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H Barr

Publications and source records attributed to H Barr.

72 records · Page 4Linked to original sources
PubMed1987

Photodynamic therapy with phthalocyanine sensitisation: quantitative studies in a transplantable rat fibrosarcoma.

Photodynamic therapy (PDT) is a promising approach to the local destruction of malignant tumours, but little work has been done to determine which factors control the extent of tissue necrosis produced. Using a new photosensitiser, a sulphonated aluminium phthalocyanine (AlSPc) and light from an argon ion pumped dye laser at 675 nm, we quantified the effects of interstitial PDT in a transplantable fibrosarcoma in rats. At 100mW laser power, thermal effects were comparable to those of PDT, so subsequent studies were carried out at 50 mW, where thermal effects were minimal. The depth of PDT necrosis increased with the logarithm of the applied energy. Tissue concentration of AlSPc was measured by alkali extraction and at all times after sensitisation, correlated well with the necrosis produced with a given light dose. Peak tumour concentration of AlSPc occurred 24-48 h after sensitisation compared with a peak at 3 h in muscle. The peak ratio tumour:muscle was 2:1 at 24 h. Apart from a different time interval to reach the peak sensitiser concentration, the extent of tumour damage varied with the light and sensitiser parameters in a similar way to that found in normal liver, although the optical penetration depth was greater in the tumour (2.5 mm vs. 1.8 mm). At doses of AlSPc below 1 mg kg-1 the diameter of necrosis increased with the logarithm of the dose of sensitiser, and doubling the dose from 0.25 to 0.5 mg kg-1 increased the depth of necrosis by 50%. However, at higher doses, the changes were smaller and increasing the dose from 2.5 to 5 mg kg-1 only increased the necrosis by 10% for the same light dose. In all dose ranges, a given percentage increase in the tissue concentration of AlSPc gave a much smaller percentage increase in the extent of necrosis for the same light dose, suggesting that selectivity of necrosis between tumour and normal tissue is likely to be much less than the selectivity of retention of the photosensitiser. From these results, the extent of PDT necrosis in this fibrosarcoma is as predictable as it is in normal liver if the light dose, tissue concentration of AlSPc and optical penetration depth of the tissue are known. Further studies are now required on different tumour models to establish how tumours respond compared with adjacent normal tissue when the tumour is growing in its organ of origin rather than the non-physiological situation using a transplantable tumour as in this study.

Aluminum↗
PubMed1987

Palliative laser therapy for malignant dysphagia.

Seventy six patients with dysphagia caused by malignant tumours of the oesophagus or gastric cardia have been treated using the Neodymium Yttrium Aluminium Garnet (NdYag) laser. The laser was set to deliver 80-100 watts of power for 0.5-1 second pulses. To obtain improvement, patients on average needed four treatment sessions with a mean energy per treatment of 3586 joules. Follow up endoscopy and laser treatment was at four week intervals, unless the clinical or endoscopic results indicated otherwise. The immediate result was to allow 32% of patients to swallow anything they liked, a further 54% were able to take most solids and 9% were improved, or maintained on liquids only. The mortality of laser recanalisation and associated treatment was 5%. The improvement in swallowing was maintained until death in all but 15% of these patients, some of the 15% needed intubation to allow adequate swallowing. Endoscopic, or surgical intubation was required immediately in five patients after an initial laser course failed to provide improvement. The mean survival of the whole group was 19 weeks (range one to 112 weeks).

Adult↗
PubMed1987

Endoscopic laser palliation for advanced malignant dysphagia.

Palliative treatment of malignant dysphagia aims to optimise swallowing for the maximum time possible with the minimum of general distress to these seriously ill patients. Thirty four patients considered unsuitable for surgery because of advanced malignancy, other major pathology or in whom previous surgery had been unsuccessful were treated endoscopically with the Nd YAG laser. Significant improvement was achieved in 29 (85%). On a scale of 0-4 (0 = normal swallowing; 4 = dysphagia for all fluids), mean improvement was 1.7, with 25 patients (74%) able to swallow most, or all solids after treatment. With increasing experience, the average number of treatment sessions required for each patient became less; initial time in hospital became comparable to that needed for intubation. Failures were caused by inappropriate patient selection (3), or laser related perforation (2). The mean survival in the whole group was 19 weeks (range 2-44). Eighteen patients needed further treatment for recurrent dysphagia, a mean of six weeks (range 2-15) after initial therapy. Ten of these responded, but eight eventually required insertion of a prosthetic tube. The duration of good palliation was very variable after initial laser therapy.

Aged↗
PubMed1987

Oesophagogastric tumour in old age: palliative treatment by endoscopic laser photocoagulation.

The results of palliative treatment, with laser photocoagulation used alone, of oesophagogastric tumours in 23 patients mean age 81.9 (range 75-93) years are reviewed. Most were frail including five with metastatic disease, seven with cardiovascular disease and five with cerebrovascular disease. Dysphagia was the presenting symptom in 21 patients, two presented with an acute haematemesis. Improvement in swallowing was achieved in 19 (90.5%). Hospital stay was minimal, and 93.3% deaths were in the community. The only complication was perforated oesophagus in 1 patient, treated successfully by conservative management. We suggest laser photocoagulation as the palliative treatment of choice for dysphagia due to oesophagogastric tumour in the frail elderly patient even when the malignancy is at an advanced stage. The major benefit of the technique is the ability to maintain patients comfortably in the community rather than committing them to terminal care in a hospital environment.

