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Biomedical subjects

Rodney C G Franklin

Publications and source records attributed to Rodney C G Franklin.

15 recordsLinked to original sources
PubMed2006

The nomenclature, definition and classification of hypoplastic left heart syndrome.

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

Diagnosis, Differential↗
PubMed2005

Cardiac muscle cell cytoskeletal protein 4.1: analysis of transcripts and subcellular location--relevance to membrane integrity, microstructure, and possible role in heart failure.

The spectrin-based cytoskeleton assembly has emerged as a major player in heart functioning; however, cardiac protein 4.1, a key constituent, is uncharacterized. Protein 4.1 evolved to protect cell membranes against mechanical stresses and to organize membrane microstructure. 4.1 Proteins are multifunctional and, among other activities, link integral/signaling proteins on the plasma and internal membranes with the spectrin-based cytoskeleton. Four genes, EPB41, EPB41L1, EPB41L2, and EPB41L3 encode proteins 4.1R, 4.1N, 4.1G, and 4.1B, respectively. All are extensively spliced. Different isoforms are expressed according to tissue and developmental state, individual function being controlled through inclusion/exclusion of interactive domains. We have defined mouse and human cardiac 4.1 transcripts; other than 4. 1B in humans, all genes show activity. Cardiac transcripts constitutively include conserved FERM and C-terminal domains; both interact with membrane-bound signaling/transport/cell adhesion molecules. Variable splicing within and adjacent to the central spectrin/actin-binding domain enables regulation of cytoskeleton-binding activity. A novel heart-specific exon occurs in human 4.1G, but not in mouse. Immunofluorescence reveals 4.1 staining within mouse cardiomyocytes; thus, both at the plasma membrane and, interdigitated with sarcomeric myosin, across myofibrils in regions close to the sarcoplasmic reticulum. These are all regions to which spectrin locates. 4.1R in human heart shows similar distribution; however, there is limited plasma membrane staining. We conclude that cardiac 4.1s are highly regulated in their ability to crosslink plasma/integral cell membranes with the spectrin-actin cytoskeleton. We speculate that over the repetitive cycles of heart muscle contraction and relaxation, 4.1s are likely to locate, support, and coordinate functioning of key membrane-bound macromolecular assemblies.

Amino Acid Sequence↗
PubMed2005

Prolapse of the antero-superior leaflet of the tricuspid valve secondary to congenital anomalies of the valvar and sub-valvar apparatus: a rare cause of severe tricuspid regurgitation.

Congenital anomalies of the tricuspid valve, and/or its supporting apparatus, leading to severe tricuspid regurgitation are rare. Although well tolerated in early childhood, long-standing and progressive volume loading of the right heart leads to symptoms of decreased exercise tolerance, and may predispose to arrhythmias in the long term. We report three cases of severe tricuspid regurgitation related to anomalies of the cords supporting the antero-superior leaflet of the tricuspid valve. Shortened cords leading to tethering of the leaflet were seen in two cases, and hypoplasia of the leaflet in the other. In all cases, the regurgitant jet was directed posteriorly towards the coronary sinus and atrial septum. Surgical repair was possible in one case, while it proved necessary to replace the valve in a second. The third child is asymptomatic and under regular review.

Child↗
PubMed2005

A survey of professionals delivering secondary care regarding their requirements for paediatric cardiac services as provided by specialists.

The provision of outreach services by paediatric cardiac centres enhances the choice for both parents and professionals. We have conducted a survey to investigate the processes for information and communication at times of interface between specialist and local services for cardiac disease. Based on the responses, we suggest that distance from, and level of contact with, the specialist centre may influence satisfaction and the perceived usefulness of more information. We suggest strategies to increase contact, and make more effective targeting of resources.

Cardiology↗
PubMed2005

Expression of human membrane skeleton protein genes for protein 4.1 and betaIISigma2-spectrin assayed by real-time RT-PCR.

The proteins, spectrin and 4.1 confer support and resilience to animal cell membranes, and promote assembly of multimeric, membrane-bound signalling complexes. Protein 4.1 also plays important roles in tumour suppression and the regulation of cell proliferation. To assess relative tissue expression of the four genes encoding human protein 4.1, we measured mRNA levels using quantitative real-time polymerase chain reaction. We compared 4.1 expression with that of a major splice variant of spectrin, betaIISigma2 that has a shortened C-terminus lacking a pleckstrin homology domain. mRNA for 4.1R is four-fold higher in bone marrow than in tissues with the next highest prevalence: cerebellum, lung, testis and thymus. 4.1G mRNA is highly expressed in brain, spinal cord and testis; 4.1N in brain, spinal cord and adrenal gland; 4.1B in testis, brain, spinal cord, and kidney. Thus, 4.1N, 4.1B and 4.1G all show high accumulation in nervous tissues. mRNA for betaIISigma2-spectrin is ubiquitous, but most abundant in cardiac and nervous tissues. Comparative transcript abundance was analysed in heart and brain. betaIISigma2-spectrin was the most abundant transcript in heart with levels 5 fold greater than 4.1G or 4.1N and at least 9 fold greater than 4.1B. In brain, 4.1N was the most abundant transcript, with levels 2.4 fold greater than 4.1B and at least 4 fold greater than 4.1G or betaIISigma2-spectrin. 4.1R abundance was very low in both tissues. Whilst we expected that 4.1 mRNAs would feature highly in muscle and nerve, we note their high abundance in testis, indicating previously unsuspected functions in reproduction.

Blood Proteins↗
PubMed2002

Fetal pulmonary valvuloplasty for critical pulmonary stenosis or atresia with intact septum.

Progressive stenosis of the semilunar valves in utero can be life threatening. We treated two fetuses with complete or almost complete pulmonary atresia and imminent hydrops (increased cardiothoracic ratio, pericardial effusion, holosystolic tricuspid regurgitation extending into diastole, and abnormal venous Dopplers). We dilated the pulmonary valve of two fetuses in utero at 28 and 30 weeks' gestation, through the mothers' abdomens. After the procedure, the fetuses had decreased signs of circulatory failure and gestation continued until near term. In the neonatal period, we did a repeat valvuloplasty with systemic-to-pulmonary arterial shunt. Both children (now aged 18 months and 12 months) now have biventricular circulation. Surgery on selected fetuses with semilunar valve stenosis or atresia, or both, can extend pregnancy and favourably change the postnatal surgical options.

Catheterization↗