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Biomedical subjects

S Tennant

Publications and source records attributed to S Tennant.

11 recordsLinked to original sources
PubMed2004

Identification of a mutation in synapsin I, a synaptic vesicle protein, in a family with epilepsy.

A four generation family is described in which some men of normal intelligence have epilepsy and others have various combinations of epilepsy, learning difficulties, macrocephaly, and aggressive behaviour. As the phenotype in this family is distinct from other X linked recessive disorders linkage studies were carried out. Linkage analysis was done using X chromosome microsatellite polymorphisms to define the interval containing the causative gene. Genes from within the region were considered possible candidates and one of these, SYN1, was screened for mutations by direct DNA sequencing of amplified products. Microsatellite analysis showed that the region between MAOB (Xp11.3) and DXS1275 (Xq12) segregated with the disease. Two point linkage analysis demonstrated linkage with DXS1039, lod score 4.06 at theta = 0, and DXS991, 3.63 at theta = 0. Candidate gene analysis led to identification of a nonsense mutation in the gene encoding synapsin I that was present in all affected family members and female carriers and was not present in 287 control chromosomes. Synapsin I is a synaptic vesicle associated protein involved in the regulation of synaptogenesis and neurotransmitter release. The SYN1 nonsense mutation that was identified is the likely cause of the phenotype in this family.

Adolescent↗
PubMed2004

Walking problems in young children.

This article attempts to define normal development throughout childhood and provide straightforward advice in the physical assessment of the child in this situation. It also attempts to outline the groups of conditions that lead to walking abnormalities and highlight the salient physical features and special investigations that are required to make these diagnoses with confidence.

Child↗
PubMed2002

The Marchetti-Vincenzi humeral nail--a useful device in fresh fractures.

Whilst most humeral fractures may be treated by closed methods, humeral nailing has gained popularity where a surgical option is indicated. Concern has been expressed regarding placement of proximal and distal locking screws whilst the efficiency of the ingenious intra-medullary locking device of the Seidel nail has also been questioned. The Marchetti-Vincenzi nail, which "locks" proximally with the spreading of intra-medullary pins and distally with a single screw inserted via the surgical wound, apparently avoids potential neurovascular and tendon injury. Prospectively recorded data was analysed in 19 "fresh" fractures, i.e. within 3 weeks of injury, and in 13 "late" fractures (total of 32 humeral fractures) treated with the Marchetti nail. All fresh fractures thus treated progressed to union, whilst in the late fracture group there were three non-unions all of whom were in osteoprotic females. Whilst we commend the use of the Marchetti humeral nail in fresh fractures, we have reservations about its use in "late" fractures particularly where the patient is female and osteoporotic.

Adolescent↗
PubMed2001

Patello-femoral tracking in the weight-bearing knee: a study of asymptomatic volunteers utilising dynamic magnetic resonance imaging: a preliminary report.

Normal patello-femoral tracking is not well defined, and conventional radiological techniques do not allow imaging in the physiological, weight-bearing stance. A vertical-access open configuration magnetic resonance scanner allows imaging of patello-femoral tracking during weight-bearing and through a wide range of knee flexion. We imaged 40 asymptomatic knees in this way, producing axial scans which were analysed qualitatively and quantitatively using sulcus angle, congruence angle, lateral patello-femoral angle and patellar centralisation, to assess patellar tilt and displacement. Mild lateral tilting in hyperextension with the quadriceps relaxed was seen, but quantitative assessment of this was impeded by internal rotation of the femur in extension. One-half of the knees were slightly laterally displaced in hyper-extension, becoming central during the first 30 degrees of knee flexion. During passive flexion of the knee in a seated position, fewer knees were laterally tilted or displaced, and no consistent change was seen during flexion. These results indicate that mild lateral tilting and displacement can be normal phenomena in the weight-bearing knee in early flexion and should not necessarily be taken as evidence of abnormal tracking in symptomatic patients. Lateral to medial movement of the patella occurs during normal knee flexion. In addition, imaging in the weight-bearing knee can provide valuable information not gained by imaging during passive knee flexion.

Adult↗
PubMed1999

The use of dynamic interventional MRI in developmental dysplasia of the hip.

Conventional methods of imaging in the investigation of developmental dysplasia of the hip all have disadvantages, either in definition or in exposure to radiation. We describe a new open-configuration MR scanner which is unique in that it allows anaesthesia and access to the patient within the imaging volume for surgical procedures and application of casts. We performed 13 scans in eight anaesthetised infants. Dynamic imaging revealed two dislocated hips which were then visualised during reduction. Hip spicas were applied without removing the patient from the scanner. In one hip, an adductor tenotomy was carried out. In all patients, stressing the hips during dynamic imaging allowed an assessment of stability. This was particularly useful in two hips in which an analysis of stability in different positions facilitated the planning of femoral osteotomies. This method of imaging provides new and important information. It has great potential in the investigation of developmental dysplasia of the hip and, with ultrasound, may allow management without the need for radiography.

