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Spencer Beasley

Publications and source records attributed to Spencer Beasley.

11 recordsLinked to original sources
PubMed2006

Sonic hedgehog expression in the development of hindgut in ETU-exposed fetal rats.

Sonic hedgehog (Shh) has been shown to be involved in the morphogenesis of many organ systems including the notochord, floor plate and limbs, as well as in the development of the left-right axis in vertebrates. Recent evidence suggests the Shh cascade plays a crucial role in the development of the foregut and hindgut. We have previously shown that prenatal exposure of fetal rats to ethylenethiourea (ETU) induces hindgut malformations and other abnormalities of the VACTERL association. The aim of this study was to determine the pattern of expression of Shh and its downstream genes during hindgut development in ETU-exposed embryos with anorectal malformations (ARMs). Pregnant Sprague-Dawley rats were mated together overnight and a positive vaginal plug was marked as gD0. On gD10, 1% ETU (125 mg/kg) was given to the experimental group and controls received the same volume of saline. Embryos were collected from both groups at gD12-16. The developing hindgut of each embryo was dissected under magnification and snap frozen. Highly purified RNA was isolated from each hindgut and first strand cDNA was prepared with appropriate negative controls. Reverse transcriptase (RT) polymerase chain reaction (PCR) was done to determine the transcripts of Shh in each sample and quantitative real-time PCR was carried out to show relative quantitative expression of Shh at each time point. Shh was detected in all samples confirming that Shh is active during the process of hindgut development in fetal rats. Relative quantitation demonstrated that Shh expression shows time-dependent changes in the developing hindgut of ETU-exposed rat embryos, and when results were compared with control samples, there was significant decrease in expression on gD14 and 15, when the cloaca normally separates into the rectum and urethra occurs in the rat fetus. The misregulated expression of Shh in the hindgut of ETU-exposed rat embryos suggests that ETU may interfere with Shh signalling. Downregulation at the time of cloacal separation into rectum and urethra indicates that Shh plays a crucial role in the development of hindgut.

Abnormalities, Multiple↗
PubMed2005

Hereditary thyroglossal duct cysts.

Thyroglossal duct cysts are one of the most commonly encountered benign neck lumps found in the paediatric population. Despite their relative frequency, reports of familial inheritance are rare. A total of 21 patients with hereditary thyroglossal duct cysts from seven families worldwide have been reported. The most common inheritance pattern is dominant, with a minority possibly representing a recessive aetiology. We describe a further instance of dominantly inherited thyroglossal duct cysts in two generations.

Child, Preschool↗
PubMed2004

Adriamycin disruption of the Shh-Gli pathway is associated with abnormalities of foregut development.

BACKGROUND: The hedgehog signalling pathway appears to have a crucial role in the embryogenesis of the foregut in vertebrates. Sonic hedgehog (Shh) protein and gene are involved in the differentiation of many organ systems such as notochord, floor plate, and limbs; development of the left-right axis in vertebrates; and differentiation of trachea and esophagus from the primitive foregut. METHODS: The prenatal exposure of Sprague-Dawley fetal rats to Adriamycin between days 6 and 9 of gestation was used to induce esophageal atresia and tracheoesophageal fistula. Embryos were harvested by cesarean section on gestational days 11 to 15. Embryos were examined by microscopy, dissection, and serial histology. In situ hybridization was used to study Shh gene expression in the rat embryos. RESULTS: In situ hybridization showed that the pattern and level of Shh gene expression are affected by Adriamycin. Adriamycin-treated rats have deformed notochord and undivided foregut, and some of the embryos had a lack of the dorso-ventral patterning of Shh expression seen in control embryos. CONCLUSIONS: These results are consistent with the hypothesis that Adriamycin influences the Shh signalling pathway, resulting in disruption of normal development of the foregut.

Animals↗
PubMed2003

Intussusception.

Explore the source record for details and available documents.

Child↗
PubMed2003

Liver injury in children: causes, patterns and outcomes.

AIM: To compare the causes, patterns and outcomes of hepatic trauma in children with those in adults. METHODS: A retrospective audit was conducted of a five-year period from 1996 of adults and children admitted to Christchurch Hospital with liver injuries. Details of age, mechanism of injury, injury severity score (ISS), radiological grade of liver injury, operations and mortality were recorded and analysed. RESULTS: There were 93 liver injuries over the five-year period: 22 in children and 71 in adults. The median age of each group was 7 and 29 years respectively. The most common causes of injury in children were bicycle (7/22) and motor vehicle accidents (MVAs) (7/22). The majority (37/71) of adult injuries were caused by MVAs. The median length of hospital stay was significantly shorter in the paediatric group: 4 days (range 1-12) in children vs 9 days (range 0-52) in adults. CONCLUSIONS: Liver trauma in children has a different spectrum of causes, and results in more severe liver injury than in adults. However, children are more likely to have an isolated liver injury that results in a shorter length of stay in hospital. A nationwide paediatric-injury surveillance system might allow better identification of preventable causes of injury.

