Akt phosphorylation on Thr308 but not on Ser473 correlates with Akt protein kinase activity in human non-small cell lung cancer.

BACKGROUND: The activity of the protein kinase Akt is frequently dysregulated in cancer and is an important factor in the growth and survival of tumour cells. Akt activation involves the phosphorylation of two residues: threonine 308 (Thr308) in the activation loop and serine 473 (Ser473) in the C-terminal hydrophobic motif. Phosphorylation of Ser473 has been extensively studied in tumour samples as a correlate for Akt activity, yet the phosphorylation of Thr308 or of downstream Akt substrates is rarely assessed. METHODS: The phosphorylation status of Thr308 and Ser473 was compared with that of three separate Akt substrates - PRAS40, TSC2 and TBC1D4 - in fresh frozen samples of early-stage human non-small cell lung cancer (NSCLC). RESULTS: Akt Thr308 phosphorylation correlated with the phosphorylation of each Akt substrate tested, whereas Akt Ser473 phosphorylation did not correlate with the phosphorylation of any of the substrates examined. CONCLUSION: The phosphorylation of Thr308 is a more reliable biomarker for the protein kinase activity of Akt in tumour samples than Ser473. Any evaluation of the link between Akt phosphorylation or activity in tumour samples and the prediction or prognosis of disease should, therefore, focus on measuring the phosphorylation of Akt on Thr308 and/or at least one downstream Akt substrate, rather than Akt Ser473 phosphorylation alone.

[Recommendations for training courses in bronchoscopy]. / Empfehlungen zu Trainingskursen in der Bronchoskopie.

Bronchoscopic training courses are an essential part of the education in bronchoscopy for all kinds of specialisations and professions performing such investigations. All aspects of the application should be mentioned during a course. These recommendations are necessary because the number of bronchoscopies performed in the last years has increased due to the increasing number of patients, improved equipment and better availability. Courses should provide the basic knowledge including main points of indications, preconditions for the procedure and decisions of consequence after bronchoscopy. Participants should be trained in the skills of correct handling and performing flexible bronchoscopies in training dummies. Necessary competence requirements on the course instructor are adequate professional qualifications, paedagogic skills and the availability of appropriate teaching material. Quality assurance of the course should be achieved by consequent evaluation. A widely spread field of bronchoscopic applications can improve patient care in many medical specialisations.

Interstitial laser photocoagulation and interstitial photodynamic therapy of normal lung parenchyma in the pig.

Interstitial laser photocoagulation (ILP) and interstitial photodynamic therapy (PDT) involve delivery of light to lesions in solid organs using thin fibres passed through needles inserted percutaneously under image guidance. In ILP, the laser energy heats the tissue, whereas in PDT it activates a previously administered photosensitising agent. This study looks at their potential for treating localised, small, peripheral lung cancers in patients unsuitable for surgery. Experiments were undertaken on nine normal pigs, up to four fibres being inserted into the lung parenchyma percutaneously under X-ray guidance (ILP: 2-3 W, 1000 q/fibre, from 805 nm diode laser, PDT, 100-200 J/fibre from 652 nm diode laser at 50-100 W, 3 days after 0.15 mg/kg mTHPC). Animals were killed from 3 days to 3 months later and the treated areas examined macroscopically and microscopically. Both techniques were well tolerated, producing well-defined, localised lesions, typically 3.5 x 2 x 2 cm using four fibres. Histology showed thermal coagulative necrosis after ILP and haemorrhagic necrosis after PDT. Early small haematomas and late cavitation were sometimes seen after ILP, but not after PDT. PDT lesions healed with preservation of larger arteries and bronchi in the treated area. A few small pneumothoraces were seen which resolved spontaneously, probably related to the chest wall puncture. It was concluded that ILP and PDT lesions of a size large enough to cover a small tumour can be made safely in the lung parenchyma, although healing was better after PDT. Pilot clinical studies with both techniques are now justified on carefully selected patients.

Fine-needle interstitial photodynamic therapy of the lung parenchyma: photosensitizer distribution and morphologic effects of treatment.

