Biochemical, molecular and preclinical characterization of a double-virus-reduced human butyrylcholinesterase preparation designed for clinical use.

BACKGROUND AND OBJECTIVES: A human plasma-derived butyrylcholinesterase preparation manufactured on the industrial scale is described. MATERIAL AND METHODS: The human butyrylcholinesterase (hBChE) product was extensively investigated for its purity using immunological and electrophoretic methods and characterized by thorough glycoproteomic approaches. A comprehensive preclinical testing programme addressing safety and pharmacokinetic parameters supplemented the biochemical characterization. RESULTS: The high-purity hBChE preparation is tetrameric and has high specific activity and molecular integrity of the protein backbone. Acute toxicity studies and in vivo thrombogenicity studies provided evidence of a sufficient safety margin for use in humans. CONCLUSION: Extensive preclinical safety and pharmacokinetic testing confirmed that this hBChE preparation can be used for further efficacy testing as a bioscavenger for toxic organophosphate compounds in appropriate animal models and ultimately in humans.

Modulation of factor VIII-specific memory B cells.

The development of inhibitory antibodies against factor VIII (FVIII) is the major complication in patients with haemophilia A who are treated with FVIII products. Memory B cells play an essential role in maintaining established antibody responses. Upon re-exposure to the same antigen, they are rapidly re-stimulated to proliferate and differentiate into antibody-secreting plasma cells (ASC) that secrete high-affinity antibodies. It is, therefore, reasonable to believe that memory B cells have to be eradicated or inactivated for immune tolerance induction therapy to be successful in patients with haemophilia A and FVIII inhibitors. The aim of our studies was the development of strategies to prevent FVIII-specific memory B cells from becoming re-stimulated. We established a 6-day in vitro culture system that enabled us to study the regulation of FVIII-specific murine memory-B-cell re-stimulation. We tested the impact of the blockade of co-stimulatory interactions, of different concentrations of FVIII and of ligands for toll-like receptors (TLR). The blockade of B7-CD28 and CD40-CD40 ligand interactions prevented FVIII-specific murine memory B cells from becoming re-stimulated by FVIII in vitro and in vivo. Furthermore, high concentrations of FVIII blocked re-stimulation of FVIII-specific murine memory B cells. Triggering of TLR7 amplified re-stimulation by low concentrations of FVIII and prevented blockade by high concentrations of FVIII. We conclude that we defined modulators that either amplify or inhibit the re-stimulation of FVIII-specific murine memory B cells. Currently, we are investigating whether the same modulators operate in patients with haemophilia A and FVIII inhibitors.

Effects of growth hormone treatment in juvenile idiopathic arthritis: bone and body composition.

BACKGROUND: Inflammation and glucocorticoid therapy are major factors influencing growth and bone maturation in patients with juvenile idiopathic arthritis (JIA). In addition to alterations in total bone mineral density and bone geometry, longitudinal data confirm that the main contributors to errant bone maturation in patients with JIA are reductions in muscle mass and force. Growth hormone (GH) therapy, which has shown efficacy in controlling disease, may also positively influence body composition. For several years, GH therapy has been used to treat growth retardation in patients with JIA receiving glucocorticoids. GH therapy normalizes growth velocity, increases height, bone mineral density and bone mass and changes bone geometry. Despite ongoing glucocorticoid therapy, muscle mass and bone size substantially increase with GH therapy. Increased bone size suggests improved bone stability, which may reduce fracture risk. Along with the increase in muscle mass, patients experience stabilized or slightly decreased fat mass during GH therapy. CONCLUSIONS: All these effects suggest an anabolic effect of GH therapy on bone and body composition.

Development of a plasma- and albumin-free recombinant von Willebrand factor.