Accidents, Traffic↗
PubMed2003

Differences in the levels of Sonic hedgehog protein during early foregut development caused by exposure to Adriamycin give clues to the role of the Shh gene in oesophageal atresia.

Sonic hedgehog (Shh) protein is a signalling molecule that is important for defining patterning in the development of vertebrates. Shh has been shown to be involved in the morphogenesis of many organ systems such as notochord, floor plate and limbs and in the development of the left-right axis in vertebrates. In this study we show that high levels of protein occur during the initial period of foregut differentiation into trachea and oesophagus, and that low levels of Shh protein are seen during early development of the foregut where oesophageal atresia and/or tracheo-oesophageal fistula ensue. These studies show that Shh protein is expressed in the rat foregut during embryogenesis, and its level declines as the embryo approaches birth. In adriamycin-treated rats the level of Shh protein expression is very low without any time-dependent changes. These results are consistent with the hypothesis that adriamycin influences the Shh signalling pathway, resulting in disruption of normal development of the foregut.

Animals↗
PubMed2003

A simple technique of laparoscopic full-thickness anterior abdominal wall repair of retrosternal (Morgagni) hernias.

BACKGROUND/PURPOSE: Previous reports of laparoscopic repair of Morgagni hernias in children have involved relatively complex laparoscopic techniques. This report describes a simpler method of repair that we have applied to 4 children. METHODS: Four children with retrosternal (Morgagni) hernias underwent primary laparoscopic repair by placement of interrupted synthetic nonabsorbable sutures through the full-thickness of the anterior abdominal wall, incorporating the posterior rim of the defect and returning back out through the anterior abdominal wall, with the sutures tied in the subcutaneous tissue. RESULTS: The children, ranging in age from 11 to 36 months, underwent laparoscopic repair of their Morgagni hernias and had an uneventful postoperative recovery, apart from a port site hernia in one. CONCLUSIONS: This technique for primary laparoscopic repair of Morgagni hernia is easy to perform, well tolerated by the patient, and gives excellent cosmetic results. Laparoscopic closure of the defect by suturing the posterior rim of the hernia to the full thickness of the anterior abdominal wall would appear to provide a safe and effective means of repairing this type of hernia.

Abdominal Wall↗
PubMed2003

Diagnosis and treatment of foregut duplications.

In its broadest sense, the term, foregut duplication encompasses the full spectrum of developmental aberrations of the embryonic foregut (bronchopulmonary and alimentary tract). Evidence is emerging that the notochord may have a pivotal role to play in foregut development through the Shh-GLi signalling pathway. The investigation and management of these lesions depends on the clinical presentation and the level of the foregut affected. The presentation of symptomatic foregut duplications also depends on any space-occupying effect they exert and where specific complications related to the malformation occur, such as when the mucosal lining contains acid-secreting cells. In a minority of cases, (eg, where they cause respiratory compromise or spinal cord compression) urgent intervention is required. In the remainder, precise diagnostic imaging according to the level and location of the foregut duplication provides the necessary information to plan surgical excision of the lesions. Magnetic resonance imaging best shows the relationships of complex bronchopulmonary foregut malformations and associated anomalies of the spine. eg, neurenteric canal. Most lesions can be excised with minimal morbidity. Minimal-access surgical techniques can be applied to the simpler cysts, particularly some bronchogenic cysts. Thoraco-abdominal duplications and neurenteric cysts require careful preoperative delineation and more complex surgery.

Abnormalities, Multiple↗
PubMed2003

J. H. Louw Memorial Lecture. Outreach, origins and a hedgehog.

Professor J. H. Louw is honoured in this lecture for the major contribution he made to the development of paediatric surgery in South Africa as a specialty in its own right. Although he is perhaps best known internationally for his contribution to our understanding of the aetiology of small-bowel atresias, it may be that his greatest legacy lies in those he taught, many of whom are in the audience. He was a man who demanded the highest standards, both of himself and of his colleagues, and despite many other leadership roles and responsibilities in surgery generally, always considered that his first responsibility was to paediatric surgery. It may be fitting, therefore, that this lecture deals with two aspects that were dear to Professor Louw, namely the provision of specialist care for children with surgical conditions, and recent research into the causes of congenital structural abnormalities.

Adolescent↗