Comparative study of multiple thiol-based self-assembled monolayer coatings for the SERS detection of nitrite, nitrate, and perchlorate anions in water.

Raman-based sensors represent a promising solution to enable both detection and fingerprinting of anionic pollutants in the water distribution network. Due to the weak nature of Raman scattering, a signal intensity enhancement mechanism, such as surface enhanced Raman spectroscopy (SERS), is required. Given the combination of SERS being a first layer effect and the low affinity for metallic surfaces shown by anions, functionalization of the SERS substrates using positively charged self-assembled monolayers (SAMs) is required to guarantee a strong SERS signal. In this work, the performance of three thiol-based coatings, namely, 2-mercapto-4-methyl-pyrimidine, cysteamine, and 2-dimethyl-amino-ethanethiol, is systematically compared for the detection of nitrite, nitrate, and perchlorate ions in water. For each coating, the limit of detection of those analytes is studied in combination with commercial SERS substrates. Cysteamine-coated SERS substrates are shown to provide the lowest limit of detection for the three analytes of this study. Evaluation of this coating on real drinking water samples is reported.

New insights into factors influencing adult height in short SGA children: Results of a large multicentre growth hormone trial.

BACKGROUND: Growth hormone (GH) treatment is effective in improving adult height (AH) in short children born SGA. However, there is a wide variation in height gain, even after adjustment for predictive variables. It is therefore important to investigate new factors which can influence the response to GH. OBJECTIVE: To investigate the efficacy of GH treatment (1 mg/m(2/) day) in short SGA children on AH. To assess the relation between spontaneous catch-up growth after birth and growth during puberty on the total height gain SDS to AH. PATIENTS: Longitudinal GH trial in 170 children. RESULTS: Median age at start of GH was 7·1 years and height -3·0 SDS. AH was -1·8 SDS (TH-corrected AH -1·1 SDS) in boys and -1·9 SDS (TH-corrected AH -1·3 SDS) in girls. Spontaneous catch-up growth after birth was ≥0·5 SDS in 42% of children. In contrast to expectation, spontaneous catch-up growth was negatively correlated with total height gain SDS during GH (P = 0·009). During puberty, height SDS declined (-0·4 SDS in boys and -0·5 SDS in girls) resulting in a lower total height gain SDS than expected. Pubertal height gain was 25·5 cm in boys and 15·3 cm in girls, significantly lower compared to AGA children (P < 0·001). At onset of puberty, BA for boys and girls was moderately advanced (P = 0·02 and P < 0·001, respectively). Growth velocity was comparable to AGA children during the first two years of puberty, but thereafter significantly lower until reaching AH (P < 0·001). CONCLUSION: In contrast to our hypothesis, children with greater spontaneous catch-up growth after birth show a lower total height gain SDS during GH. Height SDS declines from mid-puberty, due to a marked early deceleration of growth velocity.

Successful treatment of severe subcutaneous insulin resistance with inhaled insulin therapy.

The potential of inhaled insulin therapy for severe resistance to subcutaneous insulin was tested in a 7-yr old boy with type 1 diabetes mellitus. The efficiency of 1 mg inhaled insulin (Exubera) was examined by a 4-h euglycemic clamp study. During the clamp, the glucose infusion rate started to increase 25 min after inhalation and peaked 120 min after inhalation. Subsequently, a trial of inhaled insulin monotherapy was initiated consisting of pre-meal inhalations and one inhalation during the night. Since glycemic control remained fair (HbA1c approximately 8.5%), this therapy was continued. Over the ensuing 18 months, mild keto-acidosis occurred twice during gastro-enteritis. Inhaled insulin was well tolerated and pulmonary function did not deteriorate. We conclude that severe resistance to subcutaneous insulin does not preclude sufficient absorption of insulin delivered by pulmonary.

Growth hormone and the heart in Noonan syndrome.

