Binding specificity of serum amyloid P component for the pyruvate acetal of galactose.

Serum amyloid P component (SAP) is a normal plasma protein that is of interest because of its presence in amyloid deposits, its presence in normal human glomerular basement membrane, and its stable evolutionary conservation. It has calcium-dependent ligand-binding specificity for amyloid fibrils, fibronectin (Fn), C4-binding protein (C4bp), and agarose. Although the binding to agarose, a linear galactan hydrocolloid derived from some marine algae, is unlikely per se to be related to the physiological function of SAP, it does provide a model system in which to explore the precise ligand requirements of SAP. We report here that the amount of SAP from human, mouse, and plaice (Pleuronectes platessa L.) serum able to bind to agarose from different sources reflect precisely their pyruvate content. Methylation with diazomethane of the carboxyl groups in the pyruvate moiety of agarose completely abolishes SAP binding to agarose. The pyruvate in agarose exists as the 4,6-pyruvate acetal of beta-D-galactopyranose. We have therefore synthesized this galactoside, using a novel procedure, established its structure by analysis of its nuclear magnetic resonance spectra, and shown that it completely inhibits all known calcium-dependent binding reactions of SAP. The R isomer of the cyclic acetal, methyl 4,6-O-(1-carboxyethylidene)-beta-D-galactopyranoside (MO beta DG) was effective at millimolar concentration and was more potent than its noncyclic analogue, while pyruvate, D-galactose, and methyl beta-D-galactopyranoside were without effect. The autologous protein ligands of SAP presumably, therefore express a structural determinant(s) that stereochemically resembles MO beta DG. Availability of this specific, well-characterized, low molecular weight ligand for SAP should facilitate further investigation of the function of SAP and its role in physiological and pathophysiological processes.

Calcium-dependent aggregation of human serum amyloid P component. Inhibition by the cyclic 4,6-pyruvate acetal of galactose.

Serum amyloid P component is a normal plasma glycoprotein which is the precursor of amyloid P component, a minor but universal constituent of amyloid deposits. When isolated human P component is exposed to free ionised Ca2+ it aggregates and precipitates. This phenomenon is completely inhibited by the presence of 10(-4)-10(-2) M methyl 4,6-O-(1-carboxyethylidene)-beta-D-galactopyranoside, a recently synthesised specific ligand for amyloid P component. This observation suggests that the autoaggregation of human amyloid P component involves the Ca2+ dependent specific ligand binding property of P component, but does not distinguish between receptor-site-mediated and allosteric mechanisms.

Effect of cardiopulmonary bypass on circulating concentrations of leucocyte elastase and free radical activity.

Circulating concentrations of leucocyte elastase and free radical activity were measured in 11 adults undergoing cardiopulmonary bypass. In all patients the bypass procedure was associated with pronounced changes in plasma elastase concentrations, and peak enzyme concentrations correlated closely with the duration of bypass (r = 0.91, p less than 0.001). Serial measurement of octadeca-9, 11-dienoic acid, a non-peroxide marker of free radical activity, showed significant changes only in the plasma free fatty acid fraction, suggesting a direct relation to the action of heparin rather than to the bypass procedure as such. These studies support the hypothesis that neutrophil activation plays a central role in the organ dysfunction that may complicate cardiopulmonary bypass and suggest that elastase release rather than free radical generation may be the appropriate marker of the event.

Indicators of free radical activity in patients developing radiation pneumonitis.

PURPOSE: Radiation pneumonitis is thought to occur as the result of excess free radical generation following radiotherapy. Various in vitro studies have shown that large doses of irradiation can cause membrane lipid peroxidation and the oxidation of protein sulphuryl groups. We, therefore, studied two circulating markers of lipid peroxidation and an indicator of "catalytic iron" (potentially available iron to catalyze the generation of free radicals) in patients undergoing radiotherapy. METHODS AND MATERIALS: The 9,11 diene conjugate of 9,12 linoleic acid, expressed as their molar ratio (percentage molar ratio (MR)) and thiobarbituric acid reactive acid-substances (TBARS), as well as levels of circulating desferrioxamine-chelatable iron assay, were assayed. Serial blood samples were taken over a 3-month period in 25 patients with inoperable nonsmall cell lung cancer. RESULTS: Ten patients developed radiation pneumonitis. The patients who developed pneumonitis showed a tendency for the serum percentage molar ratio to increase after a week. The change in the percentage molar ratio between Time 0 and 1 week of radiotherapy was significantly higher in the group that subsequently developed pneumonitis compared to the group that did not (p = 0.002). The initial serum TBARS levels in patients were not significantly elevated compared to controls and there was no difference in the serum TBARS levels in the pneumonitis and nonpneumonitis groups throughout the study period. After 1 week of radiotherapy the group that subsequently developed pneumonitis had a significantly higher level of desferrioxamine-chelatable iron (DFx-iron) compared with the nonpneumonitis group (p = 0.05). CONCLUSION: These data suggest that both the percentage MR and DFx-iron appear to reflect an increased susceptibility to develop radiation pneumonitis and after 1 week of radiotherapy they indicate patients who are likely to subsequently develop pneumonitis. Hence, these indicators could indicate the group of patients that could benefit from intervention therapies with antioxidants.