STUDY OBJECTIVE: To look at the effect of interstitial photodynamic therapy (PDT) in normal lung parenchyma to assess its potential for treating localized, peripheral lung tumors. DESIGN: Studies were performed on normal Wistar rats using the photosensitizer meso-tetrahydroxyphenyl chlorine. Drug distribution was measured by fluorescence microscopy on tissue sections. Light was delivered to the lungs via a single fiber inserted percutaneously under x-ray control and the PDT effect studied in animals killed at times up to 6 months later. RESULTS: Fluorescence studies showed that the drug was initially distributed throughout the lung, but was later predominantly in the vasculature, bronchi, and macrophages. PDT produced sharply defined zones of hemorrhagic necrosis up to 12 mm in diameter that healed with regeneration of bronchial epithelium and local fibrosis. Different histologic effects were seen between drug light intervals of 1 and 3 days. Treatment was well tolerated, there was a low incidence of pneumothorax, and as long as the fiber tip was within the lung parenchyma, there was no damage to adjacent tissues. CONCLUSION: Interstitial PDT produces zones of necrosis in normal lung that heal safely by a percutaneous technique without affecting adjacent areas of untreated lung. If the lesion size can be increased by using multiple fibers, this could be a promising new technique for treating localized, peripheral lung cancers in patients who are unfit for surgery.

Multi-centre clinical respiratory research: a new approach?

BACKGROUND: Recruitment to clinical trials organised by the research committee of the British Thoracic Society (BTS) has declined. We suspected that this was due to increasing workloads for consultant physicians in the National Health Service (NHS). We investigated possible causes in study 1 and a possible solution in study 2. METHODS: Study 1--a questionnaire was sent to BTS members listing possible factors that might deter them from entering patients into trials. These were scored on a 0-5 scale. Study 2--we set up 13 panels of experts to cover all major fields of respiratory medicine. They were asked to design projects that would address the most important research questions that could be answered by multi-centre clinical trials. We sent 11 projects for scoring to consultant members of the BTS who were asked to score them on scientific merit and on their ability to contribute patients to the study. RESULTS: Study 1--of the 59% of consultants who responded, 77% said that competition with increasing demands on their time was the major reason for not participating. Study 2--40% of consultants returned project scores. Three projects were subsequently selected for grant application. CONCLUSIONS: Clinical research in the UK is under threat from increasing workloads on consultants. One solution to this problem is a national approach to commission major projects. The most important clinical research questions might then still be answered in the limited time available to consultants.

Interstitial laser photocoagulation of normal lung parenchyma in rats.

BACKGROUND: Management of peripheral lung tumours may be risky in patients with poor lung function or in the elderly. A new possibility is interstitial laser photocoagulation (ILP) in which tumours are gently coagulated using thin laser fibres placed percutaneously under radiological guidance. This could have a useful palliative role in selected patients, but to be safe the effects on normal lung parenchyma must first be understood. This paper describes the creation and healing of ILP lesions in the normal rat lung. METHODS: ILP was performed using single laser fibres placed percutaneously in the left lung of normal rats under general anaesthetic with radiological guidance (laser power 1-3 W at 805 nm, treatment time 250-1000 s). The lesion size and healing were studied in rats killed at times from three days to six months after treatment, the bursting pressure was measured, and any complications noted. RESULTS: Zones of necrosis up to 12 mm in diameter were produced, the size depending on the laser power and treatment time. Histological examination showed typical thermal effects with complete healing with fibrosis by two months. The effect was very localised with remarkably little effect on the structure and function of the rest of the lung. Adverse effects in the lung parenchyma only occurred if the ILP lesion involved the hilar vessels or the oesophagus, causing pulmonary congestion and perforation, respectively. Pneumothorax was seen in 6% of cases. CONCLUSIONS: ILP with a single fibre can produce a localised zone of necrosis in normal lung parenchyma which heals safely and which has little effect on the rest of the lung. Further study of this technique using multiple fibres in a larger animal model is warranted to see if it is feasible and safe to produce a large enough volume of necrosis to be of value in the treatment of small peripheral lung tumours in patients who are unsuitable for surgery or palliative radiotherapy.

Primary tracheal tumours: a national survey.

