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Biomedical subjects

G A Russell

Publications and source records attributed to G A Russell.

At least 19 recordsLinked to original sources
PubMed1997

Local staging of prostate cancer with 0.2 T body coil MRI.

This study was undertaken to evaluate the accuracy of low field strength body coil MRI in the staging of clinically localized prostate cancer. Fifty-three patients with prostate cancer were examined on a 0.2 T body coil system before undergoing radical prostatectomy. Of the 20 cases with unconfined stage T3 disease on histology, 12 were correctly staged, whilst three cases were overstaged by MRI. (Accuracy 79.2%, sensitivity 60%, and specificity 90.9%.) The accuracy, sensitivity and specificity for the detection of capsular penetration were 77.3%, 55% and 90.9%, respectively, whilst those for seminal vesical invasion were 94.3%, 83.3% and 95.7%, respectively. It is concluded that a high level of staging accuracy, comparable to that obtained in some published studies using high field strength endorectal coil MRI, can be obtained using 0.2 T body coil MRI.

Aged↗
PubMed1995

Randomised controlled trial of allopurinol prophylaxis in very preterm infants.

Allopurinol, an inhibitor of xanthine oxidase (an enzyme capable of generating superoxide radicals following hypoxiaischaemia), was investigated in preterm infants to determine its ability to prevent the complications of neonatal intensive care which may be associated with oxidative injury. Four hundred infants of between 24 and 32 weeks' gestation were randomly allocated to receive enteral allopurinol (20 mg/ml) or an equivalent dose of placebo for seven daily doses. At admission, plasma hypoxanthine concentrations were significantly higher in infants who subsequently developed periventricular leucomalacia (PVL), bronchopulmonary dysplasia (BPD), or retinopathy of prematurity (ROP), but there was no difference in the primary endpoint (PVL) between the treated and control groups. The failure of allopurinol prophylaxis in this group of infants is probably related to the complex nature of the pathological processes and to the timing of treatment. If oxidant injury is an important mechanism of cellular injury in these preterm infants, an alternative biochemical modulator would be required, or a combination of agents might be effective.

Allopurinol↗
PubMed1994

Antioxidants and neonatal lung disease.

Bronchopulmonary dysplasia (BPD) remains a clinical problem in survivors of neonatal intensive care despite recent advances which include surfactant replacement. Oxygen toxicity may well be a component in the pathogenesis of BPD and disturbance of the oxidant-antioxidant balance constitutes a biochemical problem which should be addressed in the management of preterm babies. Preterm babies appear to have inadequate antioxidant potential and yet when delivered may experience considerable oxidant stress. This imbalance may be ameliorated by antenatal steroid therapy which augments pulmonary antioxidants as well as surfactant production. Augmentation of antioxidants by administration of exogenous enzymes such as superoxide dismutase and catalase is possible in animal models but the clinical use of such therapies awaits further research.

Antioxidants↗
PubMed1993

Extra-pharyngeal neck pathology complicating pharyngeal pouch surgery.

One case each of: (1) low grade thyroid lymphoma; (2) supraclavicular and para-oesophageal metastasis of a uterine adenocarcinoma; and (3) recurrent multinodular goitre have been encountered in very intimate relationship with the neck of a pharyngeal pouch within the tracheo-oesophageal gutter raising the possibility that the two conditions were interrelated. The practical importance of these cases is that a surgeon excising a pouch from the neck ought to be able to resect a thyroid lobe should it prove necessary, and occasionally endoscopic diverticulotomy is the only reasonable option.

Aged↗
PubMed1992

Squamous metaplasia in the penile urethra due to oestrogen therapy.

Histological examination was performed on the anterior penile urethra from 21 asymptomatic trans-sexual patients taking oestrogens prior to surgery. Squamous metaplasia was present in 15 of these patients and in 1 man taking progesterones. Immunohistochemical staining for oestrogen receptors in the urethra was negative. Severe squamous metaplasia was associated with patchy chronic inflammatory cell infiltration but this was also present in normal controls. The lack of recognised complications of squamous metaplasia at this site suggests that it is an incidental observation in men taking oestrogens.

Adult↗
PubMed1992

Plasma hypoxanthine: a marker for hypoxic-ischaemic induced periventricular leucomalacia?