Bronchoscopic insertion of Gianturco stents for the palliation of malignant lung disease: 10 year experience.

Malignant large airway obstruction is life threatening and may not be amenable to urgent radiotherapy. Palliative airway stenting is difficult and traditionally carried out under general anaesthesia and fluoroscopy. We have shown that self expanding Gianturco metal stents can be placed under local anaesthesia using fibreoptic bronchoscopy and direct vision for the treatment of malignant airway tumours, and report our 10 year experience. All referrals for stenting referred to our unit between 1990 and 1999 were included, looking for histological type, number and site of stents, complications of the procedure, other interventions, and survival. One hundred and sixty two patients (average age 64 years, (range 21-89)) had 307 stents inserted during 167 procedures (144 primary lung tumours, 18 secondary malignancy). There were no operative deaths, but three patients developed a pneumothorax, one requiring intercostal drain insertion. Average survival following stent insertion was less for primary lung cancer than for secondary disease (103 vs. 431 days, P<0.001). There were no excess complications in a subgroup of 64 patients treated locally by oncologists, even when stenting was the primary procedure. This technique is useful in palliating life threatening airway obstruction, particularly for secondary cancer, and can be used in any centre undertaking fibreoptic bronchoscopy.

The use of expandable metal stents for large airway obstruction in older patients.

OBJECTIVE: To review the indications, management, and outcome of 30 older patients who had expandable metal stents inserted for large airway obstruction. DESIGN: Information was collected retrospectively from case notes about presentation, radiographic appearances, pulmonary function, including arterial oxygen tension, and histology. Survival data were collected by reviewing hospital or General Practice records. MEASUREMENTS: Spirometry, peak expiratory flow rate, and blood gases were recorded before and after stent insertion. MAIN RESULTS: There was a significant improvement in the patient's mean forced expiratory volume in 1-second (FEV1) and mean peak expiratory flow rate (PEFR). The arterial oxygen tension (pO2) increased from 8.6 Kpa to 10.6 Kpa. The mean length of survival for the whole group was just under 5 months. CONCLUSIONS: Airway stenting for obstruction provides palliative and functional benefits in these severely disabled patients and a consequent improvement in quality of remaining life.

Plasma leucocyte elastase concentrations in smokers.

The associations between cigarette smoking, plasma leucocyte elastase concentration, peripheral leucocyte count and FEV1 were examined in 148 men, 72 of whom were current cigarette smokers, 40 of whom were ex-smokers, and 36 who had never smoked. All men were part of a long-term survey. Smokers had significantly higher plasma leucocyte elastase concentrations than ex-smokers or those who had never smoked. Mean current FEV1 was lower, and the annual decline in FEV1 in the preceding 10 years was faster in smokers than the other two groups. A few smokers had slight increases in serum C-reactive protein concentrations. Although peripheral blood leucocyte counts were higher in smokers than in non-smokers or ex-smokers, no association was found in any of the three groups of men between plasma elastase concentration and peripheral leucocyte count, nor between either of these two variables and annual decline in FEV1 or current level of FEV1. There was also no relation between plasma elastase concentration and reported daily cigarette consumption or mixed expired carbon monoxide in smokers. The results indicate that some male smokers have increased in vivo release of elastase from peripheral blood neutrophils at a time when there is no evidence of acute infection. Because leucocyte elastase is a strong candidate for pulmonary tissue damage, further studies of the mechanisms that increase plasma concentrations are indicated.

Serum C-reactive protein concentration in the management of infection in patients treated by continuous ambulatory peritoneal dialysis.

In a prospective study over 21 months, serum C-reactive protein (CRP) concentration was measured serially in 39 consecutive patients undergoing continuous ambulatory peritoneal dialysis. All patients with peritonitis mounted a CRP response, and the height of the response correlated well with the severity and extent of the peritoneal damage. Patients who recovered uneventfully after antimicrobial treatment showed a prompt fall in CRP from its peak value towards normal. In contrast, each patient in whom the serum CRP value remained raised after antimicrobial treatment had a complicated course. During routine outpatient follow up the serum CRP value remained within the normal range in the absence of intercurrent complications. These results, together with the commercial availability of rapid and precise assays for CRP, indicate that serial CRP measurements may be useful in monitoring the efficacy of antimicrobial treatment during episodes of peritonitis and in the recognition of intercurrent complications in patients undergoing continuous ambulatory peritoneal dialysis.

