The role of the sonic hedgehog signalling pathway in patients with midline defects and congenital hypopituitarism

INTRODUCTION

The Gli family of zinc finger (GLI) transcription factors mediates the sonic hedgehog signalling pathway (HH) essential for CNS, early pituitary and ventral forebrain development in mice. Human mutations in this pathway have been described in patients with holoprosencephaly (HPE), isolated congenital hypopituitarism (CH) and cranial/midline facial abnormalities. Mutations in Sonic hedgehog (SHH) have been associated with HPE but not CH, despite murine studies indicating involvement in pituitary development.

OBJECTIVES/METHODS

We aimed to establish the role of the HH pathway in the aetiology of hypothalamo-pituitary disorders by screening our cohort of patients with midline defects and/or CH for mutations in SHH, GLI2, Shh brain enhancer 2 (SBE2) and growth-arrest specific 1 (GAS1).

RESULTS

Two variants and a deletion of GLI2 were identified in three patients. A novel variant at a highly conserved residue in the zinc finger DNA-binding domain, c.1552G > A [pE518K], was identified in a patient with growth hormone deficiency and low normal free T4. A nonsynonymous variant, c.2159G > A [p.R720H], was identified in a patient with a short neck, cleft palate and hypogonadotrophic hypogonadism. A 26·6 Mb deletion, 2q12·3-q21·3, encompassing GLI2 and 77 other genes, was identified in a patient with short stature and impaired growth. Human embryonic expression studies and molecular characterisation of the GLI2 mutant p.E518K support the potential pathogenicity of GLI2 mutations. No mutations were identified in GAS1 or SBE2. A novel SHH variant, c.1295T>A [p.I432N], was identified in two siblings with variable midline defects but normal pituitary function.

CONCLUSIONS

Our data suggest that mutations in SHH, GAS1 and SBE2 are not associated with hypopituitarism, although GLI2 is an important candidate for CH.

From adaptive licensing to adaptive pathways: delivering a flexible life-span approach to bring new drugs to patients

The concept of adaptive licensing (AL) has met with considerable interest. Yet some remain skeptical about its feasibility. Others argue that the focus and name of AL should be broadened. Against this background of ongoing debate, we examine the environmental changes that will likely make adaptive pathways the preferred approach in the future. The key drivers include: growing patient demand for timely access to promising therapies, emerging science leading to fragmentation of treatment populations, rising payer influence on product accessibility, and pressure on pharma/investors to ensure sustainability of drug development. We also discuss a number of environmental changes that will enable an adaptive paradigm. A life‐span approach to bringing innovation to patients is expected to help address the perceived access vs. evidence trade‐off, help de‐risk drug development, and lead to better outcomes for patients.

Current means of obtaining a MD degree in the UK

To investigate the current means of obtaining a MD a questionnaire was sent to 55 doctors who had obtained a MD in a paediatric subject between 1984 and 1993; 53 (93%) responses were obtained. Ten (18%) of the respondents had done their MD during a clinical post. The remainder had research posts lasting 10-87 months (median 24). Only 29% of those in research posts were able to submit their MD by the end of their post. The time from starting [corrected] the MD to confirmation that it had been obtained was 21-102 months (median 54). Of those in research posts 0-80% (median 20) of their time was spent on non-research related activities and 45% had regular on call commitments. It took 2-15 months (median 6) before candidates received their MD back from their examiners. Altogether 46% of candidates had to make revisions to their MD and 47% of candidates had a viva. There is great variation in the current means of obtaining a MD and it is suggested that nationwide regulations are adopted for the conduct of MD degrees.

Continuous negative extrathoracic pressure in neonatal respiratory failure

OBJECTIVE

In uncontrolled clinical trials, negative extrathoracic pressure has been shown to be an effective respiratory support. We aimed to assess its role in the context of current neonatal intensive care.

DESIGN

A randomized controlled trial, with sequential analysis of matched pairs of infants. Matching was undertaken by stratified randomization from 15 groups divided according to gestational age, oxygen requirement, and whether patients were intubated at 4 hours of age.

SETTING

Two neonatal intensive care units.

PATIENTS

Two hundred forty-four patients (birth weight 1.53 +/- 0.69 kg (mean +/- SD); gestational age 30.4 +/- 3.5 weeks) with respiratory failure.

