and the other received no iron supplement. In the untreated group there was a marked fall in hemoglobin concentration from the 12th to the 22nd d and thereafter a marked increase to the initial level on the 30th d whereas the iron-treated animals showed a marked rise in hemoglobin concentration from the 12th to the 22nd d, and a subsequent, slight decline from the 22nd to the 30th d. The average values of PO250% and 2,3-DPG, and the changes in PO250% and 2,3-DPG were virtually identical for both groups. During the first period (12-22 d) there was a marked rise in both 2,3-DPG and PO250% whereas in the second period (22-30 d) there was a somewhat smaller rise in 2,3-DPG and only a slight tendency toward a further rise in PO250%. In the untreated animals "available O2," reflecting the O2 delivery capacity of the blood, remained unchanged during the period of fall in hemoglobin concentration and showed a rise during the second period. In the iron-treated animals "available O2" rose markedly during the first period, with iron-treatment, and remained unchanged during the second period. We conclude that the marked postnatal rise in 2,3-DPG and PO250% in the rabbit seems to be independent of the changes in the hemoglobin concentration.

Erythropoietin and uremic toxicity during continuous ambulatory peritoneal dialysis

This study examined the effect of continuous ambulatory peritoneal dialysis (CAPD) on erythropoiesis and macrophage function. The parameters evaluated were hemoglobin, erythropoiesis-stimulating factor(s) (ESF), and the inhibitory effect of patients' plasma and peritoneal dialysate on erythropoiesis in vitro and on the function of macrophages from normal humans cultured in vitro. ESF was determined by a cell culture assay using hepatic erythroid colony forming cells (CFUE) from newborn mice. The uremic inhibitory effect on macrophages cultured in vitro was expressed as macrophage survival in percentage of controls. Five patients were studied, one of whom was anephric. Hemoglobin increased, without blood transfusions during CAPD treatment, suggesting improved erythropoiesis. Plasma ESF increased in all patients; dialysate ESF increased in all but one patient. Survival of macrophage in vitro, incubated with plasma or dialysate, also improved. In two patients, the inhibitory effect of plasma samples on erythropoiesis in vitro decreased during CAPD treatment. These observations indicate that CAPD removes inhibitors of erythropoiesis and human macrophage function in vitro, and are consistent with transport of inhibitory substances of high molecular weight into the peritoneal cavity. The anephric patient showed improvement of erythropoiesis similar to that of the nephric patients, indicating that the kidney may not be the main producer of erythropoietin (Ep) in patients undergoing CAPD. Peritoneal macrophages may be a site of extrarenal Ep production in this situation. With regard to the parameters studied, CAPD treatment is superior to conventional hemodialysis.

Plasma erythropoietin concentrations during the early anemia of prematurity

Plasma erythropoietin concentrations were studied in 11 preterm appropriate for gestational age infants at the age of 3-14 weeks. Their birth weights ranged from 860-1 690 g. Erythropoietin was measured by a cell culture technique. Significant concentrations of erythropoietin was detected in 18 out of 29 samples, at all stages of the early anemia. The highest levels were found at 3-9 weeks. Individual erythropoietin values did not correlate with hemoglobin concentrations, hematocrit levels or 'corrected' reticulocyte counts, nor did the 'corrected' reticulocyte count correlate with hemoglobin or hematocrit. The lack of correlation with hemoglobin concentration most likely reflects the importance of other factors as well as the hemoglobin in determining the oxygenation status of the infant. A significant positive correlation (r = 0.60, p less than 0.01) was found between erythropoietin concentration and weight gain in the preceding week. The study shows that small preterm infants are capable of erythropoietin production during their early anemia, and indicates that the hormone plays a role in the regulation of erythropoiesis also at this time of life.

Deficient fumarylacetoacetate fumarylhydrolase activity in lymphocytes and fibroblasts from patients with hereditary tyrosinemia

Fumarylacetoacetate fumarylhydrolase (E.C.3.7.1.2.), a liver enzyme involved in tyrosine degradation, is shown to be present in many human tissues and cells including lymphocytes, fibroblasts, and cultured amniotic fluid cells. The enzyme activity in lymphocytes from six patients with hereditary tyrosinemia (hepatorenal type) and fibroblasts from three patients, was found to be less than 10% of the activity in control subjects. In lymphocytes and fibroblasts from the parents (n = 16) of the patients the enzyme values were compatible with a heterozygote genotype. The lymphocyte enzyme pattern of the control subjects (n = 97), is complicated, and indicates possible enzyme variants.

