Biomedical subjects
Publications and source records attributed to A Platts.
Complications associated with the use of the Swan-Ganz catheters including coiling and knotting of the catheter in the central venous system or in the chambers of the heart, often with disastrous consequences. We report a case of knotting of a Swan-Ganz catheter in the superior vena cava which necessitated surgical removal via the right internal jugular vein.
The objectives of this study were (i) to identify patterns of angiographic disease in scleroderma patients with and without other vascular risk factors and (ii) to define patients with scleroderma in whom angiography and angioplasty is useful. The records of 26 patients with scleroderma who underwent angiography and angioplasty over an 8-year period were reviewed. Angiographic disease patterns were assessed using a modified Brewster classification. Angiography of the upper limb demonstrated distal disease alone in 86% of patients, both with and without other vascular risk factors such as smoking. In the lower limb there was a highly significant association between the presence of other vascular risk factors and macrovascular disease potentially amenable to angioplasty, and conversely between the absence of other vascular risk factors and distal disease in the lower limb. Good early but poor late clinical results were achieved in three of five patients who underwent angioplasty. Angiography of the upper limb is likely to demonstrate distal disease alone, and angiography and angioplasty of the lower limb may be useful only if other vascular risk factors are present.
OBJECT: The aim of this study was to determine if radiological features could be used to predict outcome in patients with cervical spondylotic myelopathy (CSM). METHODS: The authors studied 69 patients consecutively referred to The National Hospital, Queen Square, for decompressive surgery. Data obtained from preoperative cervical spine magnetic resonance (MR) imaging studies were each analyzed on two separate occasions by two blinded radiologists. The parameters determined were signal change and the presence and severity of compression. Clinical outcome was determined by pre- and postoperative timed walks, as well as by evaluation of myelopathy disability index scores, Ranawat classification, and Nurick grades. There was good inter- and intraobserver reliability for determination of radiological data. A significant relationship was found between MR imaging signal change and surgery-related outcome, as reflected by improvement in walking parameters; however, this was confounded by the fact that signal change also related to preoperative walking parameters, and those patients for whom preoperative walking function was worse experienced greater functional improvement in walking postoperatively. The relationships between ambulatory-related data and severity or extent of spinal cord compression were less marked. CONCLUSIONS: Cervical cord compression and intrinsic MR imaging signal change correlate with clinical severity, and, in this population, the presence of signal change was correlated with better surgery-related outcome. However, confounding factors and the lack of strong correlation indicate that these radiological measurements are insufficient to be used as a reliable tool for predicting surgery-related benefits in individual patients.
BACKGROUND: Thrombolysis could be a major step forward in the treatment of acute ischaemic stroke. Early treatment is essential to maximize therapeutic benefit. Imaging by computed tomography (CT) or magnetic resonance imaging is mandatory to exclude haemorrhagic stroke before initiation of therapy. Thrombelastography (TEG), a test of global haemostasis, produces a characteristic tracing over 15-30 min. The potential of TEG to differentiate patients with ischaemic from haemorrhagic stroke was investigated. METHODS: Fifteen patients with a clinical diagnosis of acute stroke were studied. Fibrinogen levels and lipid profiles were measured, and CT of the brain, coagulation screens and TEG were performed. The CT scans were interpreted by a single radiologist. TEG data were classified as normal (index less than 2), hypercoagulable (index 2-3) or profoundly hypercoagulable (index greater than 3). RESULTS: There was no correlation between any of the parameters studied other than TEG with CT findings. Both patients with a haemorrhagic stroke showed normal findings on TEG. Eleven of the 12 patients with ischaemic stroke were hypercoagulable or profoundly hypercoagulable. CONCLUSION: TEG is capable of differentiating haemorrhagic from ischaemic stroke. It has the potential to target thrombolytic therapy for those patients most likely to benefit.