BACKGROUND: The clinical hallmarks of Noonan syndrome (NS) are facial dysmorphism, short stature and cardiac defects. As one of the common cardiac defects in NS is hypertrophic cardiomyopathy, there have been concerns regarding cardiac safety since the start of human growth hormone (hGH) therapy for NS. METHODS: Review of currently available data on the prevalence of cardiac defects, the theoretical effects of hGH on the heart and the results of studies on the effects of hGH on the heart. RESULTS: The prevalence of cardiac defects in NS is high, and the spectrum is very broad. Progression of ventricular wall thickness during hGH therapy has never been reported. There are barely any data available on children with NS and hypertrophic cardiomyopathy collected during hGH therapy. In post-marketing surveillance studies, there are no reports of adverse cardiac events related to hGH therapy. CONCLUSION: The reported absence of negative effects of hGH therapy on the heart in NS and especially on ventricular wall thickness is reassuring. Still, keeping in mind the current limited experience, any effects on the heart resulting from hGH therapy should be monitored carefully in NS.

Growth in Noonan syndrome.

Growth failure in Noonan syndrome is mainly postnatal of character and is dominated by slow maturation and late puberty. The postnatal early decline seems to be an intrinsic part of the syndrome. Reported adult heights are about -2 SD and are indicative of a secular trend.

Decreased bone density and treatment in patients with autosomal recessive cutis laxa.

AIM: Due to the occasional association pathological fractures and osteoporosis we evaluated four patients with cutis laxa syndrome for skeletal anomalies. PATIENT/METHODS: We prospectively evaluated four patients, a male and a female child and a brother-sister sib pair, with dysmorphic features, growth delay, joint anomalies, psychomotor retardation and congenital cutis laxa. The clinical features and the family history were suggestive for autosomal recessive cutis laxa syndrome type II, partially overlapping with geroderma osteodysplastica. Skeletal survey, sequential bone density measurements, endocrine and metabolic investigations were performed including N- and O-linked glycosylation analysis. ATP6V0A2 and FBLN5 mutations were ruled out in all patients. RESULTS: All children were diagnosed with significantly decreased bone density, especially in the lumbar spine, including spontaneous vertebral and rib fractures in three children. Following 24 months of bisphosphonate treatment a total restitution of bone density was observed in three cases and no relapse was detected in the 2-year follow-up period. A spontaneous improvement was found in one female during puberty. CONCLUSION: Bone disease might occur early in the course in autosomal recessive cutis laxa syndrome. We report on a significant clinical improvement and stabilization in our patients following bisphosphonate therapy. We suggest early, systemic evaluation and follow up of bone density in all children presenting with inherited cutis laxa.

Are ECG abnormalities in Noonan syndrome characteristic for the syndrome?

Of all patients with Noonan syndrome, 50-90% have one or more congenital heart defects. The most frequent occurring are pulmonary stenosis (PS) and hypertrophic cardiomyopathy. The electrocardiogram (ECG) of a patient with Noonan syndrome often shows a characteristic pattern, with a left axis deviation, abnormal R/S ratio over the left precordium, and an abnormal Q wave. The objective of this study was to determine if these ECG characteristics are an independent feature of the Noonan syndrome or if they are related to the congenital heart defect. A cohort study was performed with 118 patients from two university hospitals in the United States and in The Netherlands. All patients were diagnosed with definite Noonan syndrome and had had an ECG and echocardiography. Sixty-nine patients (58%) had characteristic abnormalities of the ECG. In the patient group without a cardiac defect (n = 21), ten patients had a characteristic ECG abnormality. There was no statistical relationship between the presence of a characteristic ECG abnormality and the presence of a cardiac defect (p = 0.33). Patients with hypertrophic cardiomyopathy had more ECG abnormalities in total (p = 0.05), without correlation with a specific ECG abnormality. We conclude that the ECG features in patients with Noonan syndrome are characteristic for the syndrome and are not related to a specific cardiac defect. An ECG is very useful in the diagnosis of Noonan syndrome; every child with a Noonan phenotype should have an ECG and echocardiogram for evaluation.