Baxter has developed a recombinant therapy for treating von Willebrand's disease. Recombinant VWF is co-expressed with the rFVIII in CHO cells used to produce the rFVIII product Advate. This rVWF is used as a drug component for a rVWF-rFVIII complex drug product. CHO cells produce partially processed and partially un-processed rVWF still containing the pro-peptide. In order to make a consistent preparation containing mature and processed rVWF only rVWF is exposed to recombinant furin to remove the pro-peptide. Recombinant VWF and furin are produced under serum- and protein-free conditions. It is highly purified by a series of chromatographic steps and formulated in a protein-free buffer and has a homogeneous multimer distribution. The specific activity is higher in rVWF than in commercial plasma-derived VWF-FVIII complex products. SDS agarose electrophoretic analysis shows the presence of ultra-high molecular weight multimers. The FVIII-binding capacity and affinity of rVWF to FVIII is comparable to VWF in plasma. Carbohydrate analysis shows an intact glycosylation pattern. Recombinant VWF binds to collagen and promotes platelet adhesion under shear stress. It stabilizes endogenous FVIII in VWF-deficient knock-out mice as seen by a secondary rise in murine FVIII.

A new liquid intravenous immunoglobulin with three dedicated virus reduction steps: virus and prion reduction capacity.

BACKGROUND AND OBJECTIVES: A new 10% liquid human intravenous immunoglobulin (US trade name: Gammagard Liquid; European trade name: KIOVIG) manufactured by a process with three dedicated pathogen inactivation/removal steps (solvent/detergent treatment, 35-nm nanofiltration and low pH/elevated temperature incubation) was developed. The ability of the manufacturing process to inactivate/remove viruses and prions was investigated. MATERIALS AND METHODS: Virus and prion removal capacities were assessed with down-scale spiking experiments, validated for equivalence to the large-scale process. RESULTS: Lipid-enveloped viruses were completely inactivated/removed by each of the three dedicated virus clearance steps, and for human immunodeficiency virus 1 (HIV-1) and pseudorabies virus (PRV), also by the upstream cold ethanol fractionation step. Relevant non-enveloped viruses [i.e. hepatitis A virus (HAV) and parvovirus B19 (B19V)] were effectively removed by nanofiltration and the cold ethanol fractionation step, and partial inactivation of non-enveloped viruses was achieved by low pH incubation. Overall log reduction factors were > 20.0 for HIV-1, > 18.1 for bovine viral diarrhoea virus, > 16.3 for West Nile virus, > 10.0 for influenza A virus subtype H5N1, > 21.8 for PRV, 12.0 for HAV, > 12.1 for encephalomyocarditis virus, 10.6 for B19V and 10.3 for mice minute virus. Prions (Western blot assay) were completely removed (> or = 3.2 mean log reduction) by a step of the cold ethanol fractionation process. CONCLUSIONS: Introducing three dedicated virus-clearance steps in the manufacturing process of immunoglobulins from human plasma provides high margins of safety.

Variation of anti-Fas antibodies in different lots of intravenous immunoglobulin.

BACKGROUND AND OBJECTIVES: Previous studies have presented evidence that human immunoglobulin G preparations for intravenous use contain antibodies directed against the death receptor Fas (CD95). The function of these antibodies was described as either antagonistic or agonistic; therefore, inhibiting or stimulating Fas-dependent apoptosis. Based on these reports, we asked whether the proportion of antagonistic and agonistic anti-Fas activities differs between different lots of intravenous immunoglobulin (IVIG). Variations between lots would open the possibility to preselect suitable lots of IVIG for different therapeutic purposes. MATERIALS AND METHODS: Eleven lots of IVIG were tested for their ability to induce or inhibit Fas-dependent apoptosis. The biological significance of anti-Fas antibodies was confirmed by including anti-Fas antibodies purified from IVIG and IVIG depleted of anti-Fas antibodies in the study. RESULTS: All 11 lots inhibited FasL-induced apoptosis. In addition, five lots stimulated apoptosis in the absence of FasL. Depletion of anti-Fas antibodies from IVIG abolished the capacity of IVIG to inhibit FasL-induced apoptosis, but reduced the ability to induce apoptosis only slightly. CONCLUSION: The inhibition of FasL-induced apoptosis by IVIG is because of the presence of antagonistic anti-Fas antibodies. The activity of these antibodies differs considerably between different lots. On the other hand, the induction of apoptosis by IVIG is probably because of the concerted action of a range of different antibodies. The variation in the proportion of stimulating and inhibiting anti-Fas activities between different lots of IVIG opens the possibility to preselect suitable lots for different therapeutic purposes.

