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Biomedical subjects

S Cross

Publications and source records attributed to S Cross.

At least 73 records · Page 4Linked to original sources

Audit of complete axillary dissection in early breast cancer.

The role of complete axillary dissection (CAD) in the management of breast cancer is controversial and largely unresolved. Acceptance of the results of trials incorporating CAD assumes that the axillary dissection is truly complete. To address this point, and also to define quality control criteria for this operation within our unit, we audited 100 consecutive axillary dissections as follows: the primary surgeon performed what he/she felt to be a thorough CAD and submitted separately the contents of level I, II and III for pathological evaluation; a second surgeon then independently assessed the dissection and arbitrarily labelled any further excised tissue as level IV. Level IV nodes were retrieved in 38% of cases. Tumour involvement of level IV nodes was noted in 5% (2/38) of dissections where lymph nodes were retrieved, but in neither instance was pathological staging altered. There was a significant decrease in the incidence of level IV node retrieval from 47% (28/60) in the first 6 months of audit to 20% (8/40) subsequently. This novel approach to our continuing audit identified quality control criteria for this procedure in our unit and suggested that audit of this kind benefits training.

Breast Neoplasms↗

The comparison of type of incision for transperitoneal abdominal aortic surgery based on postoperative respiratory complications and morbidity.

Equal access to the abdominal aorta can be attained through midline and transverse abdominal incisions. The surgical literature suggests that transverse incisions cause less postoperative pain and morbidity. Fifty patients (10 females and 40 males, mean age 67 years) undergoing abdominal aortic surgery were randomised to a midline (n = 25) or transverse (n = 25) incision. All patients were evaluated preoperatively and postoperatively for seven days. Changes in pulmonary function (FVC and FEV1), time to open and close the incision, analgesia used (morphine mg/kg/h), clinical or X-ray evidence of chest infection, and the duration of ICU stay were recorded. In the transverse group there was a reduction in the incidence of chest complications (20% vs. 28%, p = ns) and these incisions took longer to open (13.9 +/- 4.6 vs. 9.9 +/- 5.1, p < 0.05), but overall there was no significant difference between any other parameter in the two groups. Our results show no statistically significant difference in morbidity or analgesia consumption following transverse or midline abdominal incisions and we conclude that the type of incision used can be left to the surgeon's preference.

Aged↗

Polar map or novel three-dimensional display technique for the improved detection of inferior wall myocardial infarction using tomographic radionuclide ventriculography.

Tomographic radionuclide ventriculography has the potential to be a significant improvement over conventional planar imaging. Although tomographic imaging can now be performed with relative ease, it is little used. This is most probably due to a perceived imbalance between potential clinical benefit and the extra complications of imaging. We investigated this matter by examining a series of 30 patients with isolated inferior or anterior myocardial infarction, identified by cardiac catheterization. Using either radionuclide imaging method, a significant wall motion abnormality was defined as matching (and appropriately located) phase and amplitude values outwith of two standard deviations from control values. These values were obtained from a series of 25 controls and represent construction values used to create a conventional polar map display. Overall detection rates for anterior myocardial infarction were 93 and 100% for planar and tomographic imaging, respectively (ns). For inferior myocardial infarction the rates were 7 and 93%, respectively (p < 0.001). Identical results were found using a novel three-dimensional method of displaying wall motion abnormalities. Tomography is therefore superior to planar imaging for the detection of inferior myocardial infarction but similar to planar imaging for the detection of anterior myocardial infarction.

Cardiac Catheterization↗

Raised levels of antistreptokinase antibody and neutralization titres from 4 days to 54 months after administration of streptokinase or anistreplase.

Streptokinase and anistreplase are antigenic and their administration often leads to antibody formation. These can cause allergic reactions and/or neutralization of streptokinase with resulting suboptimal treatment. Currently, streptokinase re-administration is considered appropriate for up to 5 days and from 1 year after a previous dose. Antistreptokinase antibody and neutralization titres (NT) were measured in three groups of patients to determine if this practice is appropriate: 1. (early)--36 patients whose titres were measured for at least 5 days after thrombolysis; 2. (late)--57 patients who received thrombolysis 12-54 months previously; 3. (controls)--182 consecutive suspected myocardial infarction patients (without previous exposure to thrombolysis). Results were as follows (mean +/- SEM): 1. (early)--the antibody and/or NT were raised by day 4 in 19.4% of the patients. One patient could have neutralized 1.97 million units (MU) of streptokinase by day 4. (Day 4--antibody 1:39 +/- 11, NT 0.19 +/- 0.05 MU; day 5--1:136 +/- 41 and NT 0.7 +/- 0.43 MU respectively.) 2. (late)--23 patients (40%) had either antibody titres > or = 1:160 and/or NT > 1.5 MU. (12-23 months--antibody 1:243 +/- 43, NT 0.63 +/- 0.15 MU; 24-35 months--1:98 +/- 31 and 0.69 +/- 0.22 MU; 36-54 months--1:87 +/- 14 and 0.54 +/- 0.12 MU.) All titres were significantly higher than the controls (antibody 1:25 +/- 3, NT 0.14 +/- 0.01 MU, P < 0.01). After streptokinase or antistreplase, antibodies are raised from 4 days to at least 54 months. It would seem prudent to avoid their re-administration during this time interval.