Cerebral ischaemia of the immature brain may result in cavitating periventricular leucomalacia (PVL), an important association of cerebral palsy. Hypoxanthine measured by high performance liquid chromatography was used as a marker of peripartum hypoxia and ischaemia in 116 infants at risk of PVL. PVL was detected by ultrasound. The 81 infants who were unaffected had median (range) gestation of 30 weeks (24-32), weight of 1336 g (724-3790), and a plasma hypoxanthine concentration of 7.8 mumol/l (2.4-48.9). The seven infants who had cavitating PVL had a median gestation of 28 weeks (26-30), weight of 1165 g (682-1860), and a hypoxanthine concentration of 31.9 mumol/l (7.1-149). Cavitating PVL was significantly dependent only on hypoxanthine when controlling for the effects of weight and gestation. This suggests that peripartum hypoxia-ischaemia may be one of the aetiological factors in cavitating PVL. Oxidation of hypoxanthine during reperfusion generates free radicals which may contribute to the tissue destruction of PVL. The association of hypoxia-ischaemia with PVL suggests that PVL may be modified by reducing free radical activity.

Biomarkers↗
PubMed1992

Receiver operating characteristic curves for comparison of serial neutrophil band forms and C reactive protein in neonates at risk of infection.

The performance of indirect indices of infection in the newborn vary because of differences in techniques, including diagnostic cut off levels. We have compared serial neutrophil band cell counts with C reactive protein measured by rate nephelometry. The 'gold standard' was a positive culture and the performance of the tests was compared by the technique of receiver operating characteristics (ROC) as well as sensitivity and specificity. A total of 172 septic screens were performed in 56 patients. The operational diagnostic cut off values were: C reactive protein greater than 8 mg/l, immature:total neutrophil ratio (I:T ratio) greater than 0.2, and band count greater than 5%. Compared with the sensitivity of C reactive protein (71%), I:T ratio (34%) was significantly different but band count (69%) was not. The specificity of C reactive protein (72%) was better than band count (39%) but no better than I:T ratio (73%). ROC curves were constructed for all possible diagnostic cut off values of the tests and superior performance was demonstrated for C reactive protein compared with band count and I:T ratio. We conclude that C reactive protein is a useful early indicator of infection in neonates and that ROC curves permit comprehensive and graphic comparison between tests and the calculation of optimal diagnostic cut off values.

Bacteria↗
PubMed1991

Autoimmune Addison's disease and thyrotoxic thyroiditis presenting as encephalopathy in twins.

An 11 year old boy who presented with neuropsychiatric symptoms including delirium and pronounced agitation was found to have simultaneous onset of autoimmune adrenocortical insufficiency and hyperthyroidism. His identical twin also had hyperthyroidism and six months later developed symptoms of adrenocortical insufficiency. In children presenting with neuropsychiatric symptoms, adrenal (or pituitary) and other endocrine disorders should be considered.

Addison Disease↗
PubMed1991

Patterns of ductal tissue in coarctation of the aorta in the first three months of life.

A possible relationship between recurrence of coarctation and the presence of residual ductal tissue in the aorta was studied by defining the presence and pattern of ductal tissue in aortic segments from 23 patients less than 3 months of age who underwent resection of coarctation of the aorta. The surgical policy was to perform extensive excision of the coarctation, including a wide margin of descending aorta beyond the ductus arteriosus. Histologic examination showed that there was a circumferential sling of ductal tissue extending from the ductus arteriosus and surrounding the aorta at the level of the coarctation shelf in 22 specimens. In 15 of these specimens one or two tonguelike prolongations of ductal tissue extended distally from the circumferential sling and occupied constant positions in the aortic wall; one tonguelike prolongation extended distally below the insertion of the ductus and the other from the circumferential sling opposite the ductal insertion. Incomplete excision of ductal tissue was found in 11 specimens. In relation to the goal of avoiding recurrent coarctation after repair in the early months of life, the possible implications of these findings are discussed, and, in particular, a possible mechanism of recurrence after subclavian flap aortoplasty is proposed.

Aortic Coarctation↗
PubMed1989

Studies on adenosine triphosphate transphosphorylases. XVIII. Synthesis and preparation of peptides and peptide fragments of rabbit muscle ATP-AMP transphosphorylase (adenylate kinase) and their nucleotide-binding properties.

