Clinical effectiveness and cost-effectiveness of tests for the diagnosis and investigation of urinary tract infection in children: a systematic review and economic model

OBJECTIVES

To determine the diagnostic accuracy of tests for detecting urinary tract infection (UTI) in children under 5 years of age and to evaluate the effectiveness of tests used to investigate further children with confirmed UTI. Also, to evaluate the effectiveness of following up children with UTI and the cost-effectiveness of diagnostic and imaging tests for the diagnosis and follow-up of UTI in children under 5. An additional objective was to develop a preliminary diagnostic algorithm for healthcare professionals.

DATA SOURCES

Electronic databases were searched up to the end of 2002/early 2003. Consultation with experts in the field.

REVIEW METHODS

A systematic review was undertaken using published guidelines and results were analysed according to test grouping: diagnosis of UTI and further investigation of UTI. The cost-effectiveness results from existing evaluations were synthesised. A separate cost-effectiveness model was developed using the best available evidence, in part derived from the results of the systematic review, to illustrate the potential cost-effectiveness of some alternative management strategies in a UK setting. The results of the systematic review were used to propose diagnostic algorithms for the diagnosis and further investigation of UTI in children. Economic analyses did not contribute directly to the development of these algorithms.

RESULTS

The studies included in the review provided very little data on the accuracy of clinical investigations for the diagnosis of UTI, and criteria for clinical suspicion of UTI were not further defined. The majority of studies included in the review found that clean voided midstream urine (CVU) samples had similar accuracy to suprapubic aspiration (SPA) samples when cultured with the advantage of being a non-invasive collection method that can be used in the GP's surgery. Pad, nappy or bag specimens may be appropriate methods for obtaining a urine sample in non-toilet-trained children, although only limited data were available. Although the glucose test was reported to have the highest accuracy in terms of both ruling in and ruling out disease, only a limited number of studies of this test were included and these were conducted over 30 years ago. Dipstick tests are easy to perform in the GP's surgery, give an immediate result and are relatively cheap. The results of the systematic review showed that a dipstick for leucocyte esterase (LE) and nitrite, where both test results are interpreted in combination, was a good test both for ruling in (both positive) and ruling out (both negative) a UTI. A dipstick positive for either LE or nitrite and negative for the other provides inconclusive diagnostic information and further testing is therefore required in these patients. Microscopy is more time consuming and expensive to perform than a dipstick test, but potentially quicker and cheaper than culture. As with dipstick tests, a combination of microscopy for pyuria and bacteriuria can be used accurately to rule in and rule out a UTI. An indeterminate test result is again obtained if microscopy is positive for either pyuria or bacteriuria, and negative for the other. Confirmatory culture is required in these patients. In patients considered to have a UTI, further culture to determine antibiotic sensitivities may be an option to inform treatment decisions. Only one study satisfied the inclusion criteria of the economic review and the review highlighted a number of potential limitations of this study for NHS decision-making. A separate decision-analytic model was therefore developed to provide a more reliable estimate of the optimal strategy regarding the diagnosis and further investigation of children under 5 with suspected UTI from the perspective of the NHS. The economic model found that the optimal diagnostic strategy for children presenting with symptoms suggestive of UTI depends on a number of key factors. These included the relevant subgroup of children concerned, in terms of gender and age, and the health service's maximum willingness to pay for an additional quality-adjusted life-year.

CONCLUSIONS

The results of the systematic review were used to derive an algorithm for the diagnosis of UTI in children under 5. This algorithm represents the conclusions of the review in terms of effective practice. There were insufficient data to propose an algorithm for the further investigation of UTI in children under 5. The quality assessment highlighted several areas that could be improved upon in future diagnostic accuracy studies.

Systematic review of the clinical effectiveness and cost-effectiveness of capecitabine (Xeloda) for locally advanced and/or metastatic breast cancer

OBJECTIVE

To examine the clinical effectiveness and cost-effectiveness of oral capecitabine for locally advanced and metastatic breast cancer in relation to its licensed indications.

DATA SOURCES

Twenty-three electronic databases and other databases of ongoing research and Internet resources, bibliographies of retrieved articles and industry submissions.

REVIEW METHODS

Two reviewers independently screened and assessed all titles and/or abstracts including economic evaluations. Randomised controlled trials (RCTs) and observational studies that investigated capecitabine monotherapy, in patients pretreated with an anthracycline-containing regimen or a taxane, or capecitabine in combination with docetaxel, in patients pretreated with an anthracycline-containing regimen, were included. The economic evaluation was based on data reported in the manufacturer's submission.

RESULTS

For capecitabine monotherapy, 12 uncontrolled observational studies were identified. The methodological quality of the studies was low. Capecitabine demonstrated antitumour activity, but was associated with a particular risk of hand-foot syndrome and diarrhoea. Economic evaluation was hampered by the poor quality of the published studies, but compared indirectly with vinorelbine, capecitabine was associated with lower costs and improved patient outcomes. For capecitabine in combination with docetaxel, one RCT was identified. Combination therapy was superior to single-agent docetaxel in terms of survival, time to disease progression and overall response. Adverse events occurred more frequently with combination therapy. The economic evaluation demonstrated an overall improved QALY score for combination therapy with a slight reduction in costs.

CONCLUSIONS

No conclusions could be drawn regarding the therapeutic benefit of capecitabine monotherapy; RCTs are required. Capecitabine appeared cost-effective compared with vinorelbine, but serious doubts remain; the poor quality of the trials may invalidate this conclusion. Based on limited evidence, combination therapy was more effective than single-agent docetaxel and likely to be cost-effective, but was associated with higher incidences of hand-foot syndrome, nausea, diarrhoea and stomatitis.

Ghrelin concentrations in healthy children and adolescents

OBJECTIVE

In addition to its regulation by GH releasing hormone (GHRH) and somatostatin, release of GH from the pituitary is modulated by a third factor, ghrelin, which is expressed in high concentration in the stomach and is present in the circulation. Ghrelin has also been shown to cause weight gain by increasing food intake and decreasing fat utilization. Ghrelin is a potential candidate hormone to influence nutrient intake and growth. Its role through normal childhood and adolescence has not been fully defined.

DESIGN

Cross-sectional study in 121 healthy children (65 male, 56 female) aged 5-18 years, in whom height, weight, body mass index (BMI), pubertal status and measurements of IGF-I, IGFBP-3, IGFBP-1 and leptin were available.

METHODS

Serum ghrelin concentrations have been measured in radioimmunoassay (RIA; Phoenix, AZ, USA) that detects active and inactive human ghrelin. Relationships between ghrelin and anthropometric data and growth factors were assessed by correlation and regression analyses.