Successful early dietary intervention avoids obesity in patients with Prader-Willi syndrome: a ten-year follow-up.

UNLABELLED: Hyperphagia is a frequent symptom in patients with Prader-Willi syndrome (PWS) and results in marked obesity with the risk of metabolic and cardiovascular complications. AIM: To investigate whether early diagnosis of PWS and strict dietary intervention prevents excessive weight gain in patients with PWS. PATIENTS AND METHODS: A strict fat reduced and modified carbohydrate diet consisting of 10 kcal/ cm height was provided to nine patients (seven female, two male) diagnosed early with PWS (group A). Patients were prospectively followed at our center with follow-up visits every three months. Eight patients with late diagnosis of PWS served as controls (group B). Body mass index (BMI) SDS and height SDS were compared between these two groups over a ten-year period. RESULTS: At the age of two years height SDS and BMI SDS were significantly lower in group A (-2.9 vs -1.2, p <0.05, and BMI SDS -0.1 vs +1.8, p < 0.05). After ten years BMI SDS increased significantly to +1.2 SDS in group A, but was still significantly lower than in group B (BMI SDS +2.4), p <0.005. Patients without restrictive diet were significantly taller than patients on the diet (height SDS group A -2.8 vs group B -1.3, p < 0.05). CONCLUSION: Early dietary treatment starting at the second year of life and continued until the age of ten years is effective in avoiding excessive weight gain in patients with PWS, but results in shorter stature. Therefore growth hormone may be a useful additional treatment in these patients.

Activated human protein C prevents thrombin-induced thromboembolism in mice. Evidence that activated protein c reduces intravascular fibrin accumulation through the inhibition of additional thrombin generation.

Activated protein C (APC) is a potent physiologic anticoagulant with profibrinolytic properties, and has been shown to prevent thrombosis in different experimental models. We investigated the effect of human APC on thrombin-induced thromboembolism in mice, a model of acute intravascular fibrin deposition leading to death within minutes. APC given intravenously (i.v.) as a bolus 2 min before thrombin challenge (1,250 U/kg) reduced mortality in a dose-dependent manner despite the lack of thrombin inhibitor activity. Significant inhibition of thrombin-induced death was observed at the dose of 0.05 mg/kg, and maximal protection was obtained with 2 mg/kg (> 85% reduction in mortality rate). Histology of lung tissue revealed that APC treatment (2 mg/kg) reduced significantly vascular occlusion rate (from 89.2 to 46.6%, P < 0.01). The protective effect of APC was due to the inhibition of endogenous thrombin formation as indicated by the fact that (a) the injection of human thrombin caused a marked decrease in the coagulation factors of the intrinsic and common pathways (but not of Factor VII), suggesting the activation of blood clotting via the contact system; (b) APC pretreatment reduced markedly prothrombin consumption; (c) the lethal effect of thrombin was almost abolished when the animals were made deficient in vitamin K-dependent factors by warfarin treatment, and could be restored only by doubling the dose of thrombin, indicating that the generation of endogenous thrombin contributes significantly to death; and (d) APC failed to protect warfarin-treated animals, in which mortality is entirely due to injected thrombin, even after protein S supplementation. Other results suggest that APC protects from thrombin-induced thromboembolism by rendering the formed fibrin more susceptible to plasmin degradation rather than by reducing fibrin formation: in thrombin-treated mice, fibrinogen consumption was not inhibited by APC; and inhibition of endogenous fibrinolysis by epsilon-aminocaproic or tranexamic acid resulted in a significant reduction of the protective effect of APC. Since APC did not enhance plasma fibrinolytic activity, as assessed by the measurement of plasminogen activator (PA) or PA inhibitor (PAI) activities, PAI-1 antigen, or 125I-fibrin degrading activity, we speculate that the inhibition of additional (endogenous) thrombin formation by APC interrupts thrombin-dependent mechanisms that make fibrin clots more resistant to lysis, so that the intravascular deposited fibrin can be removed more rapidly by the endogenous fibrinolytic system.

