Macrophages, neutrophils and tumour necrosis factor-alpha expression in bronchiectatic airways in vivo

Bronchiectasis is increasingly being recognized as an inflammatory condition of the airways in which pathological permanent dilation occurs. We have obtained endobronchial biopsies in 14 patients with stable bronchiectasis and 15 control subjects. Airway neutrophils, macrophages and tumour necrosis factor-alpha (TNFalpha)-positive cells were stained with monoclonal antibodies and the densities of positive cells in the lamina propria were determined by using a computer image analyser. There was significantly higher neutrophil, macrophage and TNFalpha-positive cell densities in the lamina propria of bronchiectatic than control airways (P < 0.001, P < 0.001 and P=0.0002, respectively). Airway neutrophil density in bronchiectasis but not in controls, correlated with TNFalpha-positive cell density (r=0.71, P=0.004). A significant correlation between airway macrophage and TNFalpha-positive cell densities was demonstrated in both control and bronchiectatic airways (r=0.63, P=0.016 and r=0.60, P=0.02 respectively). Neutrophil density negatively correlated with per cent forced vital capacity (FVC%) predicted among patients with bronchiectasis (r=-0.53, P=0.04). Bronchiectasis patients who were regular sputum producers had a significantly higher macrophage, but not neutrophil density than their counterparts (P=0.02 and P=0.48 respectively). Our original findings suggest that airway macrophages could contribute to neutrophil influx into airway walls through their production of TNFalpha and therefore play an important role in the pathogenesis of bronchiectasis.

Effects of dexamethasone on the expression of Fas molecules and apoptosis of lymphocytes in patients with systemic lupus erythematosus

Previous studies have shown that the autoimmune phenomenon could be caused by defective apoptosis of autoreactive lymphocytes. Corticosteroids used for treatment of systemic lupus erythematosus (SLE) are potent apoptosis inducers. We examined dexamethasone (DEX)-induced apoptosis and Fas expression in peripheral blood lymphocytes of SLE patients and normal subjects. Peripheral blood lymphocytes were obtained from 40 SLE patients and 18 sex- and age-matched control subjects. Percentages of apoptosis and expression of Fas molecule in lymphocytes were assessed by flow cytometry. Fas expression in lymphocytes treated with or without DEX was significantly higher in SLE patients than normal controls [median (interquartile range) of mean fluorescence intensity without DEX: 74.9 (50.7-98.0) vs 20.0 (17.7-25.0), p < 0.001; with DEX: 77.9 (56.0-130.5) vs 20.5 (18.6-24.7), p<0.001]. DEX (0.1-5 microM) could also induce apoptosis of lymphocytes from SLE and control subjects in a dose-dependent manner. Elevation of apoptotic susceptibility was more prominent in DEX-treated SLE lymphocytes [33.9% (24.7-37.5%) vs 19.6% (13.6-26.1 %), p = 0.003]. The higher apoptotic susceptibility of SLE lymphocytes upon DEX treatment in vitro may be related, at least partly, to the pharmacological action of corticosteroids.

Respiratory ciliary function in bone marrow recipients

Bone marrow transplantation (BMT) recipients, particularly those with chronic graft-versus-host disease (GVHD), suffer from respiratory tract problems, including bronchiolitis obliterans (BO) and recurrent lower respiratory tract infections. Minute cilia beat continuously on the surface of respiratory mucosa, and this beating maintains the sterility of the lower respiratory tract. Dysfunction of respiratory cilia could lead to development of recurrent respiratory tract infections, which are also features of BMT recipients, although ciliary function has not been systematically studied among these subjects. We have, therefore, investigated the ciliary beat frequency (CBF) of 36 Chinese patients who had undergone allogeneic BMT. The CBF was significantly lower in the BMT group compared to controls (P < 0.001). The reduction in CBF was more severe in patients with cGVHD and BO compared with their counterparts (P = 0.048 and P = 0.077, respectively). There was a correlation between CBF with forced expiratory flow rate FEF (P = 0.024) and forced expiratory volume FEV (P = 0.044). We conclude that abnormal ciliary clearance is a common feature after allogeneic BMT, particularly among patients with BO and cGVHD. Further studies are indicated to evaluate this important phenomenon, which could be an important cause of the susceptibility for BMT recipients to respiratory infections.

