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Biomedical subjects

R Allan

Publications and source records attributed to R Allan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sentinel lymph node biopsy in malignant melanoma: a series of 100 consecutive patients.

A consecutive cohort of 100 patients who had undergone sentinel lymph node biopsy (SLNB) was analysed retrospectively. Three areas were studied: success in finding the sentinel node(s); complications of the procedure; and extra costs incurred by SLNB. The sentinel node(s) were successfully identified in 98% of the lymph node basins biopsied. The overall complication rate was 33%. The additional cost of the procedure was estimated at 1420 pounds sterling per patient. SLNB can reliably identify the sentinel node. However there is a significant complication rate of the technique and considerable additional costs. SLNB requires further critical evaluation before it can be accepted as a standard treatment for patients with malignant melanoma.

Adolescent↗
PubMed2000

Splenic mast cell tumour and mastocytaemia in a cat: case study and literature review.

CASE: An 11-year-old female domestic shorthaired cat presenting with clinical signs of depression, anorexia, weight loss, fever, anaemia and a mid-abdominal mass was referred for abdominal ultrasound examination. CLINICAL FINDINGS: Ultrasonography of the abdomen identified a markedly enlarged spleen. Ultrasound-guided fine-needle aspiration biopsy of the spleen revealed a uniform population of mast cells, 11% of which were observed to have phagocytosed erythrocytes. It is speculated that this may have been a contributing factor in the development of anaemia in this case. Mast cells were detected in a peripheral-blood smear and a diagnosis of systemic mastocytosis (splenic mast cell tumour together with mastocytaemia) was made. This diagnosis was subsequently confirmed by histopathology of the spleen. CONCLUSION: Splenectomy and treatment with corticosteroids appears to have resulted in remission of clinical signs and anaemia. A reduction in the concentration of mast cells in the peripheral blood had not occurred 6 weeks postsplenectomy, but was evident by 10 months post-splenectomy.

Journal Article↗
PubMed1999

Impact of an aggressive stenting strategy on initial and one-year follow-up costs in patients undergoing coronary angioplasty.

BACKGROUND: Although stents have been shown in randomised trials to reduce restenosis rates compared with balloon angioplasty, there are concerns regarding the cost-effectiveness of an aggressive stenting strategy. Stents were shown to increase medical costs over 12 months in the early trials. AIM: Our aim was to determine the economic impact of an aggressive stenting strategy using current stenting techniques compared with a conservative stenting strategy. METHODS: Initial and one year follow-up costs were determined in all patients who underwent successful revascularisation during June to December 1996 (aggressive stenting, n = 401), and compared to all patients treated in the corresponding months in 1995 (conservative stenting, n = 347). All patients had clinical follow-up for one year. RESULTS: The proportion of patients receiving a stent increased from 22.5% in 1995 to 66.1% in 1996 (p < 0.0001). Requirement for repeat procedures in the 1995 group compared with 1996 was coronary angiography in 31% vs 16% (p < 0.001), coronary angioplasty in 11% vs 6% (p = 0.0044) and bypass surgery in 4.8% vs 2.5% (p = 0.054). The mean initial cost of the procedure was higher in the aggressive stenting group ($4319 +/- 1276 in 1995 vs $5131 +/- 1491 in 1996, p < 0.0001), but after 12 months follow-up, total medical costs were equivalent ($5975 +/- 4143 in 1995 vs $5994 +/- 3476 in 1996, p = NS). CONCLUSION: An aggressive coronary stenting strategy is associated with higher initial costs compared with a conservative strategy, but lower costs during follow-up due to reduced need for repeat procedures, resulting in equivalent one year total medical costs.

Angioplasty, Balloon, Coronary↗
PubMed1998

Group psychotherapy for patients with coronary heart disease.

Group therapy with cardiac patients is a relatively new specialty. The field is supported by a substantial epidemiological and experimental literature demonstrating links between heart and mind. There are several clinical trials that have demonstrated less morbidity, improved quality of life, and, to some extent, lower mortality for patients who have received psychosocial intervention, generally group therapy, compared to control patients. Different theoretical orientations and a small number of clinical techniques have been developed to help cardiac patients make an adjustment to heart-healthy living. This article provides a brief review of the literature in cardiac psychology, suggestions for developing a psychotherapy practice specialty with cardiac patients, techniques for treating these patients, and conclusions by a psychologist-cardiologist team that has been active in this area for more than a decade.