INTERVENTIONS

Patients were randomized at 4 hours of age to receive either standard neonatal intensive care, or standard care plus continuous negative extrathoracic pressure (CNEP, -4 to -6 cmH2O) applied within a purpose-designed neonatal incubator. OUTCOME SCORES: Clinical scores were calculated for each infant at 56 days of age, or death if earlier. Scores included measures for mortality, respiratory outcome, the presence of cerebral ultrasound abnormalities, patent arterial duct, necrotizing enterocolitis, and retinopathy. The treatment given for the higher score for each pair was recorded and the cumulative net number of pairs favoring CNEP plotted in the sequential analysis to provide an ethical early termination strategy. Individual components of the outcome score and other secondary measurements were analyzed on completion of the trial.

RESULTS

The sequential analysis reached a decision boundary after 122 out of a possible maximum of 124 pairs were completed. The overall outcome score showed an overall significant benefit for CNEP. Secondary analysis showed that the use of CNEP was associated with an increase in mortality, cranial ultrasound abnormalities, and pneumothoraces, which were not statistically significant. However, 5% fewer patients were intubated (95% confidence interval [CI], 0-10), and the total duration of oxygen therapy among surviving infants at 56 days was lower (20.5 days, compared with 38.9 in controls; difference 18.4 days, 95% CI 3.8 to 33.0). Among all infants, the mean total duration of oxygen therapy was 18.3 days among CNEP-treated infants compared with 33.6 days among the controls (difference -15.3 days, 95% CI -0.2 to -30.4). This reduction in mean levels is entirely attributable to substantially fewer patients requiring prolonged oxygen therapy, the median duration of treatment being very similar in the two groups. As a result, commensurately fewer surviving infants showed chronic lung disease of prematurity.

CONCLUSIONS

The use of continuous negative pressure improves the respiratory outcome for neonates with respiratory failure.

Continuous negative extrathoracic pressure and cardiac output--a pilot study

Continuous negative extrathoracic pressure (CNEP) has been recently reintroduced as therapy for respiratory failure. To determine its effects on cardiac output a pilot study was performed in ten patients aged 2 months-3 years (median 4 months). All had chronic respiratory failure (seven with bronchopulmonary dysplasia). Five were breathing spontaneously and five were intubated and undergoing intermittent positive pressure ventilation. Transcutaneous oxygen saturation and PCO2, together with ECG were continuously monitored. Pulmonary artery blood flow velocity was measured non-invasively using pulsed wave Doppler. The 95% confidence intervals for the changes with and without CNEP in spontaneously breathing and ventilated patients showed no statistically significant changes in heart rate, O2 saturation, transcutaneous PCO2 or cardiac output. This study shows that the use of CNEP, administered in a tank respirator, does not lead to large changes in cardiac output.

Negative extrathoracic pressure ventilation for phrenic nerve palsy after paediatric cardiac surgery

OBJECTIVE

To investigate the feasibility of negative extrathoracic pressure ventilation as a respiratory support following phrenic nerve palsy after cardiac surgery.

DESIGN

An uncontrolled pilot study.

PATIENTS

14 patients aged one week to 30 months (median 5.3 months) with phrenic nerve palsy diagnosed by phrenic nerve conduction tests and diaphragmatic electromyograms. Four had bilateral and 10 unilateral palsy. Before treatment all required oxygen and 10 were receiving positive pressure ventilation. One of the patients with bilateral and four of the patients with unilateral palsies had undergone a plication before negative pressure ventilation was started.

INTERVENTION

Treatment was started 6-65 days (median 23) after operation with a newly designed system which included a Perspex chamber, which gave easy access to the child, and an elastic latex neck seal. Continuous negative pressure was used in conjunction with intermittent positive pressure ventilation while continuous or intermittent negative pressure ventilation was used in extubated infants.

RESULTS

All four patients with bilateral palsy survived with long-term intermittent negative pressure ventilation and did not require further surgery. Of the 10 with unilateral lesions, seven required no further surgery, two underwent plication, and one had a re-plication. Three patients with unilateral palsy died of non-respiratory causes. The duration of positive pressure ventilation after starting negative pressure ranged from 0 to 23 days (median 6). Treatment with negative pressure lasted for 3-241 days (median 32) and was predominantly administered off the intensive care unit, including at home.