Pulmonary sequelae of treatment for breast cancer: a prospective study

PURPOSE

To prospectively study the effects of loco-regional radiotherapy in women with breast cancer.

METHODS AND MATERIALS

Thirty consecutive patients with breast resection underwent clinical, lung function, radiographic, and thoracic high-resolution computed tomography evaluation before and at 1, 3, 6, and 12 months after adjuvant radiotherapy. Chemotherapy was also administered to 15 patients.

RESULTS

Nineteen patients reported mild respiratory symptoms at 1 month, which resolved completely at 6 months after radiotherapy. Opacities were present on 80% of chest radiographs and in all patients on high-resolution computed tomography by 3 months. These opacities became compact and persisted on high-resolution computed tomography at 12 months. Lung function indices, including FEV1, FVC, TLC, and DLCO, progressively declined after radiotherapy, and was irreversible at 12 months (p < 0.05). Patients who received chemotherapy did not have significantly different lung function indices compared with their counterparts at all time points (p > 0.05).

CONCLUSIONS

Our results have shown that adjuvant loco-regional radiotherapy, a common practice in breast cancer treatment, is associated with irreversible reduction in lung function parameters. These changes are accompanied by radiological evidence of persistent lung injury. Further studies should be performed to evaluate the incidence and long-term pulmonary sequelae of current treatment for breast cancer.

Increasing use of inhaled steroids associated with declining asthma mortality

Increasing worldwide asthma prevalence and mortality has led to greater advocacy of inhaled agents, especially steroids. To determine whether corresponding drug usage trends had ensued locally, wholesale data (expressed as defined daily doses (DDDs)/1000 inhabitants/day) were compared for inclusive periods 1984-1986 and 1992-1994. Whereas absolute usage of anti-asthmatics increased by 79%, proportional inhaled usage increased markedly, especially of steroids (571%) and in hospitals. An odds ratio trend analysis revealed asthma mortality from 1992 onward had declined, particularly in males (p < 0.001). In Hong Kong, despite increasing asthma prevalence, more intensive use of anti-asthmatic drugs (especially inhaled steroids) was associated with declining asthma mortality.

Genomic imprinting and cancer; new paradigms in the genetics of neoplasia

The role of epigenetic modification of gene expression is becoming increasingly important in how we understand the loss of tumour suppressor gene function in a variety of tumours and tumour predisposing syndromes. This review explores the importance of epimutation in Beckwith-Wiedemann syndrome and Wilms' tumour and focuses on genomic methylation in both imprinted and non-imprinted genes as a key mechanism in the development of cancer.

The effect of aging on nasal mucociliary clearance, beat frequency, and ultrastructure of respiratory cilia

The increased susceptibility of the elderly to lower respiratory tract infection cannot be fully explained. Although mucociliary clearance, which is affected by ciliary beating and ultrastructure, plays a crucial role in the defense of the airways against inhaled microbes, little is known of the effects of aging on these parameters. We studied the nasal mucociliary clearance (NMCC) time, ciliary beat frequency, and ultrastructure of respiratory cilia in a cohort of healthy volunteers (age range 11 to 90 yr). Ciliary beat frequency of ciliated nasal epithelial cells was obtained via an established photometric method, and NMCC time was measured with the saccharine test. There was a correlation of ciliary beat frequency (r = -0.48, p = 0.0001) and NMCC time r = 0.64, p < 0.001) with increasing age. Transmission electron microscopy revealed an increase in the percent of subjects exhibiting microtubular disarrangement and single central microtubules with aging (p = 0.002 and p = 0.005, respectively). Subjects older than 40 yr of age had significantly slower ciliary beat frequency, higher percent of ciliary cross-sections displaying single tubules, and longer NMCC time than their younger counterparts (p < 0.05). These findings may help explain the frequent occurrence of respiratory infection in the elderly.