BACKGROUND: Primary tracheal tumours are rare, so few physicians have extensive experience of their management. No direct comparisons have been made of surgical and radiotherapy treatment. METHODS: A postal survey of cases presenting in the last 10 years in the United Kingdom was conducted. Results were expressed as cumulative survival and survival curves were compared by the log rank test. RESULTS: Three hundred and twenty one patients were recruited. Overall five year survival rates were 25% for squamous cell carcinomas, and 80% for adenoid cystic carcinoma; 62% received radiotherapy but only 10% underwent surgery. Small cell carcinoma was more common than expected with an incidence of 6%. In patients with squamous carcinoma improved survival was seen in those with tumour in the upper trachea. High dose radiotherapy was more effective than low dose only in tumours of the upper trachea and in squamous carcinoma. In adenoid cystic carcinoma no significant difference in survival rate was seen between treatment with radiotherapy and surgery. No histological diagnosis was made in 44 patients, the most common reason being fear over the safety of fibreoptic bronchoscopy; however, this group had a cumulative survival at five years of 46%. CONCLUSIONS: Survival may be somewhat better in cases with tracheal tumours than in those with bronchial tumours. Small cell carcinoma is less rare than was previously thought. Upper tracheal tumours may merit more aggressive therapy. It is important to make a histological diagnosis even if rigid bronchoscopy is necessary, and referral to specialist centres is recommended. A larger prospective study is required to compare the value of surgery and radiotherapy.

Experimental studies to assess the potential of photodynamic therapy for the treatment of bronchial carcinomas.

BACKGROUND: Photodynamic therapy (PDT) is a technique for producing localised tissue necrosis with light after prior administration of a photosensitising drug. There is some selectivity of uptake of photosensitisers in malignant tissue, although this is difficult to exploit. Full thickness necrosis in normal and neoplastic colon heals without perforation because of a lack of effect on collagen, making local cure a possibility. The experiments described here aim to establish whether these conclusions are also valid for bronchial tumours. METHODS: In pharmacokinetic studies normal rats were given 5 mg/kg of the photosensitiser aluminium sulphonated phthalocyanine (A1SPc) intravenously and killed up to one month later. The distribution of A1SPc in the trachea was measured by chemical extraction and fluorescence microscopy. In subsequent experiments sensitised animals were treated with light delivered to the tracheal mucosa through a thin flexible fibre and the resultant lesions were studied for their size, mechanical strength, and healing. A series of resected human bronchial carcinomas were examined histologically for their collagen content. RESULTS: The tracheal concentration of A1SPc in normal rats was maximum 1-20 hours after administration. Fluorescence microscopy revealed that most was in the perichondrium and submucosal stroma, with little in the cartilage. Light exposure showed necrosis of the soft tissues which healed by regeneration, but no effect on cartilage and no reduction in the mechanical strength of the trachea at any stage. Histological examination of resected human bronchial carcinomas showed more collagen in the tumour areas than would be found in normal regions. CONCLUSIONS: PDT leads to necrosis of the soft tissues of the normal trachea but there is complete healing by regeneration, no risk of perforation (due to collagen preservation), and no effect on cartilage. Human bronchial carcinomas apparently contain more collagen than normal bronchi which may give protection against perforation following necrosis induced by PDT. PDT may have a role in eradicating small volumes of tumour tissue in situ and could be valuable for treating (1) small carcinomas in patients unfit for resection, (2) tumour remaining after surgical resection, (3) stump recurrences, or (4) to prolong palliation of tumours after debulking with the NdYAG laser.

Value of pulse oximetry in screening for long-term oxygen therapy requirement.

Pulse oximetry, combined with spirometry, was evaluated as a method of selecting chronic obstructive pulmonary disease (COPD) out-patients requiring definitive arterial blood gas analysis for long-term oxygen therapy (LTOT) assessment. A relatively high screening arterial oxygen saturation by pulse oximetry (SaO2) level was set, in order to maximize sensitivity. All 113 COPD out-patients attending the hospital clinic over a 6 month period were screened. Sixty had a forced expiratory volume in one second < 1.5 l and 26 had an SaO2 < or = 92%. These 26 underwent arterial blood gas analysis. Nine had an arterial oxygen tension < 7.3 kPa all with an arterial carbon dioxide tension (PaCO2) > 6 kPa. A further eight had a PaO2 < 8 kPa. This produced a sensitivity of 100% and specificity of 69% for oximetry in the detection of PaO2 < 7.3 kPa determined by direct arterial puncture and 100% and 86% respectively for detecting a PaO2 < 8 kPa. Although the poor specificity of oximetry in the crucial PaO2 range makes it unsuitable, when used alone, for prescription of LTOT, it may prove valuable in selecting patients who require further definitive arterial blood gas analysis.