CONCLUSIONS

Negative pressure ventilation may be an alternative to positive airway pressure ventilation in the management of phrenic nerve palsy. A multicentre randomised controlled trial is now required to assess further the role of negative pressure ventilation in phrenic nerve palsy.

Fibreoptic bronchoscopy without general anaesthetic

We have used flexible fibreoptic bronchoscopy using sedation and local anaesthesia in 50 children aged 2-19 years (median 10) using an Olympus BFP20 instrument. Indications were opportunistic pneumonias (n = 11), persistent atelectasis (n = 11), recurrent pneumonia (n = 7), miscellaneous lower airway disease (n = 7), recurrent wheezing (n = 3), haemoptysis (3), to diagnose infection or rejection of heart-lung transplants (n = 3), stridor (n = 2), suspected airway compression (n = 1), evaluation of tracheostomy (n = 1), and suspected foreign body (n = 1). In 43 cases (86%) the diagnosis was related to the primary indication. In five (10%) unrelated abnormalities were found, and five (10%) were normal. In 13 (26%) treatment was altered as a result of flexible fibreoptic bronchoscopy. Complications were transient respiratory arrest (n = 2), hypoxia (n = 2), pneumonia (n = 2), and laryngospasm (n = 1). All complications were followed by complete recovery. Our results suggest that flexible fibreoptic bronchoscopy is safe. Advantages over rigid bronchoscopy include greater visual range, fewer complications, and the avoidance of a general anaesthetic. Though invasive it can yield important diagnostic and therapeutic information.

Fatal persistent pulmonary hypertension presenting late in the neonatal period

Two cases of fatal idiopathic persistent pulmonary hypertension presented late in the neonatal period. Lungs were examined histologically by light and electron microscopy, and immunocytochemical studies were used to identify nerves. There was extension of medial smooth muscle distally along the arterial pathway so that most precapillary arteries had completely muscular walls, which in some cases completely obliterated the vessel lumen. Enlarged endothelial cells also contributed to the reduction in the size of the lumen. Nerve fibres accompanying muscular arteries were found in the alveolar region, more distal than is normal. The predominant neuropeptide was the vasoconstrictor tyrosine. Possible aetiological factors in persistent pulmonary hypertension of the newborn are increased muscularity of the peripheral pulmonary arteries antenatally, an increase in the number of vasoconstrictor nerves, or an imbalance in the production of leukotrienes and prostacyclins in the perinatal period.

Hepatopathy-thrombocytopenia syndrome--a complication of dactinomycin therapy for Wilms' tumor: a report from the United Kingdom Childrens Cancer Study Group

We have observed hepatopathy, associated with thrombocytopenia, in children receiving chemotherapy for Wilms' tumor. We have studied this hepatopathy-thrombocytopenia syndrome (HTS) in patients enrolled in the United Kingdom Childrens' Cancer Study Group (UKCCSG) Wilms' tumor trials (UKW1 and UKW2). At the time of this study, 501 patients had completed therapy. Treatment flow sheets were examined for evidence of hepatopathy (hepatomegaly with abnormal liver function tests) and severe thrombocytopenia (platelet count less than 25 x 10(9)/L). No child who developed the syndrome had received irradiation. HTS was seen in five of 355 (1.4%) of patients treated with combination chemotherapy but in none of the 146 patients treated with vincristine alone. In each instance, the onset was less than 10 weeks after diagnosis. In two children, hepatopathy was severe with jaundice, ascites, transaminases greater than 1,000 IU/L, and prolongation of prothrombin time. On average, HTS lasted 12 days, and resolved with supportive treatment. After recovery, the children tolerated chemotherapy, mostly at reduced dosage, without recurrence. There was no evident long-term morbidity. Dactinomycin is the probable cause of this syndrome. We conclude that the HTS is a rare but important complication of dactinomycin-containing combination chemotherapy for Wilms' tumor. Children developing "isolated" thrombocytopenia following dactinomycin are "at risk" of developing the full-blown syndrome and should have their treatment modified accordingly.