A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong

BACKGROUND

Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong.

METHODS

Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned. Subsequently, full polysomnographic (PSG) examinations were conducted in 153 questionnaire respondents. Subjects with an apnea-hypopnea index (AHI) > or =5 were recalled for clinical assessment.

RESULTS

Questionnaire respondents were similar in age and body mass index (BMI) to the general community in the target age range and gender. Habitual snoring was reported by 23% of this cohort and was associated with excessive daytime sleepiness (EDS), hypertension, witnessed abnormal breathing pattern, BMI, and leg movements during sleep. Allowing for subject bias in undergoing PSG, the estimated prevalence of SDB and obstructive sleep apnea syndrome (OSAS) (defined as SDB in the presence of EDS) at various AHI cutoff threshold values was 8.8% and 4.1% (AHI > or =5), 6.3% and 3.2% (AHI > or =10), and 5.3% and 3.1% (AHI > or =15). Multiple stepwise logistic regression analysis identified BMI, habitual snoring, time taken to fall asleep, and age as predictors of SDB at AHI > or =5. Analysis of anthropometric parameters indicated that the relative risk of OSAS attributable to obesity was less than in white subjects.

CONCLUSION

This community-based study of sleep apnea among middle-aged men in Hong Kong using full PSG demonstrated an estimated prevalence of OSAS (AHI > or =5 and EDS) at 4.1%. Increasing BMI and age were associated with SDB, although factors other than adiposity may also have an important pathogenic role in OSA in Chinese subjects.

Development of a Marine Sediment Pollution Index

To facilitate translation of the state of marine sediment quality for public information, a pollution index was developed from the results of a routine monitoring program. Principal component analysis (PCA) of 24 variables at 64 monitoring stations from 1987 to 1997 was carried out to identify the most important parameters that were applied in the index formulation. Of the 24 variables, six (Cr, Cu, Ni, chemical oxygen demand, Zn, Mn) were selected on the basis of their high PCA loadings. The derived Marine Sediment Pollution Index, rating from 0 to 100, reflected the general trend in the monitoring areas. The index was also found to have a significant negative correlation (P < 0.05) with the benthic species diversity and toxicity of the sediment, indicating its usefulness in reflecting marine sediment quality. The application of PCA to identify important variables from a monitoring program would reduce sampling resources, as parameters that did not show significant spatial or temporal variations could be analyzed in a lesser frequency than those that were identified to be more important from the results of PCA.

Circulating nitric oxide is suppressed in obstructive sleep apnea and is reversed by nasal continuous positive airway pressure

Epidemiological studies have implicated obstructive sleep apnea (OSA) as an independent comorbid factor in cardiovascular and cerebrovascular diseases. The recurrent episodes of occlusion of upper airways during sleep result in pathophysiological changes that may predispose to vascular diseases, and we postulate that nitric oxide may be one of the mediators involved. This study investigates the levels of circulating nitric oxide (NO), measured as serum nitrites and nitrates, in the early morning in OSA subjects compared with control subjects, and the effect of overnight nasal continuous positive airway pressure (nCPAP) in OSA subjects. Thirty men with moderate to severe OSA (age = 41.9 +/- 9.0; apnea-hypopnea index, AHI = 48.0 +/- 18.1) were compared with 40 healthy men (age = 40.6 +/- 5.4; AHI = 1.4 +/- 1.2). Serum nitrite/nitrate levels were significantly lower in OSA subjects (OSA = 38.9 +/- 22.9 microM, control subjects = 63.1 +/- 47.5 microM, p = 0.015). There was significant negative correlation between serum nitrites/nitrates and the following parameters: AHI (r = -0.389, p = 0.001), oxygen desaturation time (r = -0.346, p = 0.004), and systolic blood pressure (BP) (r = -0.335, p = 0.005). Stepwise multiple linear regression with systolic or diastolic BP as the dependent variable identified serum nitrites/nitrates as the only significant correlate. Twenty-two OSA subjects had measurements of serum NO at baseline and after an overnight application nCPAP. There was significant increase in serum NO after nCPAP (baseline = 30.5 +/- 14.4 microM, after nCPAP = 81.0 +/- 82.1 microM, p = 0.01). This study demonstrates, for the first time, that circulating NO is suppressed in OSA, and this is promptly reversible with the use of nCPAP. The findings offer support for nitric oxide being one of the mediators involved in the acute hemodynamic regulation and long-term vascular remodeling in OSA.