Young adults born small for gestational age: is reduced baroreceptor sensitivity a risk factor for hypertension?

UNLABELLED: BACKGROUND. Adults born small for gestational age (SGA) are at increased risk for the metabolic syndrome and cardiovascular disease. HYPOTHESIS: Impaired short-term blood pressure regulation may contribute to the development of hypertension in patients born SGA. METHODS: In all, 43 patients born SGA (18 female, age 19.4 +/- 0.3 years) were evaluated by beat-to-beat blood pressure and heart rate registration during rest and mental and orthostatic stress. The study group was divided into Group 1 with normal resting blood pressure (n=32) and Group 2 with slightly elevated blood pressure (n=11). Baroreceptor sensitivity (BRS) was calculated. Fasting insulin as well as lipid levels were correlated with hemodynamic parameters. RESULTS: Eleven of the 43 study patients (25%) had a slightly elevated resting systolic blood pressure (SBP) rising during mental and orthostatic stress. Body mass index (BMI) and fasting insulin levels correlated strongly with SBP in Group 2. Baroreceptor sensitivity was lower in Group 2 at rest (p < 0.05). CONCLUSIONS: Three components of metabolic syndrome (elevated BP, high BMI, elevated insulin levels) correlate strongly in young adolescents born SGA; BRS is reduced in prehypertensive patients. Close follow-up is warranted during adult life as they are predisposed for developing a metabolic syndrome with elevated cardiovascular risk.

Pubertal height gain in Ullrich-Turner syndrome.

Short stature and ovarian failure are the main features in Ullrich-Turner syndrome (UTS). The aim of this retrospective analysis was to evaluate the influence of age at initiation of puberty on final height. Sixty-five girls were treated with growth hormone (GH) and had a final height of 150.6 +/- 5.7 cm; 12/65 entered puberty spontaneously. A non-GH treated group of 12 girls with UTS reached a final height of 147.3 +/- 6.6 cm. Subdividing the GH treated group (n = 53) based on the age at induction of puberty, before or after 13 years, there was no significant difference in final height. Final height was affected by the age at which GH treatment was initiated, height SDS at the beginning of puberty, and by the duration of GH therapy. Therefore, early treatment with GH for short stature in UTS should be attempted so that an age adequate initiation of puberty will be feasible.

Growth hormone changes bone geometry and body composition in patients with juvenile idiopathic arthritis requiring glucocorticoid treatment: a controlled study using peripheral quantitative computed tomography.

Osteopenia and growth retardation have been described in children with chronic arthritis. GH has an impact on both. In the present controlled study, we used peripheral quantitative computed tomography to evaluate forearm bone mass, density, and geometry as well as forearm muscle and fat area in 17 patients with juvenile idiopathic arthritis (JIA) receiving treatment with GH for 3.8 +/- 1.1 yr compared with an untreated age- and sex-matched control group (n = 17). All patients had a mean age of 15.3 +/- 2.5 yr and a mean duration of illness of 8.2 +/- 4.4 yr. Height, weight, body mass index, bone parameters, and muscle area were significantly decreased in both groups compared with those in healthy age-matched children. Compared with untreated JIA patients, GH-treated JIA patients had significant higher bone mineral content as well as total cross-sectional area (CSA), cortical CSA, and muscle CSA. Fat CSA was lower in the GH-treated group. A significant difference between groups for height-corrected cortical and muscle areas was only seen in male patients. Cortical CSA relative to muscle CSA was not different between groups. These findings are compatible with an anabolic effect of GH on muscle and bone development.

CYP21 mutations in simple virilizing congenital adrenal hyperplasia.