Aged↗
PubMed1986

Endoscopic treatment of inoperable colorectal cancers with the Nd YAG laser.

Seventeen patients with cancers of the rectum or distal sigmoid and considered inoperable because of old age, severe concomitant disease or advanced stage of malignancy, were treated endoscopically with the Nd YAG laser. Symptoms included rectal bleeding, obstruction, diarrhoea and incontinence. Significant improvement was achieved in 15 (88 per cent) and there were no complications. The procedure was carried out with simple bowel preparation and minimal sedation and, for otherwise fit individuals, the mean total hospital stay was 6.8 days, with day case therapy sometimes possible. Three patients required further therapy for recurrent symptoms 6-8 weeks after treatment. Fourteen patients died 1-39 weeks after therapy (mean survival 15 weeks). Three are alive and free of bowel symptoms after 39-54 weeks. This technique is the only non-surgical therapy that can be used safely for lesions above the peritoneal reflection and provides palliation at least as good as electrocoagulation, cryotherapy and radiotherapy with minimal upset to these seriously ill patients.

Adenocarcinoma↗
PubMed1978

Follow-up study of patients treated by X-ray epilation for tinea capitis: psychiatric and psychometric evaluation.

To investigate the late effects of radiation to the head upon subclinical mental disorders, a psychiatric and psychometric evaluation was performed on 177 cases treated 10-29 years earlier for ringworm of the scalp by X-ray therapy (N :109) or, by chemotherapy (N :68). Analyses which controlled for educational level and family psychiatric disorders showed that, among whites, the irradiated group manifested more psychiatric symptoms and more deviant MMPI (Minnesota Multiphasic Personality Inventory) scores. They were also judged more maladjusted from their MMPI profiles, and more frequently had a history of treated psychiatric disorders; however, the psychiatrist's overall rating of current psychiatric status showed only a borderline differnece between the two groups. There were no significant differences between irradiated and chemotherapy treated blacks.

Adult↗
PubMedDate not supplied

Photodynamic therapy using 5-aminolaevulinic acid for oesophageal adenocarcinoma associated with Barrett's metaplasia.

Photodynamic therapy (PDT) is a novel technique for local endoscopic treatment of gastrointestinal neoplasia. Current photosensitisers for PDT may cause prolonged skin phototoxicity. 5-Aminolaevulinic acid (ALA), a precursor of the photosensitiser protoporphyrin IX (PpIX), is more acceptable because of its short half-life and preferential accumulation in mucosa and mucosal tumour. We have treated 12 patients, median age 73 years (range 55-88) with oesophageal adenocarcinoma arising from Barrett's metaplasia (two carcinomas-in-situ, grade 0; 10 carcinomas, grade 1-11A based on endoluminal ultrasound in two and CT scanning in 10 patients). ALA (60 and 75 mg/kg body weight) was given orally in two or five equally divided doses. The PpIX distribution in stomach, normal oesophagus, Barrett's mucosa and carcinoma was measured by quantitative fluorescence photometry. PDT was performed using laser light (630 nm) delivered via a cylindrical diffuser 4-6 h after the first dose of ALA. The patients received one to four sessions of PDT. PpIX accumulation in the mucosa was two to three times that in the lamina propria. The differential distribution between carcinomatous and normal oesophageal mucosa was less marked (carcinoma:normal mucosa ratio = 1.4). Higher doses of ALA increased PpIX accumulation in all tissues but did not increase the differential PpIX distribution between tumour and normal oesophageal mucosa. After PDT using ALA (ALA/PDT), all mucosa showed superficial white necrotic changes and the histology confirmed fibrinoid necrosis. One patient with carcinoma-in-situ had the tumour eradicated after one treatment with no recurrence at 28 months. Another patient with a small T1 tumour required four ALA/PDT treatments, and died of other disease after 36 months. There was no evidence of recurrence. The tumour bulk in the other carcinomas was not significantly reduced. ALA/PDT has a potential for the eradication of small tumours but careful patient selection with endoluminal ultrasound is needed when using ALA/PDT to treat oesophageal cancer.

Adenocarcinoma↗
PubMedDate not supplied

Occult femoral artery injury in relation to fracture of the femoral shaft.

Recognized injury of the femoral artery occurs in two per cent of patients with fracture of the femoral shaft. Delay in detection of these arterial injuries has led to unsatisfactory results in a young group of patients. Therefore, 40 patients who had suffered fracture of the femoral shaft 6-20 months (mean 13 months) prior to examination, were haemodynamically assessed using Doppler ankle/arm pressure indices to determine the incidence of occult femoral artery injury. Six patients (15%) exhibited haemodynamically significant abnormalities all in relation to previously injured limbs.

Adolescent↗