Serial HRCT lung changes after 3-field radiation treatment of breast cancer

AIMS

To document serial high resolution computed tomography (HRCT) features of lung injury after 3-field radiotherapy for breast cancer.

MATERIALS AND METHODS

Thirty women who received opposing tangential chest wall and supraclavicular field (SCF) irradiation after breast surgery were recruited. Thoracic HRCT was performed before and at 1, 3, 6 and 12 months after radiotherapy (RT). Lung injury at 3 months was quantified by applying a scoring system to each HRCT section. Findings were correlated with spirometric lung function tests.

RESULTS

There was HRCT evidence of lung injury in 27 (90%) women at 1 month and in all 30 patients at 3 months. Spirometric lung function declined post-RT (P < 0.05), correlating with an increased SCF acute lung injury score at 3 months [r = -0.54 and -0.46, P = 0.01 and 0.03 for forced expiratory volume in 1st (FEV(1)) and forced vital capacity (FVC), respectively]. Lung injury on HRCT progressed from ground glass opacification at 1 month to nodular consolidation (3 months), increasing linear densities (6 months), and finally to residual subpleural linear and dense opacities (12 months).

CONCLUSION

There is a high incidence of lung injury associated with 3-field radiotherapy for breast cancer, with concurrent SCF irradiation increasing the risk of lung damage and functional impairment. A characteristic sequence of HRCT changes is seen in most patients receiving this type of radiotherapy.Ooi, G. C. (2000). Clinical Radiology55, 817-824.

Up-regulation of circulating adhesion molecules in bronchiectasis

Adhesion molecules are expressed on the surface of endothelial cells and leukocytes and are responsible for mediating the migration of intravascular leukocytes into inflamed tissue. Intensive recruitment of neutrophils into the airways occurs in bronchiectasis, although little is known about the role of adhesion molecules in this process. The authors, therefore, determined serum levels of E-selectin, intercellular adhesion molecule (ICAM)-1 and vascular adhesion molecule (VCAM)-1 in stable bronchiectasis patients (n=37) and healthy control subjects (n=17), and evaluated their relationship with clinical markers of disease severity in bronchiectasis. Serum levels of E-selectin, ICAM-1 and VCAM-1 in bronchiectasis patients were significantly higher than those in control subjects (p=0.02, <0.0001 and 0.0002 respectively). Both E-selectin and ICAM-1 levels were inversely related to forced expiratory volume in one second (FEV1)% predicted (r=-0.57, p<0.001; and r=-0.53, p=0.001 respectively), and FVC% predicted (r=-0.52, p=0.002; and r=-0.46, p=0.005). This was not the case for VCAM-1 levels. There was a correlation between serum ICAM-1 levels and 24 h sputum volume (r=0.34, p= 0.04). Serum E-selectin and ICAM-1, but not VCAM-1, levels showed correlation with the number of lung lobes affected by bronchiectasis (r=0.35, p=0.04 and r=0.34, p=0.04 respectively). These original observations strongly suggest that E-selectin, intercellular adhesion molecule-1 and Vascular adhesion molecule-1 could play a significant role in the pathogenesis of bronchiectasis.