Impaired Sertoli cell function in males diagnosed with Noonan syndrome.

In order to study male gonadal function in Noonan syndrome, clinical and laboratory data, including inhibin B, were gathered in nine pubertal males diagnosed with Noonan syndrome. Bilateral testicular maldescent was observed in four, and unilateral cryptorchidism occurred in two. Puberty was delayed in three patients. Luteinising hormone (LH) levels were normal in all patients in our series, while follicle stimulating hormone (FSH) levels were raised in seven. Inhibin B was low in six males and just above the lower limit of normal in two. Importantly, all three men with normal testicular descent displayed signs of Sertoli cell dysfunction, indicating, in contrast to earlier reports, that bilateral cryptorchidism does not seem to be the main contributing factor to impairment of testicular function in Noonan syndrome. These findings suggest different mechanisms of disturbance in male gonadal function, which is frequently associated with Sertoli dysfunction.

Response to growth hormone treatment and final height in Noonan syndrome in a large cohort of patients in the KIGS database.

BACKGROUND: Noonan syndrome (NS) is an autosomal dominant inherited disease, characterized by a distinctive facial appearance, congenital heart defects, and short stature. Treatment with growth hormone (GH) is an option to enhance height, but long-term effects are still unclear. PATIENTS AND METHODS: A cohort of 402 patients (269 males, 133 females), mean age 9.7 years at start with GH, was studied within the KIGS International growth database with respect to long-term response to GH therapy and final height after GH therapy. RESULTS: At the start of GH therapy median height was -2.61 SDS (Tanner 1966 standards). Seventy-three patients who were followed longitudinally for 3 years had an increment in height SDS (Ht SDS) over the first 3 successive years of 0.54, 0.13 and 0.13, respectively. Twenty-four patients had reached their final height after 4-12 years of GH treatment. Their Ht SDS increased from a median of -3.28 to a median of -2.41 at final height. CONCLUSION: This group of patients with NS showed an early response to GH treatment, with an attenuation of this effect thereafter. At final height the median increment of final height was 0.61 SDS according to Tanner standards and 0.97 SDS according to Noonan standards. No serious side effects were reported.

[Persistent neonatal hypoglycaemia caused by arterial positioning of the umbilical venous catheter]. / Persisterende onverklaarde neonatale hypoglykemie door arteriële positie van een navelvenelijn.

Two neonates, a girl born at 40 2/7 weeks weighing 4165 g and a boy born at 37 6/7 weeks weighing 4040 g, received umbilical venous catheters to help manage hypoglycaemia. The catheter was ineffective or only effective when high doses of glucose were used, due to what later appeared to be arterial positioning of the catheter. Both patients recovered without consequences. Persistent hypoglycaemia is a common problem in newborns and can cause severe neurological sequelae. A relatively uncommon cause is malpositioning of the umbilical catheter. Positioning in an artery leads to direct infusion of glucose into the pancreas, which causes hyperinsulinaemia and can lead to potentially dangerous nonketotic hypoglycaemia. Arterial positioning of the umbilical catheter should be ruled out at an early stage. Correct catheter positioning can be determined using careful inspection of the umbilical veins, radiological examination of the catheter position, blood gas analysis or vascular pulsation.

Treatment of tall stature in boys with somatostatin analogue 201-995: effect on final height.

