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Biomedical subjects

A Lander

Publications and source records attributed to A Lander.

At least 19 recordsLinked to original sources
PubMed2005

The use of high resolution magnetic resonance imaging in the prenatal diagnosis of fetal nuchal tumors.

Fetal magnetic resonance imaging (fetal MRI) is an important adjunct to antenatal imaging especially when neonatal surgery is contemplated. We report two cases of fetal nuchal tumors, which were diagnosed incidentally on an ultrasound scan and had fetal MRI to aid diagnosis, prognosis, counseling and management planning. In the first case, fetal MRI aided diagnosis and prenatal multidisciplinary management of a cervical teratoma. Tracheal involvement could not be excluded and an ex-utero intrapartum treatment procedure was planned. Postnatal MRI and angiography provided further information prior to surgery. In the second case, fetal MRI assisted thorough counseling following the finding of a cervical lesion thought to be a cervical teratodermoid, a multicystic hygroma or congenital lymphectasia. The parents opted for termination of the pregnancy. Postmortem findings confirmed the extent of involvement of surrounding structures diagnosed prenatally. The mass was found to be a hamartomatous hemangiolymphangioma.

Adult↗
PubMed2004

Congenital malformations of the diaphragm: findings of the West Midlands Congenital Anomaly Register 1995 to 2000.

OBJECTIVES: To describe trends in incidence, associated anomalies, clinical outcomes and sensitivity of prenatal diagnosis for congenital malformations of the diaphragm in the West Midlands Region between 1995 and 2000. METHODS: Information was retrieved from a population-based register of major congenital malformations in a health region of England, the West Midlands Congenital Anomaly Register (WMCAR), between 1995 and 2000. RESULTS: One hundred and sixty-one confirmed cases of congenital malformations of the diaphragm were notified from 396 577 births. This gives an incidence of 4.1 per 10,000 births. After natural losses and terminations, the incidence at birth was 2.9 per 10,000 registered births. For live-born cases, the infant mortality rate was 317 per 1000 births. 47% of the cases had additional structural or chromosomal anomalies; the infant mortality rate for these complex cases was 533 per 1000, an increased relative risk of 2.37 compared with isolated lesions. 66% of the cases were diagnosed prenatally, 51% of isolated lesions and 84% of complex cases. Fourteen prenatally diagnosed cases (12%) were false-positives; however, 11 of these cases had other significant pathology. These 14 cases were not included in the 161 confirmed cases. CONCLUSION: Congenital malformations of the diaphragm remain associated with considerable infant mortality. Most cases are now diagnosed before birth and the prognosis is adversely affected by the presence of other structural or chromosomal anomalies. This presents significant challenges for those involved in counselling the parents of affected fetuses.

Chromosome Aberrations↗
PubMed2001

Single-system ectopic ureter: a 15-year review.

Ectopic ureters present in childhood with symptoms related to an abnormal site or structure (refluxing, obstructed) of the ureteric orifice. The majority drain duplex kidneys. The diagnosis is relatively easy if the poles are functioning or hydronephrotic. Associated malformations are rarely seen and the results of surgery are gratifying. If an ectopic ureter drains a single kidney, it is called a single-system ectopic ureter (SSEU). We reviewed a 15-year experience (1980-1995) with 127 ectopic ureters from our hospital:11 SSEUs in ten consecutive children were managed during this period. Our data lead us to believe that SSEUs are a special subset of ectopic ureters. Diagnosis is often delayed because the ectopic ureter may be associated with a single small, dysplastic, poorly-functioning, non-visualised kidney and the child may be thought to have a contralateral normal "solitary kidney". Associated systemic malformations are common. Residual symptoms of wetting may persist in the early postoperative period. A high degree of suspicion must be maintained for this entity when a child presents with urinary symptoms of wetting or recurrent infection and a "solitary kidney". Early endoscopic examination of the genitourinary tract will clinch the diagnosis in the majority of cases. Residual symptoms of wetting in the postoperative period generally resolve with passage of time.

Child, Preschool↗
PubMed1998

Exomphalos (omphalocele)

Exomphalos affects approximately 3 in 10,000 births and can arise from a number of developmental insults. The clinical outcome is dependent upon the associated structural and chromosomal anomalies and the gestation at delivery. Accurate antenatal ultrasound diagnosis and karyotyping are important and allow informed prenatal and postnatal management decisions to be made. Prenatal care and counselling should be multidisciplinary and information should ideally be given to parents regarding prognosis and outcome based on prospectively collected population-based data.

Adult↗
PubMed1998

Left-right development: mammalian phenotypes and conceptual models.

Consistent left-right asymmetry in a population requires a special kind of developmental specification. Models of this process must account for the complex phenotypes seen when left-right is abnormal. In some human and mouse mutations, there appears to be a randomisation of global situs to either solitus or inversus, whereas in the inv/inv mouse essentially all are inversus. However, in these and all additional examples there are frequently other anomalies, including symmetry (isomerism) and discordance between organs (heterotaxia). Current models invoke a molecular chiral referent as the source of the primary handed information. We describe a new two-gradient model which accommodates all defects of situs whilst leaving the primary asymmetry unaltered.

Animals↗
PubMed1997

Cisapride reduces neonatal postoperative ileus: randomised placebo controlled trial.