RESULTS

Ghrelin was detected in all samples, with a median concentration of 162 pg/ml, range 60-493 pg/ml. Prepubertal children had higher ghrelin concentrations than those in puberty [218 pg/ml (n = 42) and 157 pg/ml (n = 79), P < 0.001], with significant negative correlations between ghrelin and age (rs = -0.39, P < 0.001) and pubertal stage (rs = -0.42, P < 0.001). The decrease in ghrelin with advancing pubertal stage/age was more marked in boys than girls. In the whole group, ghrelin was negatively correlated to BMI SD (rs = -0.24, P = 0.006) and to weight SD (rs = -0.24, P = 0.008) but not height sds. Ghrelin was also negatively correlated to IGF-I (rs = -0.48, P < 0.001), IGFBP-3 (rs = -0.32, P < 0.001) and leptin (rs = -0.22, P = 0.02) but not IGF-II. It was positively related to IGFBP-1 (rs = +0.46, P < 0.001). In stepwise multiple regression, 30% of the variability in ghrelin through childhood could be accounted for by log IGF-I (24%) and log IGFBP-1 (6%).

CONCLUSIONS

The fall in ghrelin over childhood and with puberty does not suggest that it is a direct growth-promoting hormone. However in view of the negative relationship with IGF-I and the positive relationship with IGFBP-1, this fall in ghrelin could facilitate growth acceleration over puberty.

IGF-binding protein-1 inhibits IGF effects on adipocyte function: implications for insulin-like actions at the adipocyte

IGF action in vivo is acutely regulated by IGF-binding protein-1 (IGFBP-1) and its phosphorylation state is implicated in modulating these effects. Since IGFs have an important regulatory role in adipocyte function, we investigated the effects of phosphorylated IGFBP-1 (pIGFBP-1) and non-phosphorylated IGFBP-1 (npIGF BP-1) on 3T3-L1 preadipocyte proliferation and adipocyte metabolism. IGFs stimulated clonal expansion of 3T3-L1 cells (IGF-I more potently than IGF-II (EC(50): 30 nM and 50 nM)). npIGFBP-1 inhibited IGF-I (50 nM) clonal expansion at a 5:1 molar ratio (P<0.01), whereas pIGFBP-1 (purified from HepG2 cell medium) abolished clonal expansion at a 1:1 molar ratio (P<0.005). In contrast, IGF-II-induced clonal expansion was inhibited 100% at a 1:1 molar ratio of npIGFBP-1. In mature adipocytes, IGF-I was equipotent with insulin in stimulating glucose uptake (EC(50): 10 nM) and inhibiting isoproterenol-induced lipolysis (EC(50): 15 nM). npIGFBP-1 completely reversed IGF-I effects at a 1:1 molar ratio (P<0.01). In summary, IGFs rather than insulin are potent regulators of clonal expansion in 3T3-L1 preadipocytes. Importantly, IGFs are equipotent with insulin in regulating adipocyte metabolism. IGFBP-1 inhibits IGF effects on preadipocyte proliferation and adipocyte metabolism, with pIGFBP-1 being more potent than npIGFBP-1 at inhibiting mitogenic actions. Since IGFBP-1 is acutely regulated by insulin, this could have important consequences in hyperinsulinaemic and insulin-resistant states.

alpha 2-Macroglobulin: a new component in the insulin-like growth factor/insulin-like growth factor binding protein-1 axis

Insulin-like growth factors (IGFs) are crucial for many aspects of development, growth, and metabolism yet control of their activity by IGF-binding proteins (IGFBPs) remains controversial. The effect of IGFBP-1 depends on its phosphorylation status; phosphorylated IGFBP-1 inhibits IGF actions whereas the nonphosphorylated isoform is stimulatory. In order to understand this phenomenon, we purified phosphorylated IGFBP-1 from normal human plasma by immunoaffinity chromatography. Unexpectedly, the resulting preparation enhanced IGF-stimulated 3T3-L1 fibroblast proliferation, due to the presence of a co-purified protein of approximately 700 kDa. Matrix-assisted laser desorption ionization-mass spectrometry and Western immunoblotting analysis identified this co-purified protein as alpha(2)-macroglobulin (alpha(2)M). Anti-alpha(2)M antibodies co-immunoprecipitated IGFBP-1 from human plasma and from (125)I-IGFBP-1.alpha(2)M complexes formed in vitro. The (125)I-IGFBP-1/alpha(2)M association could be inhibited with excess unlabeled IGFBP-1. Surface plasmon resonance analysis indicated that alpha(2)M preferentially associates with the phosphorylated isoform of IGFBP-1 and that when complexed to alpha(2)M, IGFBP-1 can still bind IGF-I. These findings have functional significance since alpha(2)M protects IGFBP-1 from proteolysis and abrogates the inhibitory effect of phosphorylated IGFBP-1 on IGF-I stimulated 3T3-L1 cell proliferation. We conclude that alpha(2)M is a binding protein of IGFBP-1 which modifies IGF-I/IGFBP-1 actions resulting in enhanced IGF effects. In line with its role in regulating the clearance and activity of other growth factors, we predict that alpha(2)M has a novel and important role in controlling the transport and biological activity of IGFs.

Placental regulation of insulin-like growth factor axis in monochorionic twins with chronic twin-twin transfusion syndrome

To test the hypothesis that severe growth restriction (intrauterine growth retardation) in donor twins with chronic twin-twin transfusion syndrome (TTTS), a common complication of monochorionic twin pregnancy, is due to an aberration in the insulin-like growth factor (IGF) axis, we studied 25 sets of monochorionic twins with (n = 13) and without (n = 12) TTTS. Maternal and cord blood samples were collected at birth and analyzed for IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), and IGFBP-1 phosphorylation status. Fetal IGF-II levels in the recipient twins with TTTS were higher than those in the donor twins (829 +/- 45 vs. 543 +/- 60 ng/mL; P < 0.001), but were comparable with those in the non-TTTS twin pairs. IGF-I levels in recipient and donor twin pairs were similar. The total IGFBP-1 concentration was higher in the donor twins than in the recipients (1153 +/- 296 vs. 419 +/- 108 ng/mL; P < 0.001) and non-TTTS twin pairs (P < 0.01). The percent less phosphorylated IGFBP-1 was higher in the recipients than in the donor twins (P < 0.05). There were no differences in IGF-I, IGF-II, and IGFBP-1 levels between non-TTTS twin pairs. Maternal levels of IGFs were comparable in the two groups. In the TTTS group, fetal birth weight gave a positive correlation with serum IGF-II levels (y = 0.25x + 361.1; r = 0.47; P < 0.05), and a negative association with IGFBP-1 levels (y = -0.72x + 1593.6; r = 0.58; P < 0.01). Our data argue against intertwin transfusion as the cause of intrauterine growth retardation in the donor twin and provide evidence that the placenta is the key regulator of the fetal IGF axis, especially when fetal genotype and maternal environments are similar.