BACKGROUND: An optimal treatment for tall stature in boys in terms of efficacy and safety is not available. Treatment with somatostatin analogue 201-995 (SMS) has been tried with positive short-term results. METHODS: We evaluated the effect of SMS treatment on reducing adult height. Over 2 years, 16 boys presenting to our university hospital with tall stature (constitutional tall stature (n = 13), Marfan syndrome (n = 2) and tethered spinal cord (n = 1)) with a predicted final height above 197 cm were included in the study and prospectively followed until final height was reached. As one boy was lost to follow-up we have reported on 15 boys. Treatment with SMS as a single subcutaneous dose was started and continued until final height was reached. In eight boys androgens were given to induce puberty after the start of SMS and five boys were on treatment with androgens prior to SMS treatment. Effect on reduction of final height prediction, calculated with the index of potential height based on the bone age of Greulich and Pyle, was the main outcome measure. Standard anthropometric assessments were performed a year before and every 3 months during treatment. Bone age was assessed by the method of Greulich and Pyle at the start and after 6 and 12 months. RESULTS: Mean reduction in final height prediction (predicted adult height minus achieved adult height) was -0.1 cm (range -6.4 to +5.7). In three boys, asymptomatic microlithiasis of the gall bladder was diagnosed. CONCLUSIONS: We have concluded that, in spite of encouraging short-term results, long-term treatment with SMS does not reduce final height in a manner sufficient to justify SMS treatment in tall stature.

[Central congenital hypothyroidism due to Graves' disease in the mother]. / Centrale congenitale hypothyreoïdie door ziekte van Graves bij de moeder.

Two male twins were born at a gestational age of 30 weeks. Five days after delivery, the mother was diagnosed with Graves' disease. The thyroid function in the neonates was therefore evaluated, which led to the detection of central congenital hypothyroidism (central CHT), even though the neonatal CHT-screening had been reported to be normal. Both boys were treated with thyroxine up to the age of nine months. It was then established that their development had been uneventful. Maternal Graves' disease can, due to the presence of anti-thyroid stimulating hormone (TSH) receptor antibodies and the maternal use of anti-thyroid drugs, result in thyroid dysfunction in the neonate. Neonates born to mothers with Graves' disease are at risk of developing central CHT. This occurs especially in children of mothers who are not treated or are inadequately treated during pregnancy. In view of the importance of thyroid hormone for brain development, children with central CHT are at risk for neurodevelopmental problems if thyroid dysfunction is not detected and treated early. The Dutch screening for congenital hypothyroidism is based on thyroxine (T4), TSH and thyroid-binding globulin. This makes it possible to detect central CHT. However, in prematurely born infants this disease may be missed because in this subgroup, referral is only based on increased TSH levels, which may not be present.

An appraisal of the role of biliary phospholipases in the pathogenesis of gallstone disease.

Human bile contains proteins that influence nucleation of cholesterol. Recently, it has been suggested that activity of phospholipases in bile may play a role in this process. To study the influence of phospholipase on nucleation we have determined the effect of phospholipases A2, C and D on the nucleation time of model bile. Phospholipase C decreased the nucleation time, whereas phospholipase A2 inhibited nucleation. The phospholipases were effective only at relatively high concentrations. Phospholipase D was strongly inhibited in model bile and probably only influenced the nucleation time by an aspecific protein effect. The cleavage products of the different phospholipases were determined in native bile samples of 14 cholesterol gallstone patients, 6 patients without stones and 4 patients with pigment stones. In all samples, choline, phosphorylcholine and free fatty acids (FFA) could be detected. However, there was no significant difference between the three groups of patients. The rate of production of choline, phosphorylcholine and FFA was measured in bile incubated at 37 degrees C. Again, there was no significant difference between the three groups of patients. We conclude that phospholipase activity in bile does not play an important role in the pathogenesis of gallstone disease.

The validity of the cholesterol nucleation assay.