BACKGROUND: Inferior vena caval filters are a recognized intervention for recurrent pulmonary embolism (PE). Filter utilization in the UK is considerably less than in Europe; this may partly be due to omission of referral of appropriate patients. METHODS: A cohort with the prospect of benefit from caval filter insertion was identified by retrospective study of inpatients who died within 30 days of a positive ventilation-perfusion (V/Q) scan over 2 years. The number of actively managed patients in this group who fulfilled the recognized criteria for caval filter insertion was determined. RESULTS: Fifty-two of 606 patients died within 30 days of scanning. Information was available on 38 (73 per cent) of 52 who had 39 scans (14 positive, 22 negative, three indeterminate). Six of 14 patients (two men and four women, aged 46-84 years) with a positive scan had strong indications for caval filter deployment including contraindication to anticoagulation (three), recurrent PE despite adequate anticoagulation (two) and complications arising from anticoagulation (one). All six died following continuing embolism or complications from anticoagulation. CONCLUSION: Six of 14 patients who died following acute PE required caval filtration but were not offered this intervention. Failure to refer patients who would benefit from filtration may partially account for the disparity in utilization of caval filters between the UK and Europe. Furthermore, because of the choice of death as outcome marker, this study underestimated the value of caval filter utilization.
Transcatheter arterial embolization (TCAE) is a well recognized radiological technique that has been used for over 25 years. It is a method of diminishing blood flow through selected vessels by inserting haemostatic material under angiographic control. The procedure is performed under local anaesthetic through a femoral or, occasionally, an axillary approach. We present our experience of the use of TCAE in the management of pain and haemorrhage in three hospice inpatients in whom other options had been exhausted. The use of TCAE as a technique for the palliation of these symptoms in the hospice setting is discussed.
The mode of cytotoxic action employed by cytolytic lymphocytes remains unclear, with the possibility of several mechanisms being utilized dependent upon the activation state of the effector cell. In this work, the induction of apoptosis in target cells by 'killer' lymphocytes at differing states of activation has been studied. Although the cytotoxicity of natural killer (NK) cells and recombinant human interleukin-2 (rhIL-2) or interferon-alpha (IFN-alpha)-activated effector cells, against NK-sensitive target cells, was high, their cytotoxic action appeared to be mediated via differing pathways. Effector cells activated short term (4 hr) with rhIL-2 and those mediating rhIL-2 lymphokine-activated killer (LAK) activity after long-term (4 day) activation were found to induce the formation of sodium dodecyl sulphate (SDS)-insoluble apoptotic bodies in NK-sensitive target cells, as well as increasing the level of activity of the apoptosis related enzyme tissue transglutaminase, thus suggesting the induction of the apoptotic pathway as a means of effecting target cell death. Non-activated and short-term (4 hr) IFN-alpha-activated effector cells did not appear to utilize this pathway in the target cell as their means of cytotoxicity. Effector cells showing LAK activity were also cytotoxic towards NK-insensitive cells, and this cytotoxicity again appeared to be mediated via the apoptotic pathway.
A patient with a traumatic occult spinal pseudomeningocele is presented. The possible etiology and the use of a lumboperitoneal shunt in this situation are discussed.
This study aimed to test the hypothesis that the use of fine rather than larger calibre needles for myelography reduces the incidence of post-procedural headache. 160 patients were randomized in a prospective controlled trial of 22 gauge versus 26 gauge needles. The incidence and overall severity of headache as measured at 1, 4 and 21 days after myelography was not significantly different in the two groups.
Caval compression secondary to hypertrophy of the caudate lobe is a well known complication of Budd-Chiari syndrome. This paper describes the use of an expandable metal stent to overcome external caval compression. Meso-caval shunting was subsequently performed with a good end result.
The cranial computed tomographic (CT) scans reported as showing metastatic disease in patients with malignant melanoma (MM) seen at the Westminster Hospital over a 5 year period were reviewed. Ninety-eight patients with intracranial metastatic MM were identified. Twelve had an initial scan which was reported as normal and particular attention was given to these to see if, in retrospect, any early features of metastatic disease were discernible. Fifty-eight cases showed the "typical" features of intracranial MM; the remainder were unusual in appearance, behavior, or site. Radiological regression was shown in only seven cases on follow-up scans; all but one of these patients had one or two large metastases. No significant lesion was thought to have been missed on a scan after the administration of intravenous contrast medium, but the lesions of three patients were difficult to discern on plain scans. Thus when MM metastasis is suspected, the use of the contrast-only scan is advocated.