Genes or placenta as modulator of fetal growth: evidence from the insulin-like growth factor axis in twins with discordant growth

To determine whether fetal growth is regulated by placental and/or fetal factors, we measured maternal and fetal concentrations of insulin-like growth factor-I (IGF-I), IGF-II and insulin-like growth factor binding protein-1 (IGFBP-1) (total and non-phosphorylated) in dichorionic (DC) and monochorionic (MC) twins with (DC, n = 13; MC, n = 12) or without (DC, n = 13; MC, n = 12) discordant birth weight. In the discordant MC pregnancy, growth-restricted (IUGR) twins had lower IGF-II concentrations (P < 0.001) but similar IGF-I concentrations compared to the appropriate for gestational age(AGA) co-twin. The differences in IGF-II concentrations showed a positive association with percentage birth weight discordance (r = 0.60; P < 0.05) in MC twins. In contrast, IUGR DC twins had lower IGF-I concentrations (P < 0.05) but similar IGF-II concentrations compared to the AGA co-twins. There was a positive correlation between IGF-I concentrations and birth weight (r = 0.47; P < 0.05) in DC twins. Total IGFBP-1 concentrations were higher in both MC and DC IUGR twins (P < 0.05) compared to AGA twins. A negative association was found between total IGFBP-1 concentrations and birthweight of both MC (r = 0.47; P < 0.05) and DC (r = 0.58; P < 0.01) twins. No such differences in IGF concentrations were found between concordant MC and DC twin pairs. The maternal IGF concentrations were comparable between the MC and DC groups. These data suggest that growth discordances of twins exposed to the same maternal environment may be due to variations in either IGF-I or IGF-II/IGFBP-1, depending upon the functioning of the placenta.

Monoclonal antibodies to the carboxy-terminal Ea sequence of pro-insulin-like growth factor-IA (proIGF-IA) recognize proIGF-IA secreted by IM9 B-lymphocytes

Insulin-like growth factor-I (IGF-I) circulates in human serum as a 7 kDa peptide but analysis of IGF-I cDNAs predicts two pro-hormone precursors (proIGF-IA and proIGF-IB) with distinct C-terminal E domains. The function of these precursors, and the E peptides generated on cleavage to mature IGF-I, is unknown, largely because of a lack of tools for distinguishing precursors from constituent peptides. We used a synthetic Ea peptide to develop monoclonal antibodies (MAbs) which can recognize the carboxy-terminal sequence of proIGF-IA. These were characterized using proIGF-IA generated by transfected HEK293 cells. The anti-proIGF-IA MAbs immunoprecipitated two peptides (19--21 and 14 kDa) which were also recognized by MAbs to mature IGF-I. The proIGF-IA MAbs could also detect peptides of 9 and 4 kDa predicted to be Ea peptides. Treatment with N -glycosidase proved the 19--21 kDa and 9 kDa bands to be glycosylated proIGF-IA and Ea peptide respectively. Using these antibodies, we have identified proIGF-IA secreted from the IM9 B-lymphocyte cell line. This work paves the way for studies on proIGF-IA and Ea peptide regulation and function.

Regulation of IGF bioavailability in pregnancy

During pregnancy, insulin-like growth factors (IGFs) are important for growth of fetal and maternal tissues. One of the IGF binding proteins, IGFBP-1, is thought to regulate their activity within the local environment of the placenta. IGFBP-1 usually exists as a phosphorylated, high affinity species, which sequesters IGFs, thereby inhibiting their actions. This study has investigated the mechanisms that release IGF from IGFBP-1 at the maternal-fetal interface. Under basal conditions, human decidualized endometrium produces both non-phosphorylated (np) and phosphorylated (p) isoforms of IGFBP-1; however, in the presence of IGF-II, which is a trophoblast secretory product, npIGFBP-1 was preferentially produced. Furthermore, we found that trophoblast, presumably via placental alkaline phosphatase, can de-phosphorylate pIGFBP-1. Since npIGFBP-1 has decreased affinity for IGF-I, these effects should enhance IGF-I bioavailability. In addition, we found that decidual cells produce a protease, which cleaves IGFBP-1, but only when it is non-phosphorylated; [(125)I]-npIGFBP-1 is proteolysed into 14 and 17 kDa fragments which have markedly reduced affinity for IGF. We therefore propose paracrine modulation of IGFBP-1 at the maternal-fetal interface involving a multi-step process of de-phosphorylation and proteolysis; this will result in enhanced IGF bioavailability and is likely to represent an important mechanism for controlling fetal and maternal tissue growth.

Growth factor-extracellular matrix synergy in the control of trophoblast invasion

At the periphery of the human placenta, trophoblast attaches to the uterine wall. The tissue interface contains many anchoring sites, with cytotrophoblast columns that form bridges between the overlying extraembryonic (villous) mesenchyme and the maternal decidual stroma beneath. From the periphery of these columns, large numbers of trophoblast cells detach, migrate through the decidua and eventually colonize and transform maternal arteries. In this way the placenta increases and gives priority to the maternal blood supply to the conceptus. We have shown that when early villous tissue is explanted on a collagen gel in serum-free medium, anchoring-site morphogenesis occurs. Thus, in the presence of placental mesenchyme but in the absence of maternal cells, contact with a permissive extracellular matrix (ECM) is necessary and sufficient for cytotrophoblast column development. Proliferation of trophoblast occurs, followed by differentiation into a columnar cell phenotype in which cells remain attached to one another and to the ECM. At this stage, interaction between fibronectin and integrin alpha5beta1 at the cell surface stabilizes the column and the cells remain as a contiguous multilayered sheet. However, the addition of serum-free conditioned medium from first-trimester placental fibroblasts stimulates cytotrophoblast to detach from the distal column and migrate in streams across the ECM. The removal of insulin-like growth factor I (IGF-I) from the fibroblast medium decreases streaming activity, whereas the addition of exogenous IGF-I (10 ng/ml) to serum-free medium produces a streaming phenotype. In contrast, transforming growth factor beta1 (10 ng/ml) maintains the cells in a tight sheet. These results suggest the possibility of a paracrine interaction between villous mesenchyme and cytotrophoblast in anchoring sites to stimulate the infiltration of the maternal ECM by trophoblast. Such a mechanism would be self-limiting because the signal diminishes with distance from the placenta.

Association of elevated insulin-like growth factor binding protein-1 with insulin resistance in hyperthyroidism

OBJECTIVE

Insulin-like growth factor binding-protein-1 (IGFBP-1) has a role in glucose homeostasis and is present at high concentrations in hyperthyroidism. We have investigated the relationship between IGFBP-1 concentration and glucose homeostasis in hyperthyroidism.

DESIGN

Patients and controls had intravenous glucose tolerance tests (IVGTT) and/or oral glucose tolerance tests (OGTT). Patients were tested when hyperthyroid and when euthyroid whilst the controls were tested once. The IVGTT was used to assess insulin sensitivity and the OGTT to establish that the study group had abnormal glucose tolerance. The hyperthyroid patients were treated with methimazole to restore euthyroidism.

PATIENTS

Ten patients (9 females) and 13 healthy controls (9 females) consented to the study. Ten patients and nine controls (7 females) had IVGTT. Six patients (5 females) and six controls (4 females) had OGTT.

MEASUREMENTS

Glucose, insulin, glucagon, GH and IGFBP-1 were measured during GTT. IGF-I, free thyroid hormones, and TSH concentrations were measured basally.