Tetralogy of Fallot with anomalous pulmonary venous connections: a rare but clinically important association

Anomalous pulmonary venous connections were found in seven (0.6%) of 1183 patients with tetralogy of Fallot. Three patients had totally anomalous connections (one supracardiac, one direct to coronary sinus, and one mixed supracardiac and infracardiac) and four patients had partially anomalous pulmonary venous connections. All patients presented with the clinical features of tetralogy of Fallot. Anomalous pulmonary venous drainage was suspected clinically in only one patient in whom there was a scimitar sign on the chest radiograph. The exact diagnosis was established by cross sectional echocardiography (one), preoperative or postoperative angiography (five), or at necropsy (one). Surgery was performed in six patients. Total correction without re-routing of the anomalously draining veins was successful in all those with partially anomalous connections, with no significant long term sequelae (follow up median 17 years). Of those with totally anomalous connections, the full diagnosis was made only at necropsy in one patient, successful one-stage correction was performed in one, and the other patient, who had partially obstructed mixed drainage, died shortly after one-stage correction. Histological examination of the lung biopsy specimen in this patient showed grade 2 pulmonary vascular disease. Tetralogy of Fallot with anomalous pulmonary venous connections is a rare association. Careful preoperative assessment is required in those with totally anomalous connections.

Unknown syndrome: microcephaly, hypoplastic nose, exophthalmos, gum hyperplasia, cleft palate, low set ears, and osteosclerosis

We report a neonate, born at term, with microcephaly, a hypoplastic nose, exophthalmos, gum hyperplasia, cleft palate, and low set ears, who died at 86 minutes of age. Radiographs showed diffuse sclerosis of the bones.

Absence of Y specific DNA sequences in two siblings with 46XX hermaphroditism

We report two siblings with 46XX hermaphroditism in whom we were unable to show the presence of Y specific DNA sequences using the DNA probes Y-190, GMGY-7, pHY2.1, pDP34, and 27a. We conclude that an autosomal or X chromosome gene mutation is the most likely mechanism of inheritance in this family with 46XX hermaphroditism.

Multiple idiopathic emboli in a full term neonate

We report a case of multiple idiopathic emboli leading to cerebral infarction and to limb ischaemia in a full term neonate. The increased frequency of diagnosis of cerebral infarction is highlighted. Treatment of cerebral and limb emboli is discussed and the need for further research into the causes and treatment of cerebral infarction is stressed.

Sex pheromone of blackheaded fireworm,Rhopobota naevana (Lepidoptera: Tortricidae), a pest of cranberry

Splitless capillary gas chromatography indicated the presence of (Z)- and (E)-11-tetradecenyl acetate and (Z)-11-tetradecenyl alcohol in the washes of female abdominal tips of the blackheaded fireworm,Rhopobota naevana (Hubner). Gas chromatography combined with mass spectroscopy confirmed the presence of tetradecenyl acetate in extracts of female tips. The low levels observed in these extracts (< 1 ng/female equivalent), prevented further chemical and spectroscopic identification. These materials were found to be stimulatory at low levels in electroantennogram studies. A combination of 9 μg of (Z)-11-tetradecenyl acetate and 3 μg of (Z)-11-tetradecenyl alcohol on rubber septa in wing traps provided an effective attractant. (Z)-9-Dodecenyl acetate, a previously reported attractant, did not significantly increase field trapping catches when added to the binary mixture, but was found to enhance trap catches when added to each of the primary components.

Mycoplasma-like bodies in the saliva of the leafhopper Macrosteles fascifrons (Stål) (Homoptera:Cicadellidae)

A method of feeding leafhoppers on agar to detect microorganisms in their saliva was developed and used with groups of six-spotted leafhoppers, Macrosteles fascifrons (Stål), transmitting aster yellows and groups not transmitting the disease. Mycoplasma-like bodies ranging in size from 30 to 400 mμ were found in the saliva and salivary sheaths of both groups. The structure of the salivary sheaths is described.

LEAFHOPPER TRANSMISSION OF WITCHES' BROOM AND CLOVER PHYLLODY VIRUSES FROM BRITISH COLUMBIA TO CLOVER, ALFALFA, AND POTATO

The leafhoppers, Scleroracus dasidus Med. and Scleroracus balli Med., transmitted witches' broom virus from clover and alfalfa to clover, alfalfa, and potato; and from potato to clover, but not from potato to potato. Where flowering parts occurred, they appeared normal.The leafhoppers also transmitted clover phyllody virus from clover to clover, in which it caused phyllody, and to potato, in which it caused symptoms of witches' broom. Scions of these potatoes infected with clover phyllody virus grafted to tomato produced the same symptoms as a phyllody-inducing strain of potato witches' broom virus.