Protein requirements in infants and children: a longitudinal study of children treated for phenylketonuria

Two groups of children with phenylketonuria were followed from birth for several years. The Recommended Dietary Allowance group received a protein intake as recommended by the Food and Nutrition Board. The Food and Agricultural Organization (FAO) group received a protein intake as recommended by FAO. The children were followed very closely for the biochemical control of the disease. The children were also followed very closely to evaluate the adequacy of the protein intake using length, weight, routine hematology, chemical analysis, and x-ray of the hand. The results indicated two groups of healthy children. However, a decline in length growth percentile was found in some of the FAO children. A possible osteoporosis developed in two of the FAO children. The possible conclusion that the FAO "safe level of intakes of egg or milk protein" is marginal is discussed.

Erythrocyte 2,3-DPG, PO2 50% and available O2 during the early post-natal fall in hemoglobin in rabbits

Erythrocyte 2,3-DPG, PO2 50%, whole blood hemoglobin and available O2, and fixed acid Bohr effect were studied during the first 10 days after birth in rapidly growing suckling rabbits. The post-natal fall in hemoglobin concentration was accompanied by a marked rise in erythrocyte 2,3-DPG and a gradual increase in PO2 50%. The rise in PO2 50% was sufficient to keep the available O2 of the blood unchanged throughout the observation period. The observations show that a 2,3-DPG mediated rise in PO2 50% very effectively contributes to maintenance of adequate tissue oxygenation during the post-natal fall in hemoglobin. The rise in 2,3-DPG and and PO2 50% may be due to the ordinary hypoxia-induced shift to the right of the hemoglobin O2 dissociation curve, as observed under other circumstances when blood hemoglobin is rapidly reduced, but the very marked rise in 2,3-DPG and the very low delta PO2 50%/delta 2,3-DPG ratio suggest that the rise may as well be due to hypoxia independent, pre-programmed processes. The fixed acid Bohr effect was essentially the same in newborn and adult rabbits, and was uninfluenced by large variations in 2,3-DPG.

A study of the value of resin-embedded semi-thin sections and electron microscopy in the diagnosis of renal biopsies

Two hundred consecutive renal biopsies originally studied by light microscopy of paraffin- and semi-thin sections and electron microscopy were reviewed and re-classified according to the proposed WHO classification for glomerular disease. The accuracy of diagnoses based on paraffin sections alone, and of those based on paraffin- and semi-thin sections were compared with the results of the final evaluation, when electron microscopy also was taken into account. Paraffin material showed a diagnostic accuracy of 59 per cent for glomerulonephritis, and 82 per cent for other renal diseases. The diagnostic accuracy of semi-thin sections was 61 per cent for glomerulonephritis and 76 per cent for other renal diseases; i.e. not improved. It is concluded that the study of semi-thin sections cannot replace electron microscopy in the diagnoses of renal biopsies. In the present study, electron microscopy altered the diagnoses in 34 per cent and yielded additional useful information in another 45 per cent of patients with glomerulonephritis. Therefore, the electron microscope should be employed routinely in the study of renal biopsies from this group of patients.

A rubella epidemic in an unvaccinated pregnant population. 2. Seroepidemiology

The study is based upon primary rubella infections detected in a collection of 7,781 serum pairs from as many pregnant women out of a total number of about 12,500 in the Oslo area of Norway in 1974. In the spring of that year, a rubella outbreak occurred. The results obtained on the serum pairs were compared and supplemented with acute serodiagnostic data obtained from the files of the virus laboratories, informations obtained from the mothers when interviewed in 1976 and from the files of application for legal abortions. From October 1973 through December 1975 a total of 118 serologically confirmed pregnancy infections were detected in the area, 94 of which took place between February and July 1974. The year following the outbreak showed scattered cases, whereas the last half of 1975 was free of cases. The pairs of the collection covered about one third of the pregnancy months occurring between February 1974 through January 1975, and the rubella infections diagnosed by seroconversion during this period indicated an attack rate for the epidemic period of 2.8% pregnancy months, and 0.35% for the post-epidemic period. 50% of the infections went unrecognised when they occurred, whereas only 17% seemed to have been subclinical. It is estimated that at least 9 children may have been born with rubella sequelae following infections during this period, when the legal abortions because of rubella in taken into consideration.