The validity of the cholesterol nucleation assay rests on the assumption that all cholesterol crystals are removed at the start of the assay so that de novo formation of crystals can be studied. In this paper we have tested the validity of this assumption. Cholesterol crystals were added to supersaturated model bile. Subsequently the mixtures were either filtered over a 0.22 micron filter or centrifuged at 37 degrees C for 2 h at 100,000 x g. After ultracentrifugation the isotropic interphase was collected. Using polarized light microscopy no crystals could be visualized in this fraction. However, the nucleation time of the isotropic interphase decreased from 6.8 +/- 1.1 days to 1.8 +/- 0.2 days (mean +/- S.E., P less than 0.01, n = 5) when 10-100 micrograms/ml crystals were added prior to centrifugation. Similar results were observed when instead of centrifugation the mixtures containing crystals were filtered. After filtration over a 0.22 micron filter no crystals could be detected in the filtrate. Yet the nucleation time of the filtrate decreased from 6.4 +/- 0.7 days to 3.1 +/- 0.5 days (mean +/- S.E.) when 10 micrograms/ml cholesterol crystals were added before filtration (n = 10, P less than 0.01). Since no cholesterol crystals could be detected at the start of the assay the reduction in nucleation time must have been brought about by cholesterol microcrystals that passed through the filter. Supplementation of cholesterol crystals to model bile did not accelerate the nucleation time when the samples were passed over a 0.02 micron filter, indicating that the size of the microcrystals was larger than 20 nm. The effect of addition of cholesterol crystals prior to filtration over a 0.22 micron filter was also tested in the crystal growth assay recently developed by Busch et al. ((1990) J. Lipid Res. 31, 1903-1909). Addition of crystals had only a minor effect on the assay. In conclusion, the reduced nucleation time of biles from gallstone patients is probably not only due to the presence of promoting or the absence of inhibiting proteins, but can be caused by the presence of small cholesterol crystals in these biles.

Congenital isolated adrenocorticotropin deficiency: an underestimated cause of neonatal death, explained by TPIT gene mutations.

Tpit is a T box transcription factor important for terminal differentiation of pituitary proopiomelanocortin-expressing cells. We demonstrated that human and mouse mutations of the TPIT gene cause a neonatal-onset form of congenital isolated ACTH deficiency (IAD). In the absence of glucocorticoid replacement, IAD can lead to neonatal death by acute adrenal insufficiency. This clinical entity was not previously well characterized because of the small number of published cases. Since identification of the first TPIT mutations, we have enlarged our series of neonatal IAD patients to 27 patients from 21 unrelated families. We found TPIT mutations in 17 of 27 patients. We identified 10 different TPIT mutations, with one mutation found in five unrelated families. All patients appeared to be homozygous or compound heterozygous for TPIT mutations, and their unaffected parents are heterozygous carriers, confirming a recessive mode of transmission. We compared the clinical and biological phenotype of the 17 IAD patients carrying a TPIT mutation with the 10 IAD patients with normal TPIT-coding sequences. This series of neonatal IAD patients revealed a highly homogeneous clinical presentation, suggesting that this disease may be an underestimated cause of neonatal death. Identification of TPIT gene mutations as the principal molecular cause of neonatal IAD permits prenatal diagnosis for families at risk for the purpose of early glucocorticoid replacement therapy.

[A genetic childhood disease with consequences in adult life: the Denys-Drash syndrome]. / Een genetische kinderziekte met gevolgen op de volwassen leeftijd: Denys-Drash-syndroom.

In a 17-year-old woman with absent sexual development and a congenital nephrotic syndrome leading to renal failure, the Denys-Drash syndrome was diagnosed after development of an ovarian dysgerminoma. The Denys-Drash syndrome is characterised by the triad: progressive nephropathy due to diffuse mesangial sclerosis, male pseudo-hermaphroditism (XY karyotype with ambiguous or female genital organs) and an increased risk of developing Wilms' tumour and gonadoblastoma. The syndrome is generally caused by a genetic defect in the Wilms' tumour suppressor 1 gene (WT1 gene). A WT1 mutation and XY karyotype were also found in this patient. The WT1 gene encodes a transcription factor playing an important role in renal and genital development. The diagnosis of Denys-Drash syndrome had important consequences for the follow-up and treatment of the patient. The second gonad and the native kidneys were removed due to the increased risk of malignancy. Moreover, the finding of a XY karyotype could result in serious psychic problems. Physicians responsible for the health of adults are confronted more and more often with the consequences of childhood diseases. This case illustrates the necessity to inform such physicians about previously untreatable genetic diseases of childhood so that the adequate medical management of these patients can be guaranteed.

Quantification of cholesterol nucleation promoting activity in human gallbladder bile.