Diaphragmatic plication for unilateral diaphragmatic paralysis: a 10-year experience.

Unilateral paralysis of the diaphragm due to nonmalignant disease is an uncommon disorder previously thought to have benign implications. Some patients, however, experience dyspnea and orthopnea with impairment of pulmonary function. Unilateral diaphragmatic plication was performed on 17 patients (16 men and 1 woman with a mean age of 53.7 years [range, 28 to 74 years]) during the last 10 years. Preoperatively each patient was shown to have paradoxical movement of the paralyzed diaphragm on sniffing and to have a reduction in forced vital capacity and lung volumes. These reductions were greater when the patient was in the supine position. All patients had moderate hypoxemia (mean arterial oxygen tension, 73.1 +/- 10.9 mm Hg). Plication was performed by imbricating the diaphragm in layers through a thoracotomy incision. After plication, all patients showed both subjective and objective improvement. Six patients were reassessed 5 or more years after plication (range, 5 to 7 years), and the improvement was maintained. Diaphragmatic plication is a safe and effective procedure for adult patients with dyspnea due to unilateral diaphragmatic paralysis; furthermore, the initial improvement is maintained.

Serum octadeca-9,11 dienoic acid--an assay of free radical activity or a result of bacterial production?

The diene conjugated linoleic acid isomer is currently used as an assay of free radical activity, but recent studies have cast doubt on the specificity of the assay. Therefore, 180 strains of common bacterial lung pathogens were studied to determine whether they could produce the diene conjugated isomer of linoleic acid in vitro. The various strains were grown in tissue culture fluid spiked with linoleic acid. Concentrations of the diene conjugated 18:2 [9,11] linoleic acid isomer and the parent compound, 18:2 [9,12] linoleic acid were then determined using a high performance liquid chromatography method. The percentage molar ratio of these two isomers was found to be significantly elevated in 12.8% of all bacterial strains examined. In contrast the thiobarbituric acid reactivity, a non-specific measure of lipid peroxidation, was not elevated in any of the strains incubated in an identical fashion. These results suggest that the diene conjugated linoleic assay may not be a reliable marker of the free radical processes in the lung in the presence of certain bacterial infections.

Differential free-radical activity after successful and unsuccessful thrombolytic reperfusion in acute myocardial infarction.

BACKGROUND: Free-radical generation after successful thrombolysis in acute myocardial infarction may jeopardize ischaemic but viable myocardium, thus limiting the optimal benefits of reperfusion. METHODS: Circulating free-radical activity was assessed in 25 consecutive patients with acute myocardial infarction. Those who successfully reperfused (Group A) were compared with those who did not (Group B). We also compared patients who had or had not developed Q waves and patients with and without previous angina or myocardial infarction. All patients presented within 6 h of the onset of chest pain and received standard intravenous streptokinase therapy. Free-radical activity in serial serum samples collected over 72 h was measured using the percentage molar ratio (PMR) of the concentrations of 9,11-linoleic acid to 9,12-linoleic acid, and malonaldehyde concentration. RESULTS: Throughout the study period Group A (n = 11) showed significantly greater change in serum PMR and malonaldehyde levels compared with Group B (n = 14) (P < 0.01). PMR differences between the two groups were most pronounced at 3 and 12 h (P < 0.001). Patients with non-Q-wave myocardial infarction (n = 5) showed significantly greater changes in serum PMR and malonaldehyde levels (P < 0.01) compared with those with Q-wave infarction (n = 20). A history of previous infarction or angina had no apparent effects on the changes in serum free-radical activity. CONCLUSIONS: Successful early reperfusion and non-Q-wave myocardial infarction are both associated with a significantly greater increase in the levels of markers of serum free-radical activity immediately after infarction. The results support present concepts of free-radical-mediated reperfusion injury. Use of these assays may identify those patients who may be at risk from free-radical-mediated reperfusion injury.

Nocturnal oxygen desaturation in patients using long-term oxygen therapy for chronic airflow limitation.

Nocturnal oxygen desaturation in patients receiving long-term oxygen therapy is described despite adequate daytime oxygenation (PaO2 greater than 8 kPa). Domiciliary oximetry overnight was performed on ten patients receiving long-term oxygen treatment for chronic airflow limitation: six patients were well saturated throughout the night with a fall in SaO2 to below 90% for only 1% of the monitoring time; four showed significant desaturation with a fall in SaO2 to below 90% for periods of 15-47% of the monitoring time.