Coronary Disease↗
PubMed1998

Alterations in classical cadherins associated with progression in ulcerative and Crohn's colitis.

Human colitis is a condition associated with a spectrum of altered morphologic changes and cellular adhesion. The role of cadherins, which are powerful morphoregulatory cell adhesion molecules, in colitis is provocative and as yet unknown. Herein, we present results that suggest a strong correlation between the deregulation of two cadherin molecules, E- and P-cadherins, and the progression of human colitis. We examined the expression and structural integrity of E- and P-cadherins in inflamed, dysplastic, or neoplastic human ulcerative colitis (UC) (n=58), human Crohn's colitis (n = 30), and normal tissue (n = 20) to assess cadherin function in normal and abnormal epithelium. E-cadherin is strongly expressed in normal colorectal epithelium, whereas in left-sided UC it is either down-regulated or has a single-base pair mutation in exon 4 resulting in an amino acid alteration (6 of 58 UC cases). By contrast, P-cadherin is dramatically up-regulated in both Crohn's disease and ulcerative colitis and especially in dysplastic ulcerative tissue. In vitro transfected SW-480 colorectal cells containing E-cadherin mutations identical to those in vivo were associated with increased spontaneous disaggregation compared with cells transfected with wild-type E-cadherin. Based on this evidence, we hypothesize that a small subset of colorectal cells expressing mutant E-cadherin are associated with widespread ulceration, whereas those expressing P-cadherin are associated with a rapidly dividing immature phenotype that includes dysplasia. The differential expression of mutated and wild-type cadherins examined herein are associated with a broad spectrum of abnormal epithelial phenotypes, lymphocyte integrin binding, and resistance to denudation, as is seen in the colitis adenocarcinoma sequence.

Adult↗
PubMed1996

The role of common carotid artery end-diastolic velocity in near total or total internal carotid artery occlusion.

OBJECTIVES: To evaluate the role of the end-diastolic velocity (EDV) in the common carotid artery (CCA) as a marker of internal carotid artery (ICA) occlusion. DESIGN: Validation of retrospective data in a prospective clinical study. METHODS: The EDV in 94 patients with total ICA occlusion and in 24 patients with high grade (95-99%) unilateral ICA stenosis identified on extracranial carotid colour-flow Duplex imaging (CFDI) and arteriography was reviewed, and was retrospectively compared to the EDV of 176 normal individuals. Identification of patients with ICA occlusion was most accurate (99.3%) with an ipsilateral EDV > or = 12 cm/s and a DIFF > or = 10 cm/s (DIFF = contralateral EDV -- ipsilateral EDV). These values were then prospectively applied to all 886 patients (67 with high grade stenosis or occlusion) who underwent CFDI at our institution during 1994. RESULTS: The EDV > or = 12 had a 92% sensitivity, a 99.4% negative predictive value (NPV) and a 85% specificity in distinguishing between occluded and patent ICA's. In combination with a DIFF > or = 10 was 80.4% sensitive and 97.5% specific. The positive predictive value of the EDV > or = 12 in the distinction between 95-99% ICA stenosis and ICA occlusion was 78.3%, and that of the combination was 85.4%. The EDV was rarely zero and 10% of patients with normal or minimally diseased ICA's had an EDV > or = 12 and/or a DIFF > or = 10. CONCLUSIONS: The EDV < or = 12 cm/s is a sensitive marker of ICA occlusion with a high NPV and in combination with the DIFF > or = 10 cm/s, is specific. Nevertheless, EDV parameters are inaccurate in the distinction of 95-99% ICA stenosis from occlusion. Low EDV can be found in a number of patients with minor or no ICA disease, particularly in those with a stroke or silent cerebral infarct.

Adult↗
PubMed1996

Pictorial review: the radiological spectrum of vertically-acquired HIV infection.