AIM: To assess the efficacy of cisapride in reducing ileus persisting to the tenth postoperative day after neonatal abdominal surgery. METHODS: A prospective, randomised, double blind trial comparing rectal cisapride (1.4-2.3 mg/kg/day) with placebo over seven days was undertaken in 33 neonates. RESULTS: Seven of 12 (58%) patients receiving placebo and eight of 11 (73%) receiving cisapride achieved a first sustained feed during treatment. Of those receiving cisapride, the first sustained feed occurred at 2.3 days (SEM 0.6) compared with 4.7 days (SEM 0.8) with placebo. By the seventh day the mean daily net enteral balance was 69 (SEM 18) ml/kg in the cisapride subgroup and 17 (SEM 8) ml/kg for those receiving placebo. Stool was passed on 6.3 (SEM 0.4) treatment days in the cisapride subgroup compared with 4.1 (SEM 1.0) treatment days in the placebo subgroup. CONCLUSION: Cisapride is effective in neonates with a prolonged ileus after abdominal surgery.

Administration, Rectal↗
PubMed1996

Cell proliferation in mammalian gastrulation: the ventral node and notochord are relatively quiescent.

During gastrulation, the node of the mammalian embryo appears to be an organising centre, homologous to Hensen's node in the chick and the dorsal lip of the amphibian blastopore. In addition, the node serves as a precursor population for the head process, notochord and foregut endoderm. We have studied node architecture and cell morphology by electron microscopy, and cell proliferation using bromodeoxyuridine incorporation and mitotic counts. The dorsal (ectodermal) and ventral (endodermal) components of the node are two distinct populations, separated by a basement membrane. The ventral node, contiguous with the head process, is characterised by a relatively low proliferation rate, with only approximately 10% of cells incorporating BrdU over 4 hr, compared to > 95% in surrounding mesodermal and ectodermal tissues. This is the case from the beginning of node formation, at the no-allantoic-bud stage, until the 7 somite stage, and is not compatible with the idea that the ventral node is a stem cell population. The dorsal node is highly proliferative, its rate of division being indistinguishable from the neurectoderm, with which it is contiguous. In the ventral node, two regions can be recognised: cells in the "pit" are columnar and all monociliated; around them lies a "crown" of cells arranged radially in a horseshoe shape and less often ciliated. Node derivatives share common features with the ventral node; the head process and the notochord are relatively quiescent; and some head process cells are also monociliated. Node and head process monocilia are immotile and appear to be associated with non-proliferation. We suggest that the ventral node contains all the properties of the organiser, while the dorsal node is indistinct from the surrounding epiblast. The cranial end of the foregut pouch, the thyroid diverticulum, and the promyocardium of early somite stage embryos are also areas of low cell division. All the described regions of relative quiescence are sites of expression of members of the TGF beta family, which may be involved in maintaining non-proliferation.

Animals↗
PubMed1995

Interdomain interactions of radixin in vitro.

We have assayed the domains of the ERM protein radixin for binding activities in vitro. Affinity columns bearing the amino-terminal domain of radixin selectively bound a small subset of the proteins of the chicken erythrocyte cytoskeleton. Two of those proteins were identified as radixin itself and band 4.1. In contrast, the carboxyl-terminal domain of the molecule bound neither protein, and full-length radixin did not bind band 4.1 (binding of full-length radixin to itself was not evaluated). Columns bearing a mixture of the amino- and carboxyl-terminal domains of radixin also failed to bind radixin and band 4.1. These results suggested that the amino- and carboxyl-terminal sequences can interact with one another either in cis or in trans, and so interfere with radixin's interactions with other ligands. Using affinity co-electrophoresis, we confirmed a direct interaction in solution between the two radixin domains; the data are consistent with the formation of a 1:1 complex with a dissociation constant of approximately 5 x 10(-8) M. Competition between intramolecular and intermolecular interactions may help to explain the provocative and dynamic localization of ERM proteins within cells.

Animals↗
PubMed1993

Experimental pathogenicity of Sporothrix schenckii preserved in water (Castellani).

Five strains of Sporothrix schenckii preserved in sterile distilled water were found morphologically stable, viable and pure after a period ranging from 16 to 13 years, in the mycology section culture collection from the Instituto de Medicina Tropical, Universidad Central de Venezuela. Each strain was inoculated into the testes of 3 hamsters. All the animals developed disseminated sporotrichosis.

Animals↗
PubMed1992

Intravascular haemolysis in association with necrotising enterocolitis.

Severe haemolysis is an unusual occurrence in association with necrotising enterocolitis (NEC). Activation of the Thomsen-Friedenreich (T) antigen on the neonatal erythrocytes is proposed as the mechanism. This haemolytic process is precipitated by transfusion with serum-containing blood products, which should therefore be avoided. Once haemolysis has become established the outcome is usually fatal. This report describes the management of four neonates who had established haemolysis complicating severe NEC. T activation was confirmed in two infants, but could not be tested for in the other two. Exchange transfusion abolished the haemolysis in two patients, who survived. Despite reduced use of blood products the other two infants died. We believe that exchange transfusion was essential in the successful management of the infants who survived, and recommend early exchange transfusion when haemolysis complicates NEC.

Antigens, Tumor-Associated, Carbohydrate↗