Anesthesia, General↗
PubMed1998

A randomized, double-blind, placebo-controlled, crossover study to assess the immediate effect of sublingual glyceryl trinitrate on the ankle brachial pressure index, claudication, and maximum walking distance of patients with intermittent claudication.

PURPOSE: The goal of the present study was to assess the immediate effect of sublingual glyceryl trinitrate (GTN) in patients with intermittent claudication. METHODS: We conducted a randomized, double-blind, placebo-controlled crossover study. Inclusion criteria consisted of history of intermittent claudication, resting ankle brachial pressure index (ABPI) of 1.00 or less, a 20% or greater fall in ABPI after exercise, and maximum walking distance (MWD) of less than 250 m. Patients already receiving nitrates were excluded. In study 1, patients (n = 25) underwent a standard exercise test after randomization to receive either 800 microg of sublingual GTN or placebo. The postexercise ABPI was recorded. Then, the crossover portion of the study was performed. In study 2, patients (n = 22) had their claudication distance and MWD measured. They then were randomized to receive either GTN or placebo spray, and the exercise test was repeated, with the claudication distance and MWD recorded, followed by the crossover portion of the study. Statistical analysis was performed with the Wilcoxon matched pairs signed ranks test and the Mann-Whitney U test. RESULTS: In study 1, the median postexercise ABPIs for placebo and GTN were 0.29 and 0.36 (P =.0001). In study 2, the median claudication distance for both placebo and GTN groups was 70 m (P =.59). The median MWD for the placebo and GTN groups was 105 and 125 m (P =.0084) CONCLUSION: GTN can decrease the fall in ABPI after exercise and increase the MWD.

Administration, Sublingual↗
PubMed1997

Aromatase cytochrome P450 transcripts are detected in fractured human bone but not in normal skeletal tissue.

Peripheral conversion of gender steroid precursors has been implicated in playing a role in bone turnover in postmenopausal women. It has been reported that aromatase cytochrome P450 (P450arom) is present in primary bone and bone marrow (BM), and that P450arom mRNA has been identified in cultured BM and osteoblast-like cell lines. However, there are no reports that P450arom transcripts have been detected in skeletal tissue that has not been cultured. We therefore elected to test for the presence of P450arom mRNA in primary human bone and BM in normal and fractured necks of femora using the reverse transcription-polymerase chain reaction method. Although the RNA extracted from these tissues was of good quality as demonstrated by the expression of transcripts for interleukin-6, P450arom transcripts failed to be detected in normal primary cortical bone and fatty BM containing trabecular bone. However, P450arom transcripts were detected in the latter when they were cultured. Transcripts for P450arom were also detected in total RNA extracted from six fractured necks of femora and semiquantitative PCR demonstrated that P450arom mRNA was present in similar abundance in the same amount of RNA analyzed from buttock adipose tissue and fractured bone/BM. P450arom mRNA expression was also detected in cultured peripheral blood leukocytes, suggesting that this might be the source of the enzyme. In these cultures no correlation was detected between the expression of P450arom mRNA and cell proliferation. PCR failure was excluded in cases when P450arom transcripts failed to be detected in bone/BM by coamplifying RNA from human and rat brain mRNA, known to express P450arom mRNA, using primers that detect both P450arom mRNA from both species. These products were analyzed by Southern blot using oligonucleotide probes, which label either human or rat P450arom cDNA. The blots confirmed the absence of P450arom in nonfractured human bone and BM and preclude PCR failure. Our results indicate that P450arom mRNA is not detected in either normal human bone or BM, but can be induced in this microenvironment under pathological conditions. We propose that tissue grown in vitro is analogous to a wound and this explains why P450arom transcripts were detected in cultured normal skeletal tissue, whereas they failed to be detected in primary normal bone and BM.

Animals↗
PubMed1994

Early reoperation rates after arterial surgery.

Between 1 January 1985 and 31 December 1991, 2426 patients underwent arterial surgery. Three hundred and seventy one reoperations were performed on 258 patients within 30 days of the initial procedure. One hundred and ninety three (52%) of the operations were attempted revascularisations, 95 (26%) were amputations and 58 (16%) were to control bleeding. One hundred and sixty nine (66%) of first operations were successful, but 76 patients required a further 113 reoperations. The mortality of reoperation was 16%, while the mortality of patients not requiring reoperation was 9% (p < 0.01). The mean hospital stay in days was higher in patients requiring reoperation (p < 0.05). Where appropriate, patients should be informed of the significant incidence of reoperation and reoperative mortality after vascular surgery. The increased hospital stay in reoperated patients has financial implications.

Adolescent↗