Anonymous antenatal and newborn screening demonstrates a positive HIV seroprevalence of one in 400 in areas of inner city London. European Collaborative Study data show a vertical transmission rate of 15% and suggests that 23% of infected children will develop clinical manifestations of AIDS before reaching 1 year of age [1], meaning that recognition of the radiological findings in vertically-acquired HIV is important. 75 serial cases of vertically-acquired HIV (age range 6 weeks to 12 years, mean age 35 months) presenting to a national referral centre over 48 months were reviewed; the radiographic findings we describe constitute a core of typical abnormalities together with a selection of the rarer manifestations of vertically-acquired HIV.

AIDS-Related Complex↗
PubMed1995

Detection of obstructive uropathy in the fetus: predictive value of sonographic measurements of renal pelvic diameter at various gestational ages.

OBJECTIVE: The goal of our study was to analyze the fetal renal pelvic diameters measured sonographically at several gestational intervals in live-born neonates subsequently found to have either obstructive uropathy or normal kidneys. This information will improve the efficacy of sonography in the diagnosis of obstructive uropathy. SUBJECTS AND METHODS: From an ongoing prospective study assessing the significance of fetal renal pelvic diameters of 4 mm or more at obstetric sonography, the findings in 29 obstructed kidneys in 24 babies were compared with the findings in 380 kidneys from 233 infants who had no obstruction. Twenty-three infants had unilateral obstruction of the ureteropelvic junction, two had unilateral renal obstruction at the ureterovesical junction, one had posterior urethral valves and in addition had both kidneys obstructed because of obstruction at the ureterovesical junction, one kidney was obstructed because of megaloureter, and one kidney was obstructed because of obstruction in a duplex collecting system. Obstruction was identified on nephrostograms, excretory urograms, or radionuclide renograms. The sonographic findings were compared at three gestational age ranges: 16-23 weeks' gestation, 24-30 weeks' gestation, and 31-40 weeks' gestation. The progression of pelvic dilatation in both groups (12 obstructed and 86 unobstructed) was analyzed for the subset of kidneys examined in all three time periods. RESULTS: At 16-23 weeks' gestation, the difference in mean pelvic diameter between obstructed and unobstructed kidneys was not statistically significant, but the difference between obstructed and unobstructed groups at 24-30 weeks' and 31-40 weeks' gestation was significant (p < .001). Renal pelvic diameter showed a much greater rise in diameter through pregnancy in the obstructed group than in the unobstructed group (p < .0003). The sensitivity of the cutoff point of 4-mm renal pelvic diameter for detecting obstruction was 76% before 23 weeks' gestation, including kidneys with a marked decrease in function postnatally; the sensitivity of a 10-mm cutoff point at 16-23 weeks' gestation was 12%. The likelihood that a fetus had renal obstruction increased with increasing diameter of the fetal renal pelvis in all three time periods. CONCLUSION: Kidneys with significant obstruction postnatally may have no dilatation of the renal pelvis before 23 weeks' gestation. Most obstructed kidneys had pelvic diameters of less than 10 mm before 23 weeks' gestation. During pregnancy, renal pelvic diameter increases at a greater rate in kidneys that later are shown to be obstructed than in those that are not obstructed.

Female↗
PubMed1994

Diagnosis of intraventricular hemorrhage in the newborn: value of sonography via the posterior fontanelle.

OBJECTIVE: Intraventricular hemorrhage in neonates with normally sized ventricles is overlooked when sonograms obtained via the anterior fontanelle fail to show a small amount of blood in the occipital horns of the lateral ventricle. Because visualization of the occipital horns is improved when sonograms are obtained via the posterior fontanelle, we studied the efficacy of posterior fontanelle sonography in establishing the diagnosis of intraventricular hemorrhage for 259 neonates. MATERIALS AND METHODS: We compared cranial sonograms obtained via both the anterior and the posterior fontanelles for 34 infants who had intraventricular hemorrhage and whose mean age at birth was 28 weeks (range, 23-40 weeks) with sonograms for 225 neonates who did not have hemorrhage and whose mean age at birth was 31 weeks (range, 24-42 weeks). Sonograms were assessed for satisfactory visualization of the occipital horns of the lateral ventricles, for the characteristics of intraventricular hemorrhage, if present, and for ventricular size, assessed as normal or showing mild, moderate, or marked dilatation. The technique of posterior fontanelle sonography involves obtaining parasagittal views of the occipital horns of the lateral ventricles and coronal scans of the occipital horns at the level of the calcarine fissure. The data from the contrasting groups of neonates were analyzed with Student's t-test or 2 x 2 tables as appropriate. Five autopsies were done; two confirmed intraventricular hemorrhage, and three confirmed the absence of intraventricular hemorrhage. RESULTS: Sonograms obtained via the posterior fontanelle were satisfactory for 92% of neonates born at less than 32 weeks' gestation and 88% of all neonates scanned. The mean age at birth of those with satisfactory sonograms obtained via the posterior fontanelle was 29 weeks (SD, 4 weeks); in comparison, a mean age at birth of 35 weeks (SD, 5 weeks) was associated with unsatisfactory sonograms (p < .0001). Intraventricular hemorrhage was detected via the posterior fontanelle but not via the anterior fontanelle on the initial diagnostic scan for 14 neonates. The ventricles were more likely to be normally sized when intraventricular hemorrhage was seen via the posterior fontanelle only (86%) than when intraventricular hemorrhage was seen via the anterior fontanelle as well (50%) (Fisher's exact test; p = .04). CONCLUSION: Our results show that sonograms obtained via the posterior fontanelle increase the rate of detection of intraventricular hemorrhage in neonates with normally sized ventricles.