We studied the functional and structural effects of two unique missense mutations in CYP21 found in patients with simple virilizing congenital adrenal hyperplasia. The rare variants L300F and V281G were found in two girls who were each hemizygous for one of the mutations. Functional analysis after expression in COS-1 cells revealed that the mutant enzymes had reduced enzymatic activity for conversion of both 17-hydroxyprogesterone (L300F 9.5%, V281G 3.9% of normal) and progesterone (L300F 4.4%, V281G 3.9% of normal). Both mutant enzymes had an increased degradation in mammalian COS-1 cells compared to the normal protein, although the L300F variant affected the degradation pattern to a greater extent. Our data indicate that the residue L300 is important in maintaining normal structure of the 21-hydroxylase enzyme whereas mutations affecting V281 most likely cause impaired enzyme activity by interfering with a specific function(s) of the protein.

An update on clinical and basic aspects of the protein C anticoagulant pathway.

The protein C anticoagulant pathway provides a mechanism for regulating the coagulation process through the selective inactivation of factors Va and VIIIa. Recent studies have suggested that factor V may facilitate this process and that a mutation at one of the inactivation sites can contribute to resistance to activated protein C (APC) inactivation of factor Va. This appears to be a common cause of familial thrombophilia. The control mechanisms involved in factor Va inactivation have also begun to become more clear. Membrane surfaces seem to be critical to complete factor Va inactivation, and the membrane composition requirements for optimal anticoagulant activity are distinct from those of procoagulant reactions. Specifically, the APC anticoagulant activity requires phosphatidylethanolamine, whereas the prothrombin activation complex does not. These observations may partially explain thrombotic complications with antiphospholipid antibodies in which the some antibodies have been shown to react preferentially with phosphatidylethanolamine and could, therefore, selectively block APC function. Clinically, more complete studies on partial protein C deficiency indicate that, at least within families, the deficiency is a significant risk factor for thrombosis. The impact of deficiencies on thrombotic risk suggests that protein C or other components of the pathway may be useful therapeutic agents. The limited clinical experience in treating meningococcemia, warfarin-induced skin necrosis, and homozygous protein C deficiency with protein C concentrates suggests that this approach is safe and effective.

Bromocriptine treatment in adolescent boys with familial tall stature: a pair-matched controlled study.

Recently, bromocriptine has been proposed as a novel agent for the treatment of excessively tall stature in adolescents. To further test its value, we treated nine boys, aged 10.0-15.4 yr, for 1 yr with bromocriptine (7.5 mg/day). A paradoxical plasma GH response to TRH was demonstrated in four of eight boys before and in five boys after 6 months of bromocriptine treatment. At the onset of therapy, the mean adult height prediction was 202.2 +/- 4.3 (+/- SD) cm (Bayley-Pinneau), 202.1 +/- 4.7 cm (TW Mark II), and 198.6 +/- 5.3 cm (Roche-Wainer-Thissen). After 1 yr of therapy, the mean adult height prediction had changed by -4.5 +/- 2.6 cm (Bayley-Pinneau), -3.4 +/- 2.2 cm (TW Mark II), and -2.6 +/- 1.2 cm (Roche-Wainer-Thissen). These reductions were solely due to a decrease in growth velocity and not to an increased skeletal maturation rate. To substantiate these findings, each treated boy was pair-matched with an untreated tall boy so that their chronological and skeletal ages differed by less than 1 yr. After 1 yr of follow-up, height predictions in the treated boys compared with those in the matched control boys gave significantly reduced results with the Bayley-Pinneau and the Roche-Wainer-Thissen, but not with the TW Mark II, method. Because of this discrepancy it is uncertain whether final height in tall boys will really be reduced by treatment with bromocriptine.

Predicting phenotype in steroid 21-hydroxylase deficiency? Comprehensive genotyping in 155 unrelated, well defined patients from southern Germany.