Tracheal tumours: could treatment be better?

The rarity of primary tracheal tumours makes research into their natural history and treatment very difficult. Diagnosis is often made too late for cure. Palliation has improved with the introduction of laser resection, brachytherapy and stents. Squamous cell carcinoma may have a better prognosis in the trachea than in the lung. It has been assumed that surgery is the treatment of choice and up to 50% of the trachea can be resected with modern techniques. However, several of the largest surgical series have used mostly post-operative radiotherapy and really represent the results of combined therapy. High dose radiotherapy may achieve cure in some cases. Prospective studies of the relative merits of surgery and radiotherapy are urgently needed. The British Thoracic Society Research Committee is launching a national study at the present time.

The role of computed tomography (CT) in the investigation of unexplained haemoptysis.

Forty patients with a history of haemoptysis, normal chest radiographs apart from evidence of chronic airflow limitation, and normal fibreoptic bronchoscopy (or blood alone in the bronchial tree) were investigated by computed tomography (CT). Abnormalities were seen in 20 (50%) of the CT scans. Seven of the patients had evidence of bronchiectasis (18%), one of whom also had a mass. In four (10%) cases a mass alone was detected (two tuberculous, two malignant). In a further four (10%) scans alveolar consolidation was present and in three cases abnormal vessels were detected (7.5%). One patient had cystic changes shown in their scan and multiple nodules were shown in the final patient. The contralateral lungs of 93 patients undergoing CT for pre-operative assessment of bronchogenic carcinoma were used as controls. In six (6%) of these patients abnormalities were detected by CT. Pleural nodules were observed in two patients, fat in the transverse fissure in another, atelectasis in two patients and an apical bulla in the other abnormal scan. The relative risk for patients with unexplained haemoptysis having abnormal CT scans compared to the control group of patients was 7.75. We conclude that computed tomography is of value in the investigation of patients with unexplained haemoptysis.

Endoscopic palliation of tracheobronchial malignancies.

The prognosis for tracheobronchial tumours remains poor. Most patients can be offered only palliation. When the main symptom is breathlessness or refractory haemoptysis from a large airway tumour endoscopic treatment may be very effective. Over the last decade most attention has focused on the neodymium YAG laser. This often produces dramatic effects but has some important limitations. In the last few years better techniques for stenting and intrabronchial radiotherapy (brachytherapy) have also been developed. This article discusses the range of techniques now available and aims to help clinicians decide which patients may benefit from referral to centres providing these techniques.

Bronchography in the assessment of patients with lung collapse for endoscopic laser therapy.

In an attempt to improve selection of patients and the efficacy of endoscopic laser treatment, a bronchographic technique has been developed for patients with tumours causing complete endobronchial obstruction. This technique has shown patent distal airways in 16 out of 17 patients with a collapsed lung or lobe. These airways were abnormally dilated in each case, suggesting bronchiectasis. In one patient the appearances of bronchiectasis were sufficiently severe to decide against attempting treatment. Treatment was not attempted in another patient as a large cavity was seen within the collapsed lung and this was thought to carry a risk of postoperative infection and haemorrhage. Treatment with a neodymium YAG laser under general anaesthesia successfully recanalised the airway in 12 of the 15 remaining patients and was associated with a substantial reduction in breathlessness. The procedure was abandoned prematurely in one patient because of life threatening haemorrhage. In the remaining two patients in whom treatment was unsuccessful bronchography had suggested very extensive endobronchial obstruction. Spirometry and radionuclide lung scans were performed before and after treatment in eight patients treated successfully and showed significant improvements. Four patients were investigated within two weeks of lung re-expansion by repeat bronchography (three patients) or computed tomography (one patient); in each case the calibre of the airways had returned almost to normal. Thus the radiological demonstration of bronchial dilation in a collapsed lung does not necessarily imply a diagnosis of irreversible bronchiectasis and should not be regarded as a contraindication to treatment. It is concluded that preoperative bronchography provides reliable data on the extent of tumour, the patency of the distal airways, and presence of extensive cavitation. This information should facilitate successful laser treatment.