Chemoradiotherapy for advanced lymphoepithelioma-like carcinoma of the lung

Lymphoepithelioma-like carcinoma (LELC) of the lung, an Epstein-Barr virus-associated undifferentiated carcinoma, is a rare entity of pulmonary malignancy. It tends to affect young non-smoking Asians and is often resectable. However, little is known of the treatment of the even rarer locally advanced or metastatic cases. We report our experience of three Chinese patients with advanced LELC of the lung who were treated with combination-chemotherapy (5-fluorouracil, leucovorin, and cisplatin) and radiotherapy. The encouraging response of these patients supports the use of this regime in other patients.

Diagnostic yield of bronchoscopic sampling methods in bronchial carcinoma

OBJECTIVES

The aim was to study the yield of malignant or suspicious cells from bronchoalveolar lavage (BAL), endobronchial biopsy (BX) and endobronchial brushing (BR) specimens obtained at bronchoscopy.

METHODOLOGY

We prospectively followed up all patients who had undergone bronchoscopy and studied those with subsequent diagnosis of bronchial carcinoma at a tertiary referral centre. Bronchoalveolar lavage, BX and BR were performed, sequentially whenever possible, by one pulmonologist. The parameters assessed were age, gender, macroscopic bronchoscopic findings, TNM staging, radiological findings, histological typing, and diagnostic yield from BAL, BX, and BR.

RESULTS

One hundred patients (31 females, 69 males; mean age +/- SD, 61.8+/-12.7 years; range 32-81 years) were studied between 1995 and 1997. Of these, BAL, BX and BR were performed on 100, 64 and 37 cases which yielded diagnostic specimens for bronchial carcinoma in 69, 78.1, and 62.2% of cases, respectively (P > 0.05). Diagnostic specimens were therefore obtained in 69,50, and 23% of the entire patient cohort from BAL, BX, and BR, respectively (P < 0.001). The diagnostic yield of BAL was independent of patient age, gender, site of lesion, TNM staging, histological typing and macroscopic bronchoscopic findings. Addition of BX, BR and postbronchoscopic sputum sampling to BAL only increased the yield of diagnostic specimens for bronchial carcinoma by 7, 0, and 4%, respectively.

CONCLUSION

Bronchoalveolar lavage is a highly effective sampling method to obtain cytological evidence for bronchial carcinoma. The diagnostic yield for BAL is independent of tumour or other clinical characteristics. Further studies should be performed to confirm these important and clinically relevant findings.

Endobronchial actinomycosis associated with a foreign body

Primary endobronchial actinomycosis is an exceedingly rare condition which closely mimics bronchial carcinoma both clinically and radiologically. We report the case of a middle-aged Chinese man who had right lower lobe endobronchial actinomycosis associated with inhalation of a presumed chicken bone. The patient made a complete clinical and radiological recovery after a 2 month combined course of amoxycillin and clavulanate, after removal of the foreign body, which was only detected after using contiguous computed tomography. Our experience in the management of this patient should help clinicians in the investigation and management of this rare but treatable condition.

Helicobacter pylori sero-prevalence in asthma

Asthma is a very common respiratory disease which is characterized by the presence of cytokine-mediated airway inflammation leading to smooth muscle contraction, oedema and progressive airway damage in some cases. In light of our recent finding of an increased sero-prevalence of Helicobacter pylori in bronchiectasis, we have determined serum levels of H. pylori-specific IgG in asthmatic and control subjects. Altogether 90 consecutive asthmatic [mean age +/- SD 42.6+/-16 years and 52 female (F)] and 97 healthy control subjects (mean age +/- SD 43.2+/-13.3 years and 51 female (F); P = 0.78 and 0.39 respectively) were recruited prospectively. H. pylori sero-prevalence was not significantly different between asthmatic and control subjects (P>0.05). Serum H. pylori IgG levels did not correlate with FEV1 % predicted, FVC % predicted or duration of asthma (P>0.05). Similar to the results of previously published sero-epidemiological studies, there was a weak correlation between serum H. pylori IgG with increasing age (r = 0.43, P = 0.004). Despite the sero-epidemiological association of H. pylori infection with many inflammatory conditions, our data showed no such association for middle age asthmatic patients with mild intermittent asthma in our locality.