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders. CAH is most often caused by deficiency of steroid 21-hydroxylase. The frequency of CYP21-inactivating mutations and the genotype-phenotype relationship were characterized in 155 well defined unrelated CAH patients. We were able to elucidate 306 of 310 disease-causing alleles (diagnostic sensitivity, 98.7%). The most frequent mutation was the intron 2 splice site mutation (30.3%), followed by gene deletions (20.3%), the I172N mutation (19.7%) and large gene conversions (7.1%). Five point mutations were detected that have not been described in other CAH cohorts. Genotypes were categorized in 4 mutation groups (null, A, B, and C) according to their predicted functional consequences and compared to the clinical phenotype. The positive predictive value for null mutations (ppv(null)) was 100%, as all patients with these mutations had a salt-wasting phenotype. In mutation group A (intron 2 splice site mutation in homozygous or heterozygous form with a null mutation), the ppv(A) to manifest with salt-wasting CAH was 90%. In group B predicted to result in simple virilizing CAH (I172N in homozygous or compound heterozygous form with a more severe mutation), ppv(B) was 74%. In group C (P30L, V281L, P453S in homozygous or compound heterozygous form with a more severe mutation), ppv(C) was 64.7% to exhibit the nonclassical form of CAH, but 90% when excluding the P30L mutation. Thus, in general, a good genotype-phenotype relationship is shown in patients with either the severest or the mildest mutations. A considerable degree of divergence is observed within mutation groups of intermediate severity. As yet undefined factors modifying 21-hydroxylase gene expression and steroid hormone action are likely to account for these differences in phenotypic expression.

GH therapy in juvenile chronic arthritis: results of a two-year controlled study on growth and bone.

Disturbance of growth frequently occurs in children suffering from juvenile chronic arthritis (JCA). Recognition of growth impairment is important because reduced final height is one of the permanent consequences. The aim of this study was to evaluate the efficacy and safety of human GH (hGH) in growth-retarded prepubertal children with JCA. Thirty-five children were tested for GH deficiency (GHD) and randomly assigned to a study and an untreated control group; five were GH deficient and were part of the GHD group. All received glucocorticoids. The study group was treated with 1 IU/kg BW.wk hGH; the GHD group was given 0.5 IU. During 2 yr of hGH treatment growth velocity and height SD score increased compared with baseline values. There was a marked increase in growth velocity in the treated groups, but also some increase in the control group. Plasma levels of IGF-I and IGF-binding protein-3 increased with GH treatment. These results suggest that hGH might be useful in the treatment of growth impairment in JCA. GH may counteract the adverse effects of glucocorticoid therapy, but its effect is dependent on the disease activity. Long-term controlled studies are needed to determine the risks and benefits of GH therapy in JCA.

Musculoskeletal analyses of the forearm in young women with Turner syndrome: a study using peripheral quantitative computed tomography.

Turner syndrome (TS) is associated with multiple skeletal abnormalities. Fracture incidence appears to be increased, but the reasons for this are not entirely clear. In the present study, we used peripheral quantitative computed tomography to evaluate bone mass, density, geometry, and strength of the radial metaphysis and diaphysis as well as maximum forearm muscle cross-sectional area (CSA) in a group of 21 TS patients. These individuals were 19.5 +/- 2.3 yr of age (mean +/- SD; range, 16.2-25.4 yr) and had completed growth after having received GH therapy; all but one were receiving estrogen supplementation. Despite short stature, cross-sectional bone size was normal compared with age-matched healthy controls. However, bone mineral content was decreased, resulting in a low total volumetric bone mineral density. This was due to decreased cortical thickness at both sites of measurement, whereas trabecular volumetric bone mineral density of the metaphysis was normal. Muscular CSA was normal. The relationship between muscle CSA and external bone size was similar between TS patients and healthy young women. However, TS patients had less bone mineral content and cortical CSA relative to muscle CSA than healthy young women, but similar muscle-bone relationships as healthy prepubertal girls. These findings are compatible with a normal adaptation of external bone size to the mechanical loads imposed by the muscle system and a lack of pubertal effect on the endocortical bone surface, despite estrogen supplementation. Bone strength may not be adequate for the relatively high body weight of TS patients (+0.8 SD score), which could contribute to an increased propensity for fractures.

Subcutaneous growth hormone-releasing hormone therapy in growth hormone-deficient children: first year of therapy.