RESULTS

Hyperthyroid subjects were insulin resistant and 67% had impaired glucose tolerance. Fasting IGFBP-1 levels were doubled in hyperthyroid subjects compared to healthy controls and correlated positively with free T4 (r = 0.84, P < 0.0001), with peak glucose during the OGTT (r = 0.68, P < 0.005) with peak insulin during the IVGTT (r = 0.51, P < 0.005) and negatively with glucose disappearance constant (r = - 0.52, P < 0.005). IGFBP-1 was highly phosphorylated in hyperthyroid and control subjects. Fasting insulin and IGFBP-1 levels were unrelated but IGFBP-1 suppressed acutely during GTT in all groups. GH levels fell less in patients with hyperthyroidism than in normals during GTTs.

CONCLUSIONS

We conclude that in hyperthyroidism thyroid hormones directly increase fasting IGFBP-1 concentration but acute regulation of IGFBP-1 by insulin is normal and that elevated fasting phosphorylated IGFBP-1 concentration is associated with insulin resistance.

Role of insulin-like growth factor binding protein 1 in human pregnancy

Insulin-like growth factors and their binding proteins are key regulators of fetal and maternal tissue growth and development during human pregnancy. Insulin-like growth factors, particularly IGF-II, are produced in abundance by the trophoblast cells of the placenta, whereas one of the insulin-like growth factor binding proteins, IGFBP-1, is the major secretory product of the maternal decidualized endometrium. This spatial (and temporal expression) of the insulin-like growth factor axis infers a sophisticated paracrine regulatory mechanism for controlling insulin-like growth factor function. This paper reviews the potential roles of IGFBP-1 in human pregnancy by examining its effects on growth, metabolism and migration at the maternal-fetal interface and how these might be influenced by autocrine-paracrine post-translational modifications.

Modification of plasma insulin-like growth factors and binding proteins during oral contraceptive use and the normal menstrual cycle

OBJECTIVE

Sex steroid regulation of the insulin-like growth factor axis is a subject of contention. We examined the effect of combined oral contraceptives and investigated the cyclic variations in the insulin-like growth factor axis.

STUDY DESIGN

Fasting blood samples were taken from 9 women receiving oral contraceptives, 10 women receiving no medication, and 10 male subjects.

RESULTS

In women receiving oral contraceptives, insulin-like growth factor binding protein 1 remained highly phosphorylated and levels were acutely increased by sex steroid treatment (305 +/- 110 microg/L on day 14 of the cycle [medication phase] vs 118 +/- 70 microg/L during the medication-free period, P <.03). In women receiving no medication, insulin-like growth factor binding protein 1 levels were significantly lower (69 +/- 50 microg/L on day 14 of the menstrual cycle, P <.001) and varied cyclically, with a rise in the late-secretory phase that coincided with the appearance of nonphosphorylated and less phosphorylated insulin-like growth factor binding protein 1 isoforms. Compared with those in untreated women and in men, insulin-like growth factor I levels were decreased in women receiving oral contraceptives (405 +/- 104 ng/mL in untreated women and 330 +/- 28 ng/mL in men vs 287 +/- 73 ng/mL in women receiving oral contraceptives, P <.004). Oral contraceptive use had no effect on insulin-like growth factor II levels, and neither insulin-like growth factor I nor insulin-like growth factor II showed cyclic variation.

CONCLUSION

The bioavailability of insulin-like growth factor I is reduced in users of oral contraceptives. This may contribute to the metabolic changes observed in such subjects.

Phosphorylated insulin-like growth factor binding protein 1 is increased in pregnant diabetic subjects

During pregnancy, IGFs and their binding proteins (IGFBPs) are important for the growth of fetal and maternal tissues. IGFBP-1 normally circulates as a single, highly phosphorylated species (hpIGFBP-1). However, in pregnancy there are lesser phosphorylated isoforms (lpIGFBP-1) with decreased affinity for IGF-I, allowing for increased IGF bioavailability. Because regulation of IGFBP-1 is abnormal in type 1 diabetes, we examined the impact of this on IGFBP-1 and its phosphorylation status in diabetic pregnancy. We assessed IGFBP-1 in relation to birth weight, maternal weight gain, duration of diabetes, glycemic control, and the presence or absence of retinopathy in 44 diabetic and 11 nondiabetic subjects. We found that in type 1 diabetic patients there was a significant negative relationship between hpIGFBP-1 and birth weight (r = -0.42, P < 0.01) and between the ratio of hpIGFBP-1 to lpIGFBP-1 and birth weight (r = -0.38, P = 0.02) by week 18 of gestation. Multiple regression analysis confirmed that hpIGFBP-1 was the best single predictor of birth weight (R2 = 0.3, P = 0.001) in diabetic subjects using models including other parameters known to influence fetal size. In contrast to hpIGFBP-1 levels, lpIGFBP-1 levels were not associated with birth weight, but were significantly related to initial maternal BMI and maternal weight throughout gestation in diabetic subjects (r = -0.57, P < 0.001). hpIGFBP-1 levels were positively related to duration of diabetes (r = 0.38, P < 0.01). Diabetic subjects had significantly higher hpIGFBP-1 and lpIGFBP-1 levels than nondiabetic subjects (hpIGFBP-1: 215 +/- 21 vs. 108 +/- 13 microg/l, P = 0.01; lpIGFBP-1: 139 +/- 12 vs. 66 +/- 5 microg/l, P < 0.001), but the ratio of hpIGFBP-1 to lpIGFBP-1 was similar in both groups (2.1 +/- 0.3 [diabetic] vs. 1.7 +/- 0.2 [nondiabetic], NS). In summary, maternal IGFBP-1 levels were higher in diabetic than in normal pregnancies. Diabetic subjects with prolonged duration of diabetes and retinopathy had higher total IGFBP-1 levels than those with shorter disease duration. Thus hpIGFBP-1 in diabetic pregnancy is positively related to the duration of diabetes and inversely related to fetal growth, with lpIGFBP-1 being related to maternal weight and BMI. The ratio of hpIGFBP-1 to lpIGFBP-1 may be a more robust indicator of fetal outcome, since it was consistent between diabetic and nondiabetic subjects. Measurement of the different phosphorylated isoforms of IGFBP-1 may increase the usefulness of IGFBP-1 as a predictor of fetal growth in both normal and diabetic pregnancy.

The ratio of erythrocyte zinc-protoporphyrin to protoporphyrin IX in disease and its significance in the mechanism of lead toxicity on haem synthesis

Protoporphyrin and zinc-protoporphyrin were measured in the erythrocytes of normal subjects, workers exposed to lead and patients with iron deficiency and erythropoietic protoporphyria (EPP). Results showed significantly higher levels of zinc-protoporphyrin in the lead-exposed workers (P < 0.0001), patients with iron deficiency (P < 0.0001) and EPP patients (P < 0.001) compared with normal subjects. The lead-exposed workers showed the highest levels of zinc-protoporphyrin, which were significantly greater than both the iron-deficient and EPP patients (P < 0.0001). They also showed a higher ratio of zinc-protoporphyrin to free protoporphyrin compared with normal subjects (P < 0.0001) but no significant difference in this ratio was found when compared with iron-deficient patients (P = 0.1). These results are discussed in light of the controversy concerning the mechanism of formation of zinc-protoporphyrin in lead exposure.