Endothelin-1 in stable bronchiectasis

Endothelin (ET)-1 has been suggested to promote neutrophil adhesion to endothelium, migration to inflamed areas, and release of elastase. ET-1 might therefore play a role in the pathogenesis of bronchiectasis, a chronic inflammatory and infective airway disease which is still poorly understood. Thirty five patients with stable bronchiectasis (20 females, mean age+/-SD 49.1+/-15.0 yrs) and 18 control subjects (8 females, 49.4+/-11.3 yrs) were recruited prospectively. The ET-1 levels in serum and sputum were measured by commercially available enzyme linked immunosorbent assay (ELISA) kits. Patients with Pseudomonas aeruginosa in their sputum had a significantly higher serum level of ET-1 (median 25.8, interquartile range 13-43.9 pg x mL(-1)) than patients without P. aeruginosa (0, 0-10.5 pg x mL(-1); p=0.0004) and healthy control subjects (4.6, 0-16.3 pg x mL(-1); p=0.002). However, patients with and without P. aeruginosa infection had no significant difference in sputum ET-1 level (p=0.15). There was no correlation between serum or sputum ET-1 levels with the serum and sputum levels of the interleukin (IL)-1beta, IL-8 and tumour necrosis factor (TNF)-alpha; the number of bronchiectasis lung lobes; and spirometry. Serum ET-1 level correlated with 24 h sputum volume for the bronchiectasis patients (r=0.51, p=0.002). The results, therefore, suggest a significant pathogenic role for endothelin-1 among Pseudomonas aeruginosa-infected patients with bronchiectasis. Further studies should be performed to evaluate the clinico-pathological correlation and expression of endothelin-1 in bronchiectasis.

Increased risk of vitamin B12 deficiency in patients with phenylketonuria on an unrestricted or relaxed diet

OBJECTIVE

To investigate whether dietary relaxation or cessation in patients with phenylketonuria (PKU) predisposes to vitamin B12 deficiency.

STUDY DESIGN

Patients with PKU aged 11 to 38 years underwent a neurologic examination and dietetic assessment and were divided according to their diet into 1 of 3 groups: Strict - those on a strict low phenylalanine (phe) diet with amino acid, mineral, and vitamin supplements; Relaxed - those on a total protein intake of approximately 1 g/kg/d with 50% of this from natural protein and 50% from amino acid, mineral, and vitamin supplements; Unrestricted - those on no formal protein restriction and not taking amino acid supplements. Assays of blood samples were taken for vitamin B12 and folate levels by standard assays. Results were analyzed with Student t test.

RESULTS

Vitamin B12 levels were significantly lower in the PKU groups on relaxed or unrestricted diets compared with the normal population (P <.0001 [unrestricted] and.0034 [relaxed]). Folate levels were significantly elevated in all PKU groups (<.0001).

CONCLUSION

Patients with PKU who are no longer under strict dietary control may be at risk from vitamin B12 deficiency. We recommend that all patients should remain under medical and dietetic supervision and in particular have their vitamin B12 status monitored.

Severe bronchiectasis in patients with "cystlike" structures within the ciliary shafts

Cilia are minute hairlike structures which sweep the respiratory tract clean by continuous beating. Ciliary dysfunction can occur which leads to development of bronchiectasis. We describe the clinical and investigation profiles of four patients who had early-onset severe and otherwise idiopathic bronchiectasis associated with a previously undescribed ciliary defect in which numerous cystlike structures are present within the ciliary shafts. The patients had otherwise normal ciliary microtubular ultrastructure and central microtubular orientation. Our newly described ciliary abnormality appears to be a primary defect and more systematic studies should be performed to evaluate this further.