The purpose of this study was to determine the efficacy and safety of GH-releasing Hormone [GHRH-(1-44)] therapy in GH-deficient children. Twenty previously untreated prepubertal children with GHRH deficiency were treated for 1 yr in a multicenter, open label, company-sponsored study with at least 20 micrograms/kg GHRH-(1-44), sc, half at bedtime and half upon awakening. The main effects were enhancement of linear growth, advancement in bone age, and alteration in general blood chemistries and hormonal values. The mean velocity of the entire group increased from 3.6 +/- 1.1 to 8.1 +/- 1.5 cm/yr (P < 10(-4)) at 1 yr of therapy. After 6 months of therapy, 16 were growing at a mean of 9.4 +/- 2.0 cm/yr and were continued on this dose. In 4 patients who were growing at a rate of 5.5 +/- 1.7 cm/yr, the dose was increased to 40 micrograms/kg daily for the second 6 months. The high dose group increased their mean linear growth velocity for the second 6 months while on the higher dose to 7.6 +/- 0.4 cm/yr (P < 10(-2)). This was equal to the mean velocity for the second 6 months of therapy of the 16 subjects who remained on the 20 micrograms/kg daily therapy (7.6 +/- 1.2 cm/yr). Mean advancement of bone age was 1.3 +/- 0.6 yr during the first year of therapy. No adverse changes in general biochemical, hormonal, or pituitary radiographic analyses were noted. No change in fasting glucose or insulin concentrations, or excessive generation of insulin-like growth factor-I concentrations occurred. We conclude that GHRH in a daily dose of 20-40 micrograms/kg for 1 yr was effective in increasing growth velocity in most GHRH-responsive GH-deficient patients. It was well tolerated without side-effects. Glucose intolerance was not noted.

Molecular genetics and pathophysiology of 17 beta-hydroxysteroid dehydrogenase 3 deficiency.

Autosomal recessive mutations in the 17 beta-hydroxysteroid dehydrogenase 3 gene impair the formation of testosterone in the fetal testis and give rise to genetic males with female external genitalia. Such individuals are usually raised as females, but virilize at the time of expected puberty as the result of increases in serum testosterone. Here we describe mutations in 12 additional subjects/families with this disorder. The 14 mutations characterized to date include 10 missense mutations, 3 splice junction abnormalities, and 1 small deletion that results in a frame shift. Three of these mutations have occurred in more than 1 family. Complementary DNAs incorporating 9 of the 10 missense mutations have been constructed and expressed in reporter cells; 8 of the 9 missense mutations cause almost complete loss of enzymatic activity. In 2 subjects with loss of function, missense mutations testosterone levels in testicular venous blood were very low. Considered together, these findings strongly suggest that the common mechanism for testosterone formation in postpubertal subjects with this disorder is the conversion of circulating androstenedione to testosterone by one or more of the unaffected 17 beta-hydroxysteroid dehydrogenase isoenzymes.

Structural analysis of recombinant von Willebrand factor produced at industrial scale fermentation of transformed CHO cells co-expressing recombinant furin.

Thorough analysis of multimer composition and molecular structure of recombinant von Willebrand factor (r-vWF) produced by recombinant CHO cells demonstrated r-vWF to be more intact and less proteolytically degraded than plasma-derived vWF (pd-vWF) [B. Fischer et al. (1994) FEBS Lett. 351, 345-348]. In contrast to pd-vWF, r-vWF preparations consisted of pro-vWF (vWF containing covalently attached propeptide) as well as mature vWF subunits forming homo- and hetero-multimers. In order to ensure complete propeptide processing, a r-vWF-producing CHO cell clone was transfected with the cDNA of the human propeptide processing enzyme Furin. A r-vWF/r-Furin co-expressing cell clone was cultivated at industrial scale in high cell density perfusion fermenters. r-vWF obtained from these cells was fully processed. Analysis of r-vWF by multimer analysis revealed a multimer pattern equal in number of high molecular weight multimer to pd-vWF, but absence of satellite bands. Two-dimensional electrophoretic analysis of both the primary dimer and the complete multimer pattern of r-vWF showed that the recombinant coagulation factor was composed exclusively of intact and mature subunits. Since the triplet structure typical to pd-vWF is known to reflect proteolytic degradation, r-vWF thus exhibits an integrity far superior compared to pd-vWF.