Insulin-like growth factor binding protein concentration and post-translational modification in embryological fluid

Levels of proteolytic activity directed against insulin-like growth factor binding protein 3 (IGFBP-3) and the distribution of phosphorylated isoforms of IGFBP-1 were assessed in matched sample sets of maternal serum, coelomic fluid and amniotic fluid from 21 pregnancies at 6-12 weeks gestation. In addition, concentrations of immunoreactive IGFBP-1 to -3, insulin-like growth factor (IGF)-I and -II were determined in all three compartments in 21 pregnancies, and in coelomic fluid and maternal serum in 58 pregnancies. IGF-I concentrations were highest in maternal serum and similarly low in coelomic and amniotic fluid. IGF-II concentrations were also highest in maternal serum but easily detectable in coelomic fluid where concentrations showed a significant correlation with gestational age. IGFBP-1 concentrations were higher in coelomic fluid than in either maternal serum or amniotic fluid and showed a significant correlation with gestational age in this compartment. Analysis of IGFBP-1 phosphoforms showed clear differences in phosphorylation of IGFBP-1 between groups with maternal serum containing predominantly the phosphorylated forms and coelomic fluid almost exclusively the non-phosphorylated form. First trimester amniotic fluid IGFBP-1 was barely detectable and appeared non-phosphorylated. These findings suggest that the high IGF-II concentrations and lack of inhibitory phosphoforms of IGFBP-1 in coelomic fluid could potentially enhance mitogenic activity in the early human gestational sac. IGFBP-2 concentrations were high in coelomic fluid compared with maternal serum whereas coelomic fluid IGFBP-3 concentrations were intermediate, easily detectable and correlated strongly with gestational age. Protease activity was far less in coelomic fluid than in matched maternal serum samples. Marked differences in both concentrations and post-translational modification of IGFBPs in maternal serum compared with embryonic fluid suggest different regulatory pathways.

Purification and characterization of the insulin-like growth factor-binding protein-1 phosphoform found in normal plasma

Our previous work has shown that, in the normal circulation, insulin-like growth factor-binding protein-1 (IGFBP-1) is present as a single highly phosphorylated species. In this study, we have purified this previously uncharacterized isoform of IGFBP-1 to determine its ligand-binding affinity and the potential significance of highly phosphorylated IGFBP-I. Immunoaffinity chromatography was used to isolate IGFBP-1 from normal human plasma and from human hepatoma (Hep G2) cell medium as an alternative source of the IGFBP-1 phosphoform in the circulation. The affinity of this highly phosphorylated IGFBP-1 was compared with that of nonphosphorylated IGFBP-1 and recombinant human (rh) IGFBP-3 by equilibrium binding to IGF-II and IGF-II. Anion exchange (IEX) HPLC, nondenaturing electrophoresis, alkaline phosphatase treatment, and ligand-binding studies indicated that the highly phosphorylated IGFBP-1 from HepG2 cells was comparable with IGFBP-1 from plasma. In binding to IGF-I, the plasma phosphoform of IGFBP-1 was found to have a higher affinity (2.3 +/- 1.1 x 10(10) M-1) than nonphosphorylated IGFBP-1 (2.5 +/- 1.7 x 10(9) M-1, P < 0.002). However, when binding to IGF-II, phosphorylation had no affect on the affinity of IGFBP-1 (3.6 +/- 2 x 10(9) M-1 vs. 1.8 +/- 3 x 10(9) M-1, P not significant). Therefore, in the circulation, IGF-I has a considerably higher affinity than IGF-II for IGFBP-1 (P < 0.02). The affinity of phosphorylated IGFBP-1 from plasma (2.3 +/- 1.1 x 10(10) M-1) also was significantly higher than the affinity of IGFBP-3 for IGF-I (5.6 +/- 4.2 x 10(9) M-1, P < 0.005). These data suggest that the highly phosphorylated IGFBP-1 in the normal circulation will preferentially bind IGF-I rather than IGF-II, whereas in pregnancy, the affinity of IGFBP-1 for IGF-I will be reduced because of the appearance of non- and lesser-phosphorylated forms. This lends support to the theory that changes in IGFBP-1 phosphorylation may influence the modulatory effects of IGFBP-1 on IGF bioavailability.

The maternal insulin-like growth factor (IGF) and IGF-binding protein response to trisomic pregnancy during the first trimester: a possible diagnostic tool for trisomy 18 pregnancies

Many lines of evidence point to an important role for the insulin-like growth factors (IGFs) in embryonic and fetal growth in human pregnancy. The bioavailability of IGFs is modulated by IGF-binding proteins (IGFBP-1 to -6), whose permissive or inhibitory actions are regulated in part by posttranslational modification. In second and third trimester pregnancies, maternal IGFBP-1 is elevated in preeclampsia and intrauterine growth retardation. In the first trimester, trisomic pregnancies result in derangement of maternal serum levels of peptides, including hCG beta and pregnancy-associated plasma protein A. Trisomy 18 is characterized by growth failure in the first trimester, whereas trisomy 21 is not; thus, if maternal serum levels of IGFs and IGFBPs reflect fetal growth, changes specific to trisomy 18 may be expected. We report maternal serum levels of IGF-I, IGF-II, and IGFBP-1,-2, and -3; IGFBP-1 phosphorylation; and IGFBP-3 proteolysis in pregnancies (n = 139) complicated by trisomy 18 or trisomy 21 compared with those in normal controls. Maternal IGF-I, IGF-II, and IGFBP-3 showed no significant difference between fetuses with a normal karyotype and those with trisomy 18 or 21. The mean IGFBP-1 level was significantly higher and the mean IGFBP-2 level was lower in fetuses with trisomy 18 compared with normal fetuses [108.8 +/- 6.1 vs. 36.7 +/- 1.9 micrograms/L (P = 0.0001) and 81.2 +/- 5.5 vs. 206.1 +/- 10.2 micrograms/L (P = 0.0001), respectively]. There was no significant difference between the trisomy 21 and normal groups. The reduction in IGFBP-2 was confirmed by Western ligand and immunoblotting, and there was no evidence of variation in lower mol wt products to suggest differential proteolysis. IGFBP-1 phosphoforms and IGFBP-3 proteolysis were not significantly different between groups. The finding of altered maternal serum levels of IGFBP-1 and IGFBP-2 specific to pregnancies complicated by trisomy 18 suggests that these binding proteins may be important mediators of fetal growth in the first trimester, and the clear differences in the ratio of IGFBP-1 to -2 may serve as an additional diagnostic marker for trisomy 18 pregnancies.