Helicobacter pylori and upper gastrointestinal symptoms in bronchiectasis

The recently reported increase in seroprevalence of Helicobacter pylori, the causative pathogen in peptic ulceration, in bronchiectasis is unexplained. Therefore, the association of antibodies directed against cytotoxin-associated gene A(CagA), whose expression indicates virulence of H. pylori, and upper gastrointestinal symptoms in patients with stable bronchiectasis and healthy volunteers evaluated. One hundred patients (mean +/- SD age 55.1+/-16.7 yrs) and 94 healthy asymptomatic subjects (54.6+/-7.6 yrs) underwent clinical and physiological assessment and serum levels of anti-H. pylori CagA were determined using standard clinical and enzyme-linked immunosorbent assay techniques. Samples were positive for anti-H. pylori CagA in 11.7% of controls and 24% of bronchiectatic subjects (p = 0.03). There was, however, no association between serum H. pylori CagA immunoglobulin G level and forced expiratory volume in one second (FEV1), forced vital capacity (FVC), sputum volume, respiratory symptoms or upper respiratory gastrointestinal symptoms (p>0.05). Patients who suffered from acid regurgitation or upper abdominal distension had significantly lower FEV1 and FVC (as a percentage of the predicted value) compared to their counterparts. The results of anticytotoxin-associated gene A measurements in this study contrasted with the previous finding that anti-Helicobacter pylori immunoglobulin G correlated with sputum volume. These findings, therefore, suggest that Helicobacter pylori, should it have a pathogenic role in bronchiectasis, could act via noncytotoxin-associated gene A-mediated mechanisms, and, in this context, gastro-oesophageal reflux might be of importance in bronchiectasis.

A rabbit model of proliferative vitreoretinopathy induced by injection of astrocytic cultures

1. The objective of this study was to decipher whether proliferation of astrocytes and invasion of astrocytic processes into the retina could contribute to retinal detachment in a rabbit model. 2. Cultures of astrocytes were injected intravitreally into the eyes of albino rabbits. 3. Two weeks after injection, proliferation of astrocytes on the retinal surfaces was observed. Vascular endothelial growth factor (VEGF) and proliferative cell nuclear antigen (PCNA) were found by immunohistochemistry to be expressed in the center of the astrocytic growth. 4. Using the same immunohistochemical technique to visualize glial fibrillary acidic protein (GFAP), a marker for astrocytes, processes of astrocytes in the growth were observed to penetrate into the host retina. 5. Retinal detachment was then confirmed by ultrasound, histologically, and grossly 2 weeks after injection of astrocytes. 6. Histochemistry on esterase indicated chloroesterase positive cells inside the growth. The secretion of this form of esterase might soften the vitreous and enhanced retinal detachment. 7. Six weeks after injection, VEGF and PCNA decreased in the astrocytic growth but astrocytic processes still attached onto and penetrated the host retina. 8. This study suggests that astrocytes could be a major factor in inducing retinal detachment.

A comparative study on the efficacy of levofloxacin and ceftazidime in acute exacerbation of bronchiectasis

A prospective randomized study was performed in order to compare the efficacy of oral levofloxacin, a new S- isomer of ofloxacin, with intravenous ceftazidime in the empirical treatment of acute exacerbations of bronchiectasis. Consecutive patients with acute exacerbation of bronchiectasis were recruited at a tertiary referral centre and were randomized to receive 10 days' treatment with either oral levofloxacin (300 mg b..d.) or ceftazidime (1 g i.v.t.d.). Body temperature, cough score, dyspnoea score, sputum purulence and volume and white blood cell and neutrophil count were assessed on day 1 and day 10. Thirty-five patients (mean age 61 yrs, 15 males) completed the study; 17 of these were in the levofloxacin group. There was no significant difference in the distribution of sputum pathogens or clinical parameters between the two groups at entry to and completion of the study. Both groups of patients showed significant improvement in 24-h sputum volume, sputum purulence score, cough score and dyspnoea score (p<0.001) but there was no significant difference between these two groups at entry to or on completion of the study (p>0.05). The results of this study suggest that oral administration of levofloxacin is as effective as parenteral ceftazidime in the empirical treatment of exacerbations in bronchiectasis.