We have developed a simple method to quantitate cholesterol nucleation promoting activity in bile. The method makes use of the fact that gallbladder bile of cholesterol gallstone patients contains potent nucleation promoting activity. Gallbladder bile samples were serially diluted, routinely from 1/25 to 1/6,400. The diluted samples were mixed with a supersaturated model bile and the nucleation time (NT) of the mixtures was determined. The greatest dilution that resulted in a significant shortening of the NT was called the nucleation promoting activity titre (NPAT). The determination is independent of the original lipid content of the bile sample. The NPAT was measured in 14 gallbladder bile samples derived from patients with cholesterol gallstones and 9 controls. In all samples promoting activity was found. In the samples from the stone patients the NPAT was significantly elevated as compared to the patients without cholesterol stones (p = 0.01). Our results suggest that the cholesterol saturation index and the activity of cholesterol nucleation promoting factors are the most important factors in the pathogenesis of cholesterol gallstone disease. Assessment of the NPAT allows the differentiation of groups of patients with a normal cholesterol saturation index who are at risk for gallstone formation due to a high NPAT.

Can GnRH-agonist treatment cause slipped capital femoral epiphysis?

Slipped capital femoral epiphysis (SCFE) mainly occurs in pubertal children and is associated with delayed skeletal maturation, obesity, high growth velocity and tall stature. Furthermore, SCFE often coincides with endocrine disorders. This is the first report of a possible relationship between SCFE and GnRH agonist treatment: four patients developed SCFE during or shortly after treatment with GnRH agonists was stopped. We compared the clinical aspects of these patients with patients described in the literature who developed SCFE. Puberty started at the age of 3.3, 9.6, 0.0 and 5.6 years respectively. One patient developed sequential SCFE of both hips. SCFE occurred at the age of 11.9 (patient 1), 12.7 (patient 2), 14.3 (patient 2), 11.3 (patient 3) and 11.3 (patient 4) years. Of the five incidences of SCFE, one occurred during GnRH agonist treatment and four shortly after treatment was stopped. None of our patients met the typical criteria seen in SCFE and no 'regular' characteristics of patients with SCFE could be designated. Probably the hormonal changes during and shortly after treatment with GnRH agonists make the epiphysis more prone to slip. Considering our observations and by reviewing the literature, GnRH agonist treatment might present a risk factor for the occurrence of SCFE.

An adolescent with food-dependent Cushing's syndrome secondary to ectopic expression of GIP receptor in unilateral adrenal adenoma.

ACTH-independent Cushing's syndrome may be secondary to the expression of ectopic hormone receptors in adrenal tissue. In food-dependent Cushing's syndrome the adrenals aberrantly express receptors for gastric inhibitory polypeptide (GIP). We present the first case of food- and GIP-dependent adrenal adenoma in an adolescent. A 15 year-old girl presented with signs of hypercortisolism. Urinary cortisol excretion was clearly elevated. Upon the finding of very low fasting plasma cortisol levels with a rise during the morning, food-dependent cortisol secretion was suspected. Hourly measurements of plasma cortisol and GIP levels during a day with and a day without meals showed meal- and GIP-related cortisol secretion. Plasma ACTH levels were undetectable. Abdominal computed tomography showed a tumor of 2.5 x 2.5 x 2 cm in the left adrenal. Unilateral adrenalectomy was performed and microscopic examination of the tumor showed an adrenocortical adenoma. Incubation of adenomatous cells prepared from this tumor with GIP resulted in increased cortisol secretion. Using RT-PCR amplification and cDNA hybridization, the GIP receptor was found to be overexpressed in the adenoma tissue but not in the adjacent adrenal tissue. Twelve months after the operation, hourly measurements of plasma cortisol, GIP and ACTH levels on a day with and a day without meals no longer showed GIP-related cortisol production. The present report shows that in an adolescent with corticotrophin-independent Cushing's syndrome, food-dependent hypercortisolism is a possible diagnosis.