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PubMed1991

Effect of beta radiation on proliferating human Tenon's capsule fibroblasts.

The effects of different doses of beta radiation from a strontium-90 source on the proliferation of human Tenon's capsule fibroblasts were studied. The cultured fibroblasts were exposed to doses of 100, 250, 500, 750, 1000, 1500, and 3000 rads, and cell numbers were counted at days 3, 7, and 14. Treatment inhibited the proliferation of the fibroblasts. At seven days the cells exposed to 3000 rads showed a decrease relative to the starting cell numbers, and at 14 days the cells exposed to 1500 and 3000 rads showed a decrease in cell numbers. The doses of radiation which inhibited cell proliferation more than 50% (at day 7 and 14) and yet did not cause a decrease in the cell population were 500, 750, and 1000 rads. beta Radiation reduces the proliferation of human Tenon's capsule fibroblasts, and at higher doses this effect may be more pronounced one and two weeks after irradiation.

Beta Particles↗
PubMed1991

Trabeculectomy combined with beta irradiation for congenital glaucoma.

Sixty-six eyes with congenital glaucoma were subjected to trabeculectomy between July 1975 and June 1989 are presented. Thirty-one were treated with beta irradiation at the time of surgery with a strontium-90 applicator; 35 were not treated with beta irradiation. The usual dose was 750 rad. Analysis was limited to three years because of the shorter follow-up of the irradiated eyes. Failure in the two groups was compared statistically. When failure was categorised as IOP greater than 21 mm Hg, beta irradiation was found to be significantly protective with an adjusted risk ratio of 0.31 (95% confidence interval 0.11-0.90, p less than 0.05). Failure categorised as the need for additional medical treatment or further surgery showed significant protection with an adjusted risk ratio of 0.33 (confidence interval 0.12-0.94, p less than 0.05). Multiple regression models were used for the analysis of intraocular pressure; beta irradiation was associated with a significantly lower IOP at six months, one year, and three years (p less than 0.05). Other factors identified as being associated with a reduced failure rate or lower IOP were: no previous topical glaucoma medications: age over seven years; lack of previous surgery involving the conjunctiva. The results indicate that beta irradiation may have a beneficial effect on the prognosis of trabeculectomy in children with congenital glaucoma. However, because of the retrospective and observational nature of the study, the results must be regarded as tentative.

Adolescent↗
PubMed1998

Split thickness buccal mucous membrane grafts and beta irradiation in the treatment of recurrent pterygium.

BACKGROUND: Pterygium is a common problem and after surgical removal may recur in up to 80% of cases, depending on the technique of primary excision. Recurrent pterygia can be aggressive and repeated excision may result in severe conjunctival scarring and shortening, resulting in insufficient conjunctiva to perform further grafting and lid surgery. When there is insufficient autologous conjunctiva, mucous membrane must be obtained from other sites. Full thickness buccal mucous membrane grafts have been described, but they may result in a beefy red appearance, with graft contraction and a poor tear film. METHOD: The use of split thickness buccal mucous membrane grafts is described in three patients with recurrent pterygium, two in combination with lamellar keratoplasty. beta Irradiation was used as adjuvant therapy in all cases. RESULTS: In all three cases an acceptable cosmetic appearance was achieved, with no recurrence of the pterygium, and a good range of eye movements. CONCLUSIONS: It is recommended that split thickness buccal mucosal grafts, combined with beta irradiation, should be considered in complex cases of pterygium recurrence when there is insufficient autologous conjunctiva and conjunctival shortening with restricted eye movements.

Adult↗
PubMed1998

Long term growth arrest of human Tenon's fibroblasts following single applications of beta radiation.

AIMS/BACKGROUND: Antimetabolites are increasingly used to manipulate the healing response after filtration surgery, but problems with thin cystic blebs have been encountered with the liquid agents commonly used such as 5-fluorouracil and mitomycin C. beta Radiation appears to be a useful adjuvant treatment for preventing scarring after trabeculectomy, resulting in diffuse rather than cystic bleb formation, but much of the basic cell biology of the ocular fibroblast response to beta radiation remains unclear. The effects of beta radiation on ocular fibroblast proliferation and cell cycling were investigated to determine the nature and duration of these effects on these cells. METHODS: In vitro cell culture techniques were used to investigate fibroblast proliferation. Cell viability was studied using trypan blue dye exclusion. The effect of radiation on cell cycling was investigated using bromodeoxyuridine uptake. p53 expression was demonstrated using immunocytochemistry. RESULTS: beta Radiation inhibited fibroblast proliferation in a dose dependent manner. Early cell death was not a prominent feature, but irradiated fibroblasts demonstrated a rapid onset and sustained period of growth arrest. p53 expression was found to be increased in irradiated cells. CONCLUSIONS: Single doses of beta radiation significantly inhibit Tenon's capsule fibroblast proliferation in vitro over a 28 day period. This inhibition is the result of a rapid onset and sustained period of growth arrest in irradiated cells. Irradiated fibroblasts show an increase in p53 expression, a nuclear phosphoprotein which has been associated with control of the cell cycle. Single applications of beta radiation may be an effective treatment for the prevention of bleb failure as a result of prolonged growth arrest of Tenon's capsule fibroblasts.