Cerebral Hemorrhage↗
PubMed1993

Anti-TNF therapy inhibits fever in cerebral malaria.

The clinical effects of a murine monoclonal antibody (CB0006) directed against tumour necrosis factor were investigated in an open study of 41 Gambian children receiving otherwise conventional therapy for cerebral malaria. Ten children received a single i.v. dose of CB0006 at 0.1 mg/kg, 10 received 1 mg/kg, 10 received 5 mg/kg, and 11 were randomly selected as controls. CB0006 rapidly formed complexes with tumour necrosis factor, which were cleared from the circulation over several days. This was associated with a dose-dependent increase in total plasma tumour necrosis factor levels and a dose-dependent reduction of fever, implying that CB0006 inhibits tumour necrosis factor by retaining it in the circulation and reducing its availability to tissue receptors. Parasite clearance rates were not impaired. The fatality rate (29% overall) was similar in CB0006-treated patients and controls, but evaluation of possible effects on mortality requires a much larger blinded study. These data show that tumour necrosis factor is involved in the pathogenesis of malaria fever, and are the first direct evidence that inhibition of a specific endogenous pyrogen can attenuate fever in man.

Animals↗
PubMed1992

Development of oligonucleotide primers and probes against structural and regulatory genes of human immunodeficiency virus type 1 (HIV-1) and their use for amplification of HIV-1 provirus by using polymerase chain reaction.

The polymerase chain reaction is a powerful technique for amplifying a few copies of double-stranded genetic material to millions of copies in a few hours. The sensitivity and specificity of the polymerase chain reaction technique depend to some extent on the nucleotide sequences of the oligonucleotide primer pair used in the amplification. We report new oligonucleotide primers and probes which can be used for the amplification and detection of human immunodeficiency virus type 1 provirus sequences of not only structural but also regulatory genes. These primers are very sensitive and specific and can be used for the detection of African and North American strains of human immunodeficiency virus type 1.

Adult↗
PubMed1990

Tuberculosis of the thyroid bed presenting as recurrent medullary thyroid carcinoma.

A 69-year-old lady with previous medullary thyroid carcinoma treated by total thyroidectomy alone developed a swelling in the neck. This was thought to be a recurrence of her carcinoma but was found on investigation to be a tuberculous abscess of the thyroid bed. She was treated successfully by surgical drainage and antituberculous chemotherapy.

Abscess↗
PubMed1989

The use of a caries detector dye in cavity preparation.

The aim of this study was to compare the conventional visual and tactile method of detecting carious dentine during cavity preparation using a mirror, probe and excavator with a visual method enhanced by a dye. The dye, 1% acid red in propylene glycol, was used on 100 cavities prepared by dental students and passed as clinically satisfactory by their teachers. Results showed dye stain at the enamel-dentine junction in 57 cavities (57%) which had been assessed as caries-free in this area using conventional visual and tactile means. Subsequent laboratory work on extracted carious teeth confirmed histologically that the dye stains demineralised dentine. If clinicians consider it important to render the enamel-dentine junction caries-free, it might be prudent to use the dye as an aid to diagnosis in this area.

Coloring Agents↗