Expression of the angiogenic factor thymidine phosphorylase/platelet-derived endothelial cell growth factor in primary bladder cancers

Thymidine phosphorylase (TP), also known as platelet-derived endothelial cell growth factor, has been implicated in bladder cancer angiogenesis. To examine its role more clearly, we have quantified and localized its expression using Western analysis and immunohistochemistry in a series of 105 bladder cancers. We have also assessed the relationship between TP expression and other tumor parameters including quantitative angiogenesis, p53 status, ploidy, and survival. By Western analysis, TP expression was 5-fold higher in tumors than in normal bladder samples (P < 0.02). Expression was 15-fold higher in invasive tumors than in normal bladder (P < 0.001) and 8-fold higher than in superficial tumors (P < 0.005). Immunohistochemistry of the tumors showed TP was present in the neoplastic epithelium in 27% of the tumors, in the inflammatory cells in 72% of the tumors, in stromal cells in 30% of the tumors, and in tumor-associated endothelium in 11% of the tumors. Expression by Western blotting and immunohistochemistry was significantly up-regulated in tumors compared with normal bladder (P < 0.05). Tumor cell TP expression correlated with tumor grade (P < 0.02), but there was no correlation between tumor cell TP expression and tumor stage (P = 0.46), ploidy (P = 0.52), p53 expression (P = 0.9), tumor vascularity (P = 0.8), relapse-free survival (P = 0.57), or overall survival (P = 0.94). TP protein is expressed in bladder cancers, and expression is associated with an aggressive phenotype. Because TP can activate a number of cytotoxic agents, it provides a potential therapeutic target in bladder cancer.

The angiogenic factor platelet-derived endothelial cell growth factor/thymidine phosphorylase is up-regulated in breast cancer epithelium and endothelium

Tumour angiogenesis is a complex multistep process regulated by a number of angiogenic factors. One such factor, platelet-derived endothelial cell growth factor has recently been shown to be thymidine phosphorylase (TP). TP catalyses the reversible phosphorylation of thymidine to deoxyribose-1-phosphate and thymine. Although known to be generally elevated in tumours, the expression of this enzyme in breast carcinomas is unknown. Therefore, we used ribonuclease protection assays and immunohistochemistry to examine the expression of TP in 240 primary breast carcinomas. Nuclear and/or cytoplasmic TP expression was observed in the neoplastic tumour epithelium in 53% of tumours. Immunoreactivity was also often present in the stromal, inflammatory and endothelial cell elements. Although endothelial cell staining was usually focal, immunoreactivity was observed in 61% of tumours and was prominent at the tumour periphery, an area where tumour angiogenesis is most active. Tumour cell TP expression was significantly inversely correlated with grade (P = 0.05) and size (P = 0.003) but no association was observed with other tumour variables. These findings suggest that TP is important for remodelling the existing vasculature early in tumour development, consistent with its chemotactic non-mitogenic properties, and that additional angiogenic factors are more important for other angiogenic processes like endothelial cell proliferation. Relapse-free survival was higher in node-positive patients with elevated TP (P = 0.05) but not in other patient groups. This might be due to the potentiation of chemotherapeutic agents like methotrexate by TP. Therefore, this enzyme might be a prediction marker for response to chemotherapy.

Reduced insulin-like growth factor binding protein-1 (IGFBP-1) levels correlate with increased cardiovascular risk in non-insulin dependent diabetes mellitus (NIDDM)

IGF-I and -II levels are altered in patients with atherogenic lipid profiles and may contribute to the development of macrovascular disease in NIDDM. We examined cardiovascular risk factors, IGF-I, IGF-II and IGFBP-1 in 74 NIDDM patients analysed as a whole group and according to treatment type. IGF-I was not significantly associated with cardiovascular risk factors but IGF-II levels correlated positively with total and LDL cholesterol most markedly in the diet treated group (0.72, p < 0.01 and 0.76, p < 0.01 respectively). In the whole group reduced IGFBP-1 levels were significantly associated with factors known to increase cardiovascular risk: i.e. low HDL cholesterol (0.31, p < 0.01) and elevated blood pressure (-0.35, p < 0.01), BMI (-0.37, p < 0.01), insulin (-0.29, p < 0.01) and proinsulin (-0.24, p < 0.01). In the treatment groups IGFBP-1 was lower in patients on diet alone (n = 11, 42.6 +/- 11.6 mu g/l) and sulphonylurea +/- insulin (n = 39, 53.2 +/- 7.6 mu g/l) relative to insulin treatment (n = 24, 103.0 +/- 19, 7 mu g/l, p < 0.05). The lower levels of IGFBP-1 were not due to a significant change in phosphorylation status from the highly phosphorylated circulating form since lesser and non-phosphorylated variants were undetectable in 53/74 patients. Multiple regression analysis revealed the best predictors of IGFBP-1 were BMI and MAP (R2 = 0.2. p < 0.001) and for blood pressure, IGFBP-1 and age (R2 = 0.47, p < 0.001). These findings indicate that in NIDDM patients low IGFBP-1 levels are associated with multiple factors predisposing to atherogenesis.

Hormonal regulation of circulating insulin-like growth factor-binding protein-1 phosphorylation status

Insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) normally circulates as a single, highly phosphorylated species. However, IGFBP-1 phosphorylation status can be altered, such as in pregnancy where non- and lesser phosphorylated isoforms are also present. We have examined how hormonal regulators of circulating IGFBP-1 influence its phosphorylation status and, hence, its ability to modulate IGF activity. In response to insulin-induced hypoglycemia (0.2 U/kg, iv), an increase in the highly phosphorylated isoform was observed after 5 h [16 (range, 11.5-35.5) to 77 (range, 63-250) microgram/L; 4.8-fold increase; P = 0.009], but no non- or lesser phosphorylated variants could be detected. Glucagon (1 mg, sc), increased IGFBP-1 from 27 (range, 13-36.5) to 112 (range, 100.5-129) micrograms/L (4.1-fold increase; P = 0.009) after 90 min despite preceding insulin concentrations of more than 500 pmol/L, but again the IGFBP-1 remained in the highly phosphorylated form. Regulation of IGFBP-1 phosphorylation by sex steroids was studied by comparing women receiving a combined oral contraceptive with women on no medication. Although plasma IGFBP-1 levels were significantly elevated in the treatment group [120 (range, 97.5-237.5) vs. 52 (range, 38-70) micrograms/L; P < 0.004], there was no difference in the form of IGFBP-1 present. The acute effect of somatostatin (500 micrograms/h) on IGFBP-1 phosphorylation status was also studied. Somatostatin only increased the phosphoform characteristic of normal subjects; the appearance of non- or lesser phosphorylated variants was not induced. The effect of rhIGF-I (80 or 120 micrograms, sc) on plasma IGFBP-1 was studied in three subjects with Laron's syndrome. A transient increase in the highly phosphorylated isoform of IGFBP-1 was noted; there was no rise in the non- and lesser phosphorylated isoforms also found in the plasma of Laron's syndrome subjects. These data suggest that only the highly phosphorylated species of IGFBP-1 is under hormonal control; regulation of the non- and lesser phosphorylated variants remains to be determined.