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The calmodulin antagonist W7 and 4 of its analogues were examined for their ability to inhibit human NK cell mediated cytotoxicity. With the exception of one of these compounds, which is extremely hydrophobic, there was a good correlation between the ability of drugs to inhibit human NK antitumour cytotoxicity and calmodulin-dependent phosphodiesterase activity in vitro. The most potent of the compounds, 5-iodo-1-C8, an analogue of W7, has an IC50 of 3 microM upon biological and biochemical assay. This particular compound is both more potent and specific than the parent compound W7, is non-toxic to cells over the range used and is also capable of inhibiting the biological activity of NK cells upon pre-treatment of the effector cells, inferring the mechanism of NK cytotoxicity to be calmodulin dependent.
Eighty-seven patients with malignant obstruction of the biliary tract from three centres and deemed unsuitable for surgery underwent insertion of the 'Carey-Coons' transhepatic endoprosthesis. It was successfully introduced in all, with early relief of cholestasis in 97%. The 30 day mortality rate was 11.5%, which is lower than reported in series using different endoprostheses. Two fifths of patients had complications, especially cholangitis. Despite its ease of insertion the design of the endoprosthesis may be related to the high incidence of cholangitis and to formation of biliary sludge and occlusion found in follow up. Although the anchoring threads prevented migration, they may have played a role in infection at the skin entry site in four patients and in tumour seeding to the skin in a further two. Still further improvements in endoprosthesis design are desirable.
Normal human peripheral blood mononuclear cells (PBMC) and leukaemic cell lines (three of human and one of gibbon origin) were found to contain similar levels of calmodulin (CaM) when expressed relative to the total cell protein. Two of the cell lines examined further were found to contain much higher amounts of CaM per cell (up to 5-fold) than PBMC but this was readily explained by their much greater cell size. Variations in CaM levels were noted during culture of both PBMC and leukaemic cells which were apparently independent of the percentage of cells undergoing active division in these cultures. These results do not support the contention that transformed cells contain a higher proportion of CaM than normal cells.
This study was instituted to determine the mechanism of enhanced natural killer (NK) lymphocyte activity during surgery. Natural cytotoxicity of whole blood to K562 target cells was assayed before anesthesia and during anesthesia and surgery in patients with benign and malignant gastrointestinal disease. Those patients with benign conditions and localized primary tumors showed enhanced NK lymphocyte cytotoxicity during surgery (p less than 0.025 and p less than 0.0025, respectively) but not patients with disseminated tumors. In patients with localized tumors, enhancement of NK lymphocyte cytotoxicity was an interferon-independent phenomenon but appeared to be related to a significant rise in the percentage of cells bearing the Leu 7 monoclonal antibody marker for NK cells (p less than 0.02). Exogenous leukocyte interferon caused further enhancement of NK cytotoxicity in patients with benign disease and some cancer patients. Enhancement of NK lymphocyte activity during surgery may be of significance in reducing tumor metastases by stimulation of natural cytotoxic mechanisms to circulating tumor emboli.
Due to the current interest in natural killer (NK) cells as a host defence mechanism against neoplasia, we have investigated the susceptibility of short-term cultures of human ocular melanoma cells to spontaneous and interferon (IFN)-augmented natural cytotoxicity. Cultures of ocular melanoma cells were readily established and identified as bipolar and multipolar pigmented melanoma cells. In short-term cytotoxicity assays these cell lines demonstrated a weak susceptibility to spontaneous human PBL natural cytotoxicity, and increased killing was observed using IFN-augmented cytotoxic effector cells. These findings may be pertinent in relation to the role of NK cells in vivo.
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