Factors influencing the compliance of patients using oxygen concentrators for long-term home oxygen therapy.

A previous study in the Liverpool district on patients receiving long term oxygen treatment using a domiciliary oxygen concentrator showed that only 55% were both using oxygen therapy correctly and had stopped smoking. To try and identify which factors influence patient behaviour, all 55 patients in this district receiving long-term oxygen therapy for hypoxaemic chronic airflow limitation were studied. We found that those with more symptoms were more likely to comply with this therapy. The prescription of a concentrator on the advice of a hospital physician did not improve on the compliance rates attained in those patients assessed by the general practitioner alone.

Twenty-four-hour tracheal pH monitoring--a simple and non-hazardous investigation.

Prolonged oesophageal pH monitoring is commonly used in the investigation of gastro-oesophageal reflux. In contrast, tracheal pH monitoring is virtually unknown. We report a simple technique of measuring tracheal pH where the pH probe is inserted under local anaesthetic and can be left in position for 24 h to allow prolonged monitoring. Ten control individuals were studied. All completed the study without complication. One patient with mixed connective tissue disease, failed hiatal hernia repair and subsequent recurrent aspiration pneumonia was studied, on and off ranitidine, using simultaneous tracheal and oesophageal pH monitoring. This method showed evidence of gastro-oesophageal reflux and tracheal aspiration off treatment. When repeated with the patient taking ranitidine, the frequency of significant gastro-oesophageal reflux was reduced and no episodes of tracheal acid aspiration were recorded. Prolonged tracheal pH monitoring is a simple and non-hazardous technique. It is sensitive in detecting tracheal aspiration and may be more sensitive than pre-existing radiolabelled isotope techniques.

Recurrence of circulating anti-glomerular basement membrane antibody three years after immunosuppressive treatment and plasma exchange.

A patient with auto-antibody mediated Goodpasture's syndrome was successfully treated with cytotoxic drugs, steroids and plasma exchange. After an absence of three years, circulating anti-glomerular basement membrane antibodies reappeared, and linear IgG staining of the glomeruli was shown by immunofluorescent studies. Renal function did not change and there was no evidence of pulmonary hemorrhage. Antibody levels then fell spontaneously over the succeeding 18 months.

Objective monitoring of activity in Wegener's granulomatosis by measurement of serum C-reactive protein concentration.

Serial measurements of the serum concentration of C-reactive protein were made in 38 patients with Wegener's granulomatosis during a period of 6 years. The concentration was always elevated when the disease was active, even in patients receiving immunosuppressive treatment, and fell rapidly in association with clinical remission induced by immunosuppression. During periods of complete remission, in the absence of any intercurrent condition, the value remained within the normal range. The correlation between C-reactive protein level and disease activity was much closer than that between erythrocyte sedimentation rate and disease activity. These results indicate that serial measurement of the serum C-reactive protein fills the urgent need for an objective index of the activity of Wegener's granulomatosis and its response to therapy.

Left main coronary artery stenosis: experience of 93 patients.

The clinical and angiographic findings in 93 consecutive cases of significant (greater than or equal to 50%) obstruction of the left main coronary artery were studied. This lesion was found in 6.85% of patients who underwent coronary arteriography. 93.5% of patients had presented with angina pectoris, of which 28% had unstable angina. There was one catheter-related death. Follow-up data were available in 90 cases, of which 23 were treated medically. Poor left ventricular function and significant right coronary artery disease adversely influenced the outcome in this group. 67 patients had aortocoronary saphenous vein bypass grafting. The operative mortality was 18% overall, but 36% in those undergoing emergency surgery (within 48 hours of catheterisation). Poor left ventricular function and electrocardiographic evidence of previous inferior myocardial infarction were associated with poor operative survival. The 55 survivors of surgery had an excellent prognosis with an annual attrition rate of 4% over two year follow-up period. 87% were asymptomatic at follow-up.

Prescription of oxygen concentrators for long term oxygen treatment: reassessment in one district.

When oxygen concentrators became available on form FP10 in 1985 the Department of Health and Social Security issued clear guidelines for their prescription for long term treatment. Reassessment of those patients prescribed a concentrator in one district showed that 29 out of 61 patients did not fulfil these criteria. Furthermore, in only 28 cases was the daily use of the machine appropriate, though this did not reflect poor patient cooperation but was a result of inadequate prescribing instructions. In addition, 12 out of 54 patients continued to smoke. Overall, in only 18 of the 61 cases was both the prescription appropriate and the concentrator properly used. These results suggest a need for better cooperation between general practitioner and hospital in the initial assessment of patients for long term oxygen treatment and better education of both doctor and patient in the use of oxygen concentrators.