Anistreplase↗

Hypersensitivity reactions to streptokinase in patients with high pre-treatment antistreptokinase antibody and neutralisation titres.

After streptokinase or antistreplase administration, raised antibody levels can persist for many years, but it is unclear if these antibodies can cause allergic reactions following streptokinase re-administration for myocardial re-infarction. Pretreatment antistreptokinase antibody (AB) and neutralisation titres (NT) were measured in 189 consecutive patients (57 received streptokinase or anistreplase). Seven patients had previous exposure to streptokinase or anistreplase; they had high mean (SEM) antibody titres of 1:801 (332) and neutralisation titres of 3.3 (1.7) million units. The 182 patients without previous thrombolysis had mean (SD) antibody titres of 1:25 (3) and neutralisation titres of 0.14 (0.08) million units; nine patients (4.95%), however, had raised antibody titres of > or = 1:160 and neutralisation titres of > or = 0.3 million units. Of the 15 patients with antibody titres of > or = 1:160, three received streptokinase or anistreplase. Hypersensitivity reactions occurred in all three patients--neutralisation titres 0.48, 1.5 and 1.1 million units respectively. Two became severely hypotensive with systolic pressures of 70 mmHg; one developed a serum sickness-like reaction. Importantly, none of the 54 patients with antibody titres of < 1:160 who received streptokinase or antistreplase reacted adversely to the thrombolytic agents (chi 2 with Yates's correction = 38.71, P < 0.01). High antibody titres are associated with hypersensitivity reactions to streptokinase. This has important implications in reinfarction thrombolysis. In patients whose antistreptokinase antibody titres are likely to be raised the avoidance of streptokinase-related thrombolytic agents should be considered.

Adult↗

Evidence of genetic and phenotypic heterogeneity in the Romano-Ward syndrome.

We report two families with phenotypically different forms of Romano-Ward syndrome. In one family, only five of 18 affected subjects are symptomatic, whereas in the other the proportion is three out of five. The families show distinct ECG morphologies, in addition to QT prolongation. Previous reports have shown genetic linkage either to the HLA locus on chromosome 6 or the Harvey-ras oncogene on chromosome 11. No linkage was found to either locus in the families reported here. The implications of phenotypic and genotypic heterogeneity in Romano-Ward syndrome are discussed in relation to the neurogenic and intrinsic models of pathogenesis.

Chromosomes, Human, Pair 11↗

Transcriptional repression by methylation of CpG.

Methylated DNA in mammals is associated with transcriptional repression and nuclease resistant chromatin. In this review we discuss how these effects may be mediated by proteins that bind to methylated DNA.

Animals↗

Non-methylated islands in fish genomes are GC-poor.

In the vertebrate genomes studied to date the 5' end of many genes are associated with distinctive sequences known as CpG islands. CpG islands have three properties: they are non-methylated; the dinucleotide CpG occurs at the frequency predicted by base composition; and they are GC-rich. Unexpectedly we have found that CpG islands in certain fish only have the first two properties; that is, their GC-content is not elevated compared to bulk genomic DNA. Based on this finding, we speculate that the GC-richness of CpG islands in vertebrates other than fish is a passive consequence of a higher mutation rate in regions of open chromatin under conditions where the nucleotide precursor pools are biased.

Actins↗

Kikuchi's necrotising lymphadenitis.

Three cases of Kikuchi's necrotizing lymphadenitis without granulocytic infiltration presented to the ENT department as cervical lymphadenopathy with neutropaenia. Differential diagnosis from malignant lymphoma was difficult both clinically and histopathologically. Two recovered spontaneously without treatment within three months, one improved initially but was lost to follow-up after one month.

Adult↗

The structure of a subterminal repeated sequence present on many human chromosomes.

All telomeres which have been studied consist of an array of simple G/C rich repeats. Human telomeres were shown to share sequence similarity with those of lower eukaryotes by cross-hybridization and human telomeric sequences have been cloned by complementation of telomere function in yeast. Analysis of human telomeric sequences cloned in this way is described here. The terminal part of the cloned human telomeric DNA consists of an array of simple repeats, principally of the sequence TTAGGG and derivatives. The very terminal part consists of yeast-type telomeric repeats which suggests that the human telomeric sequences have acted as a primer for the addition of additional telomeric repeats in the yeast. Subterminal sequences are shared between a number of clones and in situ data shows that these subterminal sequences are present at several different chromosomal ends. Related sequences are present at internal as well as telomeric positions. Differences in the hybridization patterns of subterminal sequences in somatic compared to germ-line tissues are described which indicate differential modification of these sequences during development.

Base Composition↗