Platelet-derived endothelial cell growth factor/thymidine phosphorylase expression in normal tissues: an immunohistochemical study

Angiogenesis is the formation of new blood vessels from the existing vascular bed. It is a complex multi-step process controlled by a number of angiogenic factors. One such factor is platelet-derived endothelial cell growth factor (PD-ECGF), recently shown to be thymidine phosphorylase (TP), which is angiogenic in several in vivo assays and tumour systems. PD-ECGF/TP catalyses the reversible phosphorylation of thymidine to deoxyribose-1-phosphate and thymine. Since PD-ECGF/TP has an important role in cellular metabolism and in angiogenesis and its expression has been only partially characterized, we raised a monoclonal antibody against recombinant PD-ECGF/TP and used an immunohistochemical approach to examine the expression of PD-ECGF/TP in a comprehensive range of normal human tissues. The clone P-GF44.C, which recognizes recombinant PD-ECGF/TP and cell lysates transfected with a plasmid expressing PD-ECGF/TP cDNA on Western blotting, was selected for its ability to stain routinely processed tissue. Staining was observed in both the cytoplasm and/or the nucleus. Immunoreactivity was strongly expressed by macrophages, stromal cells, glial cells, and some epithelia. Gastrointestinal epithelium, smooth muscle, adrenal, lung, and testis were negative. Although endothelial cell expression was observed, there was no correlation with sites of new vessel growth. This pattern of expression suggests tight PD-ECGF/TP regulation and that cellular thymidine pools may serve to control its different functions. Thus, in the nucleus it might modulate the pool for DNA synthesis, whilst in the cytoplasm it could control other effects through different enzyme systems. The high expression present in macrophages and skin might be important for total body thymidine homeostasis.

Choice of treatment affects plasma levels of insulin-like growth factor-binding protein-1 in noninsulin-dependent diabetes mellitus

Insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) modulates the metabolic and mitogenic effects of IGFs. Although IGFBP-1 levels are abnormally high in insulin-dependent diabetes (IDDM), relatively little is known in NIDDM; conflicting data have suggested both high and low levels. We investigated whether treatment modifies IGFBP-1 levels in two groups of NIDDM patients. Study 1 examined fasting concentrations in groups of patients with NIDDM, comparable except for treatment type (sulfonylurea, n = 23; once daily insulin, n = 15; sulfonylurea plus once daily insulin, n = 14; multiple insulin injections, n = 9) and 25 nondiabetic subjects. In sulfonylurea-treated patients there were markedly reduced plasma IGFBP-1 concentrations (median, interquartile range in parentheses): control, 61.0 (36-96) micrograms/L; sulfonylureas alone, 31.5 (21-61) micrograms/L (P < 0.01); and sulfonylureas plus insulin, 31.5 (9-53) micrograms/L (P < 0.01). Once daily insulin was associated with values similar to those in the control group [62.0 (27-103) micrograms/L; P = NS], whereas IGFBP-1 levels were higher with multiple insulin injection therapy [156.0 (71-184) micrograms/L; P < 0.05]. Proinsulin levels were higher in sulfonylurea-treated patients, but there was no significant correlation between IGFBP-1 and proinsulin within any individual group. Study 2 examined the effects of treatment on the dynamics of IGFBP-1 levels between 0800-1900 h. In control subjects (n = 8), levels fell from 0800 h (mean +/- SEM, 22.4 +/- 5.2 micrograms/L) to 1000 h (14 +/- 5.2 micrograms/L), followed by a rise, more rapid after food, to a peak at 1240 h (20.6 +/- 3.7 micrograms/L). Levels then declined until 1500 h (10.7 +/- 2.9 micrograms/L), with a further postprandial peak at 1840 h (23.1 +/- 3.2 micrograms/L). Sulfonylurea therapy (n = 6) resulted in a complete loss of this pattern, with a marked fall in IGFBP-1 from 0800 h (22 +/- 2.7 micrograms/L) to less than 7 micrograms/L for the remainder of the study (area under the curve, 1150-1400 h, P < 0.001 vs. control). By contrast, in metformin-treated patients (n = 7), neither IGFBP-1 levels nor postprandial peaks were significantly different from those in the control group. Our findings suggest that in patients with NIDDM, the regulation of IGFBP-1 is markedly influenced by the choice of treatment.

The phosphorylation pattern of insulin-like growth factor-binding protein-1 in normal plasma is different from that in amniotic fluid and changes during pregnancy

We have determined the phosphorylation pattern of circulating insulin-like growth factor-binding protein-1 (IGFBP-1) in normal subjects and assessed how this changes in pregnancy. Two RIAs employing different monoclonal antibodies (MAbs 6303 or 6305) were used to measure IGFBP-1. In normal subjects, RIA 6303 measured 11-fold higher levels than RIA 6305 (72.8 vs. 6.6 micrograms/L; P < 0.008). However, in amniotic fluid (AF), the two assays gave similar results. Immunoprecipitation of plasma and AF with MAb 6303 and 6305 before nonsodium dodecyl sulfate-electrophoresis and Western ligand blotting revealed different IGFBP-1 isoforms and differential antibody recognition as the cause of this discrepancy. In AF, both MAbs precipitated nonphosphorylated and phosphorylated isoforms, whereas in plasma, only a single highly phosphorylated species, not seen in AF, was observed. This form of IGFBP-1 was precipitated by MAb 6303 only. During pregnancy, the phosphorylation state of IGFBP-1 in the maternal circulation was altered, as nonphosphorylated IGFBP-1 and three lesser phosphoforms were also observed. The appearance of these other variants resulted in a significant increase in IGFBP-1 measured by RIA 6305 (37, 51, and 83 micrograms/L in first, second, and third trimesters, respectively; P < 0.0005 vs. controls). The changes in IGFBP-1 phosphorylation induced by pregnancy may influence the modulatory effects of IGFBP-1 on IGF bioavailability and, hence, fetal growth.

Measurement of insulin-like growth factor-II in human plasma using a specific monoclonal antibody-based two-site immunoradiometric assay