Identification of low levels of heat labile enterotoxin in Escherichia coli from children with diarrhoea

Out of 40 children with gastroenteritis and massive growth of E. coli in faeces, 7 yielded growth of E. coli strains producing heat-labile enterotoxin (LT), as identified by enzyme-linked immunosorbent assay (ELISA) using anticholera toxin coated plates or ganglioside coated plates. The toxin production in vitro was low, and decreased upon subculturing for 3 months in the laboratory. Only two of the strains were identified as LT-positive by the YI adrenal cell test. In addition, an LT-producing strain was isolated from an adult who had recently returned from Jordan. Sonication of the strains after subculturing released cell-bound LT. The clinical importance of such low toxin producing E. coli strains is not known.

Influence of HLA matching in cadaveric renal transplantation: experience from one Scandiatransplant center

The outcome of 461 prospectively HLA-A, -B and -C typed and 193 prospectively HLA-DR typed cadaveric kidney transplants in one center was followed. We found a significant beneficial effect on graft survival both of HLA-A and -B as well as of HLA-DR matching between donor and recipient, while no effects of HLA-C compatibility could be detected. The effect of HLA-DR matching was clearly more pronounced than that of HLA-A and -B matching, and a possible influence of matching for HLA-A and -B could only be seen in the HLA-DR mismatched combinations. Pretransplant blood transfusions were associated with an increased graft survival only in patients receiving HLA-DR mismatched transplants. We conclude that major emphasis should be laid on obtaining HLA-DR compatibility in clinical renal transplantation.

The effect of blood transfusions on renal transplantation. Studies of 395 patients registered for transplantation with a first cadaveric kidney

Three-hundred-and-ninety-five candidates registered for a first cadaveric renal transplant have been analyzed for the effect of pre-graft blood transfusions. Of these, 348 patients were transplanted, 45 died prior to transplantation and two patients have not yet received a transplant. Slightly less than half of the transplanted patients had been transfused, and those received five or more transfusions demonstrated a superior graft survival. This was pronounced in all HLA incompatible transplants who had received five or more transfusions. In patients who received less than five transfusions, only one-two HLA antigen incompatible transplants demonstrated increased graft survival. The frequency of rejection episodes was significantly decreased in all transfused compared to non-transfused groups. Among the patients dying while waiting for a transplant, the majority had been transfused, and a significantly higher proportion of them had cytotoxic HLA antibodies, compared to those who were transplanted.

Importance of HLA-DR matching in cadaveric renal transplantation: a prospective one-center study of 170 transplants

To investigate the influence of matching for HLA-DR antigens in renal transplantation, we assessed the outcome of 170 prospectively HLA-typed cadaveric kidney transplantations performed since 1977 in one center. We found a beneficial effect on graft survival of HLA-DR compatibility between donor and recipient (P < 0.05). A possible effect of matching for the HLA-A and B antigens could be seen only in the HLA-DR-mismatched combinations. Pretransplantation blood transfusions were associated with increased graft survival only in patients receiving HLA-DR mismatched transplants (P < 0.02). We conclude that major emphasis should be placed on obtaining HLA-DR compatibility renal transplantation. (N Engl J Med. 1980; 303:850-4).

Non-antibody components in human milk inhibit Escherichia coli heat labile enterotoxin measured by an enzyme-linked immunosorbent assay

Milk from 11 Norwegian women was fractionated by ammonium sulphate precipitation and column chromatography. The milk samples inhibited the binding of heat labile E. coli enterotoxin to antibodies coated on microtiter plates in an enzyme-linked immunosorbent assay. Inhibiting activity was not detected when the toxin was measured in an adrenal cell assay. The inhibiting activity was of a non-immunoglobulin nature with an apparent molecular weight of greater than 400 000 in gel filtration experiments.