Elective resection of tumours of the trachea and main carina after endoscopic laser therapy.

In our patients with tumour affecting the trachea or carina elective surgery was carried out after endoscopic laser treatment. Laser treatment was performed as an emergency procedure in three of the patients, who presented with impending asphyxia; the improvement provided time in which to assess the disease, withdraw corticosteroids, and treat infection. The fourth patient was treated with the laser for life threatening haemoptysis, but further bleeding made it necessary to tamponade the tumour with a cuffed endotracheal tube for 24 hours. Elective resections of the trachea (three cases) and carina (one case) were performed successfully four to eight weeks after laser treatment. Frozen sections of the resection margins were clear in all cases and paraffin sections subsequently confirmed the localised nature of the lesions. All patients are alive and well with no evidence of tumour recurrence after 18 months to 4 years. Laser therapy appears to be an ideal preoperative treatment for patients with impending asphyxia but it may be of limited value in controlling very brisk haemorrhage.

Value of washings and brushings at fibreoptic bronchoscopy in the diagnosis of lung cancer.

A retrospective study was performed to evaluate the diagnostic yield for lung cancer from histological biopsy specimens and from washings and brushings for cytological examination taken at fibreoptic bronchoscopy. The records of 680 bronchoscopies were analysed. Of 300 patients eventually diagnosed as having a malignant lesion, 188 had had biopsy, washing, and brushing. Of these, 125 had endoscopically visible tumour (group A) and 63 had no abnormal findings or abnormal findings that were not diagnostic of malignancy (group B). In group A biopsy specimens gave a positive result in 76% of cases, washings in 49.6%, and brushings in 52%; biopsy material gave the only positive result in 22.4% of cases, washings in 2.2%, and brushings in 4.8%. In group B biopsy specimens were positive in 36.5%, washings in 38.1%, and brushings in 28.6%; biopsy gave the only positive result in 11.1% of cases, washing in 9.5%, and brushing in 3.2%. Washing had a higher diagnostic yield than brushing in group B. Biopsy and cytological examination of either washings or brushings were found to give over 95% of all positive results in group A, but in group B the combination of biopsy and washing was more often successful (94.3%) than biopsy and brushing (82.8%). It is concluded that for the maximum diagnostic yield in the diagnosis of lung cancer biopsy should be combined with cytology using both washings and brushings.

Changes in regional ventilation and perfusion of the lung after endoscopic laser treatment.

To determine whether endoscopic laser treatment improves both ventilation and perfusion in patients with advanced lung cancer, krypton-81m ventilation and technetium-99m labelled macro-aggregate perfusion scanning was performed immediately before and two or four days after treatment in a consecutive series of 28 patients. Twelve patients had not received any other treatment before laser therapy and 16 had undergone previous treatments that included radiotherapy. Ventilation and perfusion were quantified by expressing the number of counts in the affected lung as a percentage of the total counts. Ventilation and perfusion improved after laser treatment in 23 patients (82%). The mean ventilation score in the affected lung rose by 50% (p less than 0.001) and the mean perfusion score rose by 24% (p less than 0.001). Incremental changes in ventilation and perfusion scores were positively correlated (r = 0.80). Mean spirometric values, six minute walking distance, the Karnofsky performance index, and breathlessness and wellbeing scores also improved significantly. Patients with main bronchial obstruction who had had no radiotherapy showed the most striking improvements. It is concluded that the removal of intraluminal tumour from the bronchial tree leads to matched improvements in ventilation and perfusion in most patients and that this is associated with valuable improvement in symptoms.

Endoscopic applications of lasers in the bronchial tree.

Bronchial carcinoma causes some 30,000 deaths per year in the UK and only 10-20% of patients have any chance of surgical care. Radiotherapy and chemotherapy are mainly palliative treatments, yet they have considerable toxicity. In recent years laser bronchoscopy, with its advantages of speed, safety and freedom from toxicity, has proved a valuable addition to the established palliative therapy.