Two peptide fragments, derived from the head and tail of rabbit muscle myokinase, were found to possess remarkable and specific ligand-binding properties (Hamada et al., 1979). By initiating systematic syntheses and measurements of equilibrium substrate-binding properties of these two sets of peptides, or portions thereof, which encompass the binding sites for (a) the magnesium complexes of the nucleotide substrates (MgATP2- and MgADP-) and (b) the uncomplexed nucleotide substrates (ADP3- and AMP2-) of rabbit muscle myokinase, some of the requirements for binding of the substrates to ATP-AMP transphosphorylase are being deduced and chemically outlined. One requirement for tight nucleotide binding appears to be a minimum peptide length of 15-25 residues. In addition, Lys-172 and/or Lys-194 may be involved in the binding of epsilon AMP. The syntheses are described as a set of peptides corresponding to residues 31-45, 20-45, 5-45, and 1-45, and a set of peptides corresponding to residues 178-192, 178-194, and 172-194 of rabbit muscle adenylate kinase. The ligand-binding properties of the first set of synthetic peptides to the fluorescent ligands: epsilon MgATP/epsilon ATP and epsilon MgADP/epsilon ADP are quantitatively presented in terms of their intrinsic dissociation constants (K'd) and values of N (maximal number of moles bound per mole of peptide); and compared with the peptide fragment MT-I (1-44) obtained from rabbit muscle myokinase (Kuby et al., 1984) and with the native enzyme (Hamada et al., 1979). In addition, the values of N and K'd are given for the second set of synthetic peptides to the fluorescent ligands epsilon AMP and epsilon ADP as well as for the peptide fragments MT-XII(172-194) and CB-VI(126-194) (Kuby et al., 1984) and, in turn, compared with the native enzyme. A few miscellaneous dissociation constants which had been derived kinetically are also given for comparison (e.g., the Ki for epsilon AMP and the value of KMg epsilon ATP obtained for the native enzyme) (Hamada and Kuby, 1978), and the K'd measured for Cr3+ ATP [corrected] and the synthetic peptide I1-45 (Fry et al., 1985b).

Adenosine Diphosphate↗
PubMed1989

Coexistent cardiac tumours and malformations of the heart.

Cardiac tumours and anatomical malformations of the heart may produce similar clinical signs and symptoms. The coexistence of these two abnormalities complicates diagnosis and probably adversely affects prognosis. We present a review of four cases of this rare combination. In the first case, Ebstein's malformation was present in a child with tuberous sclerosis and cardiac rhabdomyomata. Right ventricular rhabdomyomata were associated with a hypoplastic tricuspid valve in the second case. In the third case, cardiac myxomas were detected in a child with a double-chambered right ventricle. The fourth case was a child with a fibroma of the right ventricle with pulmonary atresia. We propose that, in some circumstances, a space-occupying lesion may be associated with, or possibly induce, a malformation within the developing heart.

Ebstein Anomaly↗
PubMed1989

Aspergillus ball thrombus occluding a homograft conduit.

Almost total occlusion of an aortic homograft conduit by a ball of Aspergillus terreus was found postmortem in a 6-month-old infant following repair of a type I truncus arteriosus. Signs of pulmonary hypertensive crisis, fever, anaemia, and thrombocytopenia were present. However, blood cultures were persistently negative. A 2-D echocardiogram failed to demonstrate any vegetation. The clinical, pathological, and postmortem findings are described and difficulties in the diagnosis of Aspergillus infection are discussed.

Aspergillosis↗
PubMed1989

Flecainide toxicity.

Flecainide toxicity occurred in an infant being treated for refractory atrioventricular re-entry tachycardia. Ventricular tachycardia developed when dextrose was substituted for milk feeds. We believe that milk was interfering with the absorption of flecainide, and so a high serum concentration developed when milk feeds were stopped.

Animals↗
PubMed1989

Postmortem audit in a paediatric cardiology unit.

Postmortem examinations performed on 76 children with a clinical diagnosis of congenital heart disease were reviewed retrospectively and compared with the findings before death. Both operated and unoperated cases were studied over a three year period. Despite intensive investigation during life, there was a high rate of unsuspected abnormalities at necropsy (80%): 29 cases had undiagnosed additional cardiac anomalies or surgical flaws, which contributed to death in 13 cases. Defects in surgery were uncommon but permitted modification in surgical technique to avoid recurrence. Myocardial necrosis and pulmonary foreign body embolism were common findings, the importance of which is uncertain and requires further study for their prevention. Even in the most thoroughly investigated cases postmortem examination has a high yield of clinically important pathology which is undetected during life.

Autopsy↗
PubMed1988

Post mortem radiology in children with congenital heart disease.

Contrast radiology has valuable applications in routine necropsy practice. Contrast radiology was used to study the vascular anatomy in four normal fetuses, in five children with cardiovascular malformations, and in two hearts prepared by the perfusion fixation method. A contrast radiograph provides permanent documentation of anatomical associations before they are disrupted by dissection and permits a planned approach to the necropsy. While these injection studies are seldom undertaken by pathologists because they are felt to be too difficult and time-consuming, contrast studies should form part of the post mortem investigation of children with congenital heart disease, even when angiography has been performed in life.

Autopsy↗