Effect of blood transfusions on renal transplantation: study of 191 consecutive first transplants from living related donors

One hundred ninety-one consecutive living related transplants performed from 1969 to the end of 1978 have been analyzed for the effect of pretransplant blood transfusions. Superior graft survival was observed in transfused patients transplanted with a one HLA haplotype-disparate kidney, whereas no effect of blood transfusions could be observed on the survival of HLA-identical transplants. The frequency of first rejection episodes was significantly reduced in transfused compared to nontransfused one haplotype-mismatched transplants, while no influence of blood transfusions was seen in patients with HLA-identical transplants. The survival of patients was, however, not influenced by previous transfusions. Pretransplant hemodialysis improved graft survival and patient survival; the difference was, however, only significant at 2 years in the one haplotype-mismatched group. When analyzed separately, both blood transfusions and hemodialysis had a beneficial effect on graft survival in one haplotype-mismatched transplants.

The need of essential amino acids in children. An evaluation based on the intake of phenylalanine, tyrosine, leucine, isoleucine, and valine in children with phenylketonuria, tyrosine amino transferase defect, and maple syrup urine disease

The diet of children with blocks in the metabolism of five amino acids has been investigated to evaluate the need for these amino acids in the maintenance of normal growth and development. Two children with phenylketonuria, one child with tyrosine aminotransferase defect and one child with maple syrup urine disease are included in the study. The growth and development of the children have been within the normal range except for language development, which was retarded in the maple syrup urine disease child. The need for phenylalanine, phenylalanine and tyrosine combined and isoleucine, leucine, and valine for protein synthesis in growing children was investigated by registering the intake of phenylalanine in the phenylketonuria children, the intake of phenylalanine and tyrosine in the tyrosine amino transferase defect child and isoleucine, leucine and valine in the maple syrup urine disease child. The significance of this intake, defined as the sufficient intake, is discussed, as well as the difference between the sufficient intake and requirement. The sufficient intake is compared with former studies on requirement. There is good agreement between the sufficient intake and requirement of phenylalanine and tyrosine. The sufficient intake of isoleucine, leucine, and valine as judged from our study is lower than in former studies on requirement.

The effect of 3-4 HLA-A and -B antigen mis-matched cadaveric kidney transplants on graft and patient survival

During the period 1969 to 1978 survival of recipients of 1st cadaveric renal grafts improved. This improvement occurred in spite of a sharp increase in high risk patients accepted for transplantation, including patients with high age, diabetic nephropathy and advanced arteriosclerotic disease. In the same period 1st graft survival decreased. The declining graft prognosis was related to the acceptance of 3-4 HLA-A and B incompatible grafts from 1973 onwards. Grafts with 0-2 incompatibilities had a stable survival during the whole 10-years period. The group of patients receiving grafts with 3-4 incompatibilities, however, included significantly more patients with diabetic nephropathy and age above 55 years. Further analysis demonstrated that the inferior graft prognosis was caused by a combined effect of HLA-mismatched grafts and the number of high risk patients. The distribution of antibodies at retransplantation (2nd graft) was similar whether the lost 1st graft was compatible for 0-2 or 3-4 HLA antigens. Also the prognosis of retransplantation was similar in the two groups.

Stones in renal transplants

In a 50-year-old man (case 1) and a 17-year-old girl (case 2) stones developed in a functioning renal transplant. The respective intervals from transplantation to appearance of stone were seven years and six months. The serum calcium was elevated to approximately 3.00 mmol/l in case 1 and 2.65 mmol/l in case 2. The concentration of parathyroid hormone in serum was increased in case 1. Subtotal parathyroidectomy was performed in both patients, with removal of 2550 mg (case 1) and 150-160 mg (case 2) parathyroid tissue. In case 2 slight hypercalcaemia reappeared two months later. When stones in a transplanted kidney are associated with only slight hypercalcaemia and there is no deterioration of the renal function, conservative measures to reduce the serum calcium should be tried before subtotal parathyroidectomy is undertaken.