Construction of a novel expression cassette for increasing transgene expression in vivo in endothelial cells of large blood vessels.

The success of gene therapy hinges on achievement of adequate transgene expression. To ensure high transgene expression, many gene-therapy vectors include highly active virus-derived transcriptional elements. Other vectors include tissue-specific eukaryotic transcriptional elements, intended to limit transgene expression to specific cell types, avoid toxicity and prevent immune responses. Unfortunately, tissue specificity is often accompanied by lower transgene expression. Here, we use eukaryotic (murine) transcriptional elements and a virus-derived posttranscriptional element to build cassettes designed to express a potentially therapeutic gene (interleukin (IL)-10) in large-vessel endothelial cells (ECs) at levels as high as obtained with the cytomegalovirus (CMV) immediate early promoter, while retaining EC specificity. The cassettes were tested by incorporation into helper-dependent adenoviral vectors, and transduction into bovine aortic EC in vitro and rabbit carotid EC in vivo. The murine endothelin-1 promoter showed EC specificity, but expressed only 3% as much IL-10 mRNA as CMV. Inclusion of precisely four copies of an EC-specific enhancer and a posttranscriptional regulatory element increased IL-10 expression to a level at or above the CMV promoter in vivo, while retaining--and possibly enhancing--EC specificity, as measured in vitro. The cassette reported here will likely be useful for maximizing transgene expression in large-vessel EC, while minimizing systemic effects.

Birth weight discordance of twin pairs and their subsequent growth patterns.

BACKGROUND: Few studies have compared the growth of a twin with its co-twin and particularly in relation to birth weight discordance. AIM: The study investigated how the degree of birth weight discordance affected subsequent growth. METHODS: Birth weight discordance of 762 twin pairs was determined. Subsequent weight, height and occipital-frontal head circumference (OFC) measurements were obtained between the ages of 2-9 years. Corresponding standard deviations scores (SDS) were analysed according to birth weight discordance, sex and zygosity. Weight status was taken into account by assigning twins into sub-groups according to whether they were the heavier twin at birth and remained heavier, became the lighter of the twin pair or had the same weight, for subsequent measurements. RESULTS AND CONCLUSIONS: The degree of birth weight discordance had little effect on subsequent growth except in monozygotic (MZ) twins with >20% discordance. Severe low birth weight ( < 1.95 kg) is more significant in suppressing subsequent growth than the degree of discordance per se. A surprisingly high proportion of twins reversed their weight status when reviewed at an older age.

A comparison of the merits of using birth weight, or appropriateness of birth weight to gestational age, in the assessment of subsequent growth in twin children.

BACKGROUND: Size at birth has an important relationship to subsequent growth. Many reports subgroup subjects according to birth weight or birth weight in relation to the duration of gestation, and it is not clear whether one of these methods is more relevant to subsequent growth or if in fact they are comparable. AIM: The present study compared the outcome of twins in terms of pre-pubertal weight and height when sub-grouped according to birth weight (BW), or the appropriateness of birth weight for the duration of gestation (BW-SDS). SUBJECTS AND METHODS: The birth weights of 1533 twins were graded into four subgroups according to BW or BW-SDS. The relationship of birth weight to subsequent weight and height standard deviation scores, obtained between the ages of 2 and 9 years, were compared on the basis of these two methods. RESULTS: There was a marked difference in identity of the twins who fell into each of the four subgroups by the two methods. Despite this, no difference was found in the subsequent weight and height of the twins. CONCLUSIONS: Analysis of data relating BW-SDS to subsequent growth shows no significant difference to those groups using BW alone.

Biochemical tests in the diagnosis of childhood growth hormone deficiency.

GH stimulation tests are widely used in the diagnosis of GH deficiency (GHD), although they are associated with a high false positive rate. We have examined, therefore, the performance of other tests of the GH axis [urinary GH excretion, serum insulin-like growth factor I(IGF-I), and IGF-binding protein-3 (IGFBP-3) levels] compared with GH stimulation tests in identifying children defined clinically as GH deficient. Group I comprised 60 children (mean age, 10.3 +/- 4.8 yr) whose diagnosis of GHD was based on a medical history indicative of pituitary dysfunction (n = 43) or on the typical phenotypic features and appropriate auxological characteristics of isolated GHD (n = 17). Group II comprised 110 short children (mean age, 9.8 +/- 4 yr) in whom GHD was not suspected, but needed exclusion. The best sensitivity for a single GH test was 85% at a peak GH cut-off level of 10 ng/mL, whereas the best specificity was 92% at 5 ng/mL. The sensitivities of IGF-I, IGFBP-3, and urinary GH, using a cut-off of -2 SD score were poor at 34%, 22%, and 25%, respectively, with specificities of 72%, 92%, and 76% respectively. Only 2 of 21 pubertal children in group I and none of the 27 subjects with radiation-induced GHD had an IGFBP-3 SD score less than -1.5. We devised a scoring system based on the positive predictive value of each test, incorporating data from the GH test and the IGF-I and IGFBP-3 levels. A specificity of 94% could be achieved with a score of 10 or more (maximum 17) (sensitivity 34%). The latter could not be improved above 81% with a score of 5 points or more (specificity, 69%). A high score was, therefore, highly indicative of GHD, but was achieved by few patients. A normal IGFBP-3 level, however, did not exclude GHD, particularly in patients with radiation-induced GHD and those in puberty. A GH test with a peak level more than 10 ng/mL was the most useful single investigation to exclude a diagnosis of GHD.

A limited repertoire of mutations of the luteinizing hormone (LH) receptor gene in familial and sporadic patients with male LH-independent precocious puberty.