An immunoradiometric assay (IRMA) for the measurement of insulin-like growth factor-II (IGF-II) in human plasma has been developed, optimized and evaluated clinically in normal subjects and patients with disorders of the GH/IGF-I axis. Six monoclonal antibodies (MAbs) to recombinant human IGF-II (rhIGF-II) were produced, all of which had low cross-reactivity with rhIGF-I (< 0.01%) and insulin (< 0.01%). Compatibility of pairs of MAbs was tested in two-site IRMAs using three radioiodinated MAbs and three MAbs linked to Sephacryl S-300 (with separation of bound and free radiolabelled MAb by sucrose layering). Seven pairs of MAbs bound rhIGF-II and the combination of 125I-labelled W3D9 and W2H1 linked to solid phase was selected. The optimized assay had a completion time of 4 h, a minimum detection limit of 30 ng/ml (2.5 standard deviations from the zero standard) and detected a single peak of endogenous IGF-II in normal plasma which co-eluted with rhIGF-II after acid gel chromatography. IGF-II was measured in formic acid/acetone extracts of plasma from 16 normal subjects (mean 685, range 516-1008 micrograms/l), four acromegalic patients (mean 637, range 553-700 micrograms/l), fourteen patients with type-1 diabetes (mean 635, range 247-753 micrograms/l), nine patients with uraemia (mean 423, range 78-850 micrograms/l), and three patients with Laron-type GH insensitivity (75, 35 and 36 micrograms/l). No significant fluctuations were detected between samples obtained hourly from 08.00 to 19.00 h in normal subjects. Low levels of IGF-binding proteins (IGFBPs) remaining in plasma extracts may interfere with the measurement of IGF-II and give rise to falsely elevated IGF-II levels in radioimmunoassays or falsely suppressed levels in IRMAs. Such interference did not occur with the IRMA when used to measure IGF-II in extracts from normal subjects, acromegalic patients and patients with type-1 diabetes, and the addition of excess rhIGF-I in order to displace IGF-II from residual IGFBPs had no effect on IGF-II measurements in these samples. However, levels of IGF-II measured in extracts from patients with Laron-type GH insensitivity and patients with uraemia increased markedly after preincubation with excess rhIGF-I. The accurate measurement of IGF-II by IRMA in extracts from these subjects therefore requires the displacement of IGF-II from IGFBPs prior to assay. We conclude that, in contrast to radioimmunoassays, the two-site IRMA developed here provides a practical, rapid and specific method for the measurement of IGF-II in human plasma.

Growth and development of full-term nonasphyxiated small-for-gestational-age newborns: follow-up through adolescence

Previous studies of growth and development in small-for-gestational-age (SGA) infants have been plagued by several methodologic defects, including a lack of control for socioeconomic status and parental height and an inability to distinguish among the effects of prematurity, neonatal asphyxia, and intrauterine growth retardation. An attempt has been made to overcome these defects in a study of 33 full-term, nonasphyxiated small-for-gestational-age neonates born between 1960 and 1966 and 33 matched control infants of normal birth weight. The infants were followed up and compared for physical growth and sexual, neurologic, and cognitive development at ages 13 to 19 years. Significant deficits in height, weight, and head circumference were found among the SGA cohort, even after statistical adjustment for differences in socioeconomic status and parental height. Sexual development and bone age were not delayed in the SGA group, however, indicating that the deficits in growth are permanent. On neurologic and cognitive testing, the SGA group had trends toward lower scores but scores were well within the normal range. It is concluded that full-term nonasphyxiated SGA infants have an impaired potential for physical growth, but a good prognosis for neurologic and cognitive development. Previous findings of more severe cognitive deficits are attributed to a failure to distinguish the effects of isolated intrauterine growth retardation from effects due to asphyxia.

Serum gamma-glutamyl transpeptidase acitvity: a chemical determinant of alcohol consumption during adolescence

The drinking habits of 55 adolescents, aged 12 to 22 years, were evaluated in light of the current presumed upsurge in adolescent alcohol use. SGPT, SGOT, and alkaline phosphatase concentrations were essentially normal in all subjects. Serum gamma-glutamyl transpeptidase (GGTP) concentrations were elevated in 12 of 15 adolescents who consumed six or more drinks per day. It is suggested that this test may warrant inclusion among other targeted screening procedures performed in teenage patients suspected of heavy alcohol consumption.

Endocardial fibroelastosis and Niemann-Pick disease

The concurrence of endocardial fibroelastosis and Niemann-Pick disease is described. This appears to be the first described case of endocardial fibroelastosis in association with a lipid storage disorder.

Heredity in primary endocardial fibroelastosis

Twenty-six cases of endocardial fibroelastosis were collected from three hospitals in Manchester over a ten-year period. Nine cases occurred in 4 families and these are discussed in detail. X-linked recessive inheritance seems likely in one family in which two probable female carriers had subarachnoid haemorrhages. In a second family an apparently normal man produced two children with endocardial fibroelastosis by different mothers suggesting autosomal dominant inheritance with incomplete penetrance. Autosomal recessive inheritance may be involved in the remaining two families but this was not associated with consanguinity. Genetic heterogeneity is evident in endocardial fibroelastosis and the majority of cases occur sporadically. An accurate family history is therefore necessary but it is difficult to give precise recurrence risks in sporadic cases.

Response to influenza vaccine in adjuvant 65-4

A comparison was made of the antibody response and subjective reactions to zonally-purified influenza vaccine in aqueous suspension and in peanut oil adjuvant 65-4. Both preparations contained 700 CCA units of A/Aichi/2/68, and 300 CCA units of B/Mass/1/71. Subjective reactions were recorded by asking the volunteers to complete a record daily for 5 days. Pain at the injection site was recorded by 64 per cent of the recipients of the oil adjuvant vaccine compared with 35 per cent of the aqueous recipients, but local redness was more frequent after aqueous vaccine. Systemic symptoms was recorded a little more frequently after aqueous than oil adjuvant vaccine. When measured 71/2 weeks after a single dose of vaccine, the HAI geometric mean antibody titre (G.M.T) to the A/Hong Kong/1/68 antigen (antigenically similar to the A/Aichi/2/68 antigen in the vaccine) increased 2-7 fold after aqueous and 16-4 fold after adjuvant vaccine. Sixty-two weeks after vaccination the antibody titres remained higher in those given adjuvant vaccine. The G.M.T. to B/Mass/1/71 increased 1-9 fold 71/2 weeks after aqueous vaccine and 3-7 fold after adjuvant vaccine. The antibody response to both influenza A and B antigens was broader in the recipients of adjuvant vaccine. The G.M.T. to A/England/42/72 increased 2-8-fold after aqueous and 13-fold after adjuvant vaccine; and to B/England/847/73 it increased 1-3-fold after aqueous and 1-9-fold after adjuvant vaccine.

A method of comparing differences in tumour growth rates applied to a study of the increasing growth capacity of mouse carcinomata

A method of comparing differences in growth rates of tumours in small groups of animals is described. A common slope can be fitted to the growth curves of a given tumour in a group of isogeneic animals. Differences between growth potentials can be demonstrated by comparing the common slope for a given tumour against that of another tumour (or the same tumour at a later stage of development).A highly significant difference is shown between the growth potential of an A-strain mammary carcinoma after 7 or after 28 days' growth in isogeneic animals. Since this increase in autonomy is reflected in the tumour's subsequent growth rate in secondary hosts, it is suggested that it involves adaptation of the tumour rather than progressive immunodepression of the primary host.

The British reference preparation for influenza virus haemagglutinin

The two methods for measuring the haemagglutinin content of an influenza virus suspension are the haemagglutinating (HA) and chick cell agglutinating (CCA) techniques and both measure the same biological activity. With the establishment of an international reference preparation for influenza virus haemagglutinin (type A), however, it seems logical to express the haemagglutinin content of influenza vaccines in international units. Accordingly a collaborative study was arranged in order to obtain agreement on the number of units to be assigned to a British reference preparation for influenza haemagglutinin. It was agreed that the preparation contains 190 i.u. per ampoule and 1 i.u. is contained in 0.0622 mg. of the dried material.