Herein, we report mutation analysis of the LH receptor gene in 17 males with LH-independent precocious puberty, of which 8 were familial and 9 had a negative family history. A total of 7 different mutations (all previously reported) were detected in 12 patients. Among 10 European familial male-limited precocious puberty (FMPP) patients who had a LH receptor gene mutation, none had the Asp578Gly mutation, which is responsible for the vast majority of cases in the U.S. The restricted number of activating mutations of the LH receptor observed in this and other studies of FMPP strongly suggests that an activating phenotype is associated with very specific sites in the receptor protein. Clinical follow-up of the 5 patients who did not have LH receptor mutations shows that such cases most likely do not have true FMPP. LH receptor mutation analysis provides a sensitive tool for distinguishing true FMPP from other causes of early-onset LH-independent puberty in males.

Priming with testosterone enhances stimulated growth hormone secretion in boys with delayed puberty.

BACKGROUND AND OBJECTIVE: Tests for growth hormone (GH) deficiency are not always helpful in the differential diagnosis of physiological delay of growth and puberty and GH deficiency. PATIENTS AND METHODS: To enhance diagnostic specificity, we used a single dose testosterone priming before repeating the arginine stimulation test in 26 boys with short stature and only early signs of puberty who failed to show an adequate response of serum GH in the first test. RESULTS: 77% (20/26 patients) increased their serum GH peak to more than 10 ng/ml, whereas six patients were still below this concentration. CONCLUSION: We propose that testosterone priming is a useful tool to distinguish between physiological delay of growth and puberty and GH deficiency and should be included in the diagnostic procedure.

The growth of twins between the ages of 2 and 9 years.

BACKGROUND: Twin growth studies are mostly based on pooled data without consideration of zygosity, parental heights or birth weight. AIM: The study investigated the effects of gender, zygosity, parental height and birth weight on subsequent twin growth. METHODS: Height and weight measurements of 1533 twins (n = 1077 for occipito-frontal head circumference (OFC)), age range 2-9 years, were converted to standard deviation scores derived from singleton standards. Their growth was evaluated in relation to gender, zygosity, parental heights and birth weight. RESULTS: Mean stature of twins fell only slightly below the reference values of singletons, but they were underweight to a greater extent (boys more than girls). Twins' OFC were low (girls more so than boys). Monozygotic (MZ) twin boys were lighter and shorter than dizygotic twins and MZ twin girls. Deficient growth was most evident in those babies light at birth. Parental heights only partly accounted for the difference in height of twins. CONCLUSIONS: Birth weight and parental height are important in relation to subsequent growth. Boy twins are at a disadvantage compared with girls in terms of their growth in height and weight, particularly in the low birth weight and MZ groups.

Growth characteristics in twins and higher order multiple births.

Measurements of height and weight have been undertaken on 201 pairs of twins and 46 sets of higher multiples once each at various ages through childhood. The heights of twins are comparable to the overall population of singletons, those of higher multiples are slightly undersized. However, the total group of twins were shorter than expected when compared with the heights of parents and siblings, but this was entirely accounted for by that component of the group who at birth had been very light for dates. The children in all groups of multiples were underweight for their height in comparison with standards of a comparable population and with their own siblings.

Skeletal age changes in puberty.

Changes in skeletal age and height of 34 Leeds schoolboys were studied in a four year longitudinal survey covering puberty. Tanner and Whitehouse method TW2 was used. In each boy, skeletal age advanced rapidly during puberty, reaching a peak at an age related to that of peak height velocity. The importance of recognising that this acceleration of bone age is normal is stressed, in order to avoid attributing it to other causes.

Are Tanner growth charts applicable to children at school entry in Leeds?

Analysis of the heights and weights of about 85% of school entrants in Leeds in 1982 and 1983 showed that the distribution at a mean of 5.3 years is similar to the accepted standard centiles and confirms the appropriateness of the use of these standards at this age.

Leptospirosis presenting with erythema nodosum.

An illness due to a leptospiral infection in a boy aged 12 years is described which, in addition to presenting with severe fever, malaise, and aseptic meningitis, showed the rare features of severe bradycardia and erythema nodosum.

Birth weight and head circumference standards for English twins.

This study was undertaken to provide reliable up to date information on birth weights and occipitofrontal head circumference measurements in relation to gestational age for English newborn twins. Records from 36 maternity units in England, mainly from 1988-92, have provided data on birth weights for over 19,000 newborn twins with gestational ages ranging from 23 to 41 weeks, and on head circumference measurements for over 5300 twins ranging from 28 weeks to 40 weeks' gestation. Centile charts have been produced for boy and girl twins showing the distribution of these values against gestational age. The findings confirm the greater weights of boys compared with girls throughout, increasing from a mean of about 50 g at early stages to 100 g later, in a similar way to that reported for singletons. Twins were lighter than comparable singletons by about 100 g at 24 weeks, increasing progressively to 4-500 g at 38 weeks' gestation. In contrast, differences in occipitofrontal head circumferences between singletons and twins were only evident with gestations longer than 35 weeks--and from 37 weeks' gestation onwards the mean head circumference of singletons exceeded that of twins by about 5 mm. It is recommended that in evaluating the significance of the birth weight of a twin in relation to gestation, twin standards such as the ones presented here should be used rather than those relating to singletons.

Longitudinal study of height and weight at adolescence.

A longitudinal study through puberty of the height and weight of 96 boys and 102 girls in schools in and around the city of Leeds was conducted. Data for height and weight and height and weight velocities are presented, which are based on chronological age and on age relative to the age of peak height velocity. Comparison was made with the Tanner standards: male puberty developed a little later but growth continued longer, so that the adult men were taller and heavier. Girls showed a similar timing of puberty to the Tanner standards but were lighter at all ages and ultimately slightly taller as growth was not completed until later. It is important to know the pubertal state when interpreting growth changes in children.