Beta Particles↗
PubMed2000

Comparative study of intraoperative mitomycin C and beta irradiation in pterygium surgery.

AIMS: To compare the rate of recurrence and complication after surgery for primary pterygium performed by one surgeon using either intraoperative mitomycin C or beta irradiation. METHODS: A retrospective study was performed of 164 eyes in 164 patients who had undergone primary pterygium surgery. After the pterygium was excised, the bare sclera was covered by sliding adjacent superior conjunctiva. 103 eyes received intraoperative mitomycin C (0.04%, 150 seconds) and 61 eyes beta irradiation (total dose 21.6 Gy). The mean follow up period was 20.2 (SD 17.9) months (range 1-66 months). Recurrence was defined as the postoperative regrowth of fibrovascular tissue crossing the corneoscleral limbus. RESULTS: The recurrence rate after mitomycin C and beta irradiation was 8.74% and 23.0% of eyes, respectively, after mean follow up of 17.9 and 31.2 months, respectively. The Kaplan-Meier survival analysis revealed a significantly better outcome for those who had intraoperative mitomycin C (Mantel-Cox log rank analysis, p=0.031). The mean interval to recurrence was not significantly different between the two groups. During the follow up, none of the patients showed side effects or reactions related to mitomycin C or beta irradiation. CONCLUSIONS: The intraoperative administration of 0.04% mitomycin C is more effective than beta irradiation as an adjunctive treatment for pterygium surgery in the patient population examined in this study.

Adult↗
PubMed2006

Effect of beta radiation on success of glaucoma drainage surgery in South Africa: randomised controlled trial.

OBJECTIVE: To evaluate whether beta radiation may offer a practical method of improving surgical success for glaucoma drainage surgery in South Africa. DESIGN: Double blind, randomised controlled trial. SETTING: Three public hospitals in South Africa. PARTICIPANTS: 450 black Africans with primary glaucoma. INTERVENTIONS: Trabeculectomy with 1000 cGy beta radiation or standard trabeculectomy without beta radiation (placebo). MAIN OUTCOME MEASURES: Primary outcome measure was surgical failure within 12 months (intraocular pressure > 21 mm Hg while receiving no treatment for ocular hypotension). Secondary outcomes were visual acuity, surgical reintervention for cataract, and intraoperative and postoperative complications. RESULTS: 320 people were recruited. beta radiation was given to 164; 20 (6%) were not seen again after surgery. One year after surgery the estimated risk of surgical failure was 30% (95% confidence interval 22% to 38%) in the placebo arm compared with 5% (2% to 10%) in the radiation arm. The radiation group experienced a higher incidence of operable cataract (18 participants) than the placebo group (five participants; P = 0.01). At two years the estimated risks with placebo and beta radiation were, respectively, 2.8% (0.9% to 8.3%) and 16.7% (10.0% to 27.3%). CONCLUSION: beta radiation substantially reduced the risk of surgical failure after glaucoma surgery. Some evidence was, however, found of an increased risk for cataract surgery (a known complication of trabeculectomy) in the beta radiation arm during the two years after surgery. TRIAL REGISTRATION: ISRCTN62430622 [controlled-trials.com].

Adult↗
PubMed2000

Outcome from balloon induced coronary artery dissection after intracoronary beta radiation.

OBJECTIVE: To evaluate the healing of balloon induced coronary artery dissection in individuals who have received beta radiation treatment and to propose a new intravascular ultrasound (IVUS) dissection score to facilitate the comparison of dissection through time. DESIGN: Retrospective study. SETTING: Tertiary referral centre. PATIENTS: 31 patients with stable angina pectoris, enrolled in the beta energy restenosis trial (BERT-1.5), were included. After excluding those who underwent stent implantation, the evaluable population was 22 patients. INTERVENTIONS: Balloon angioplasty and intracoronary radiation followed by quantitative coronary angiography (QCA) and IVUS. Repeat QCA and IVUS were performed at six month follow up. MAIN OUTCOME MEASURES: QCA and IVUS evidence of healing of dissection. Dissection classification for angiography was by the National Heart Lung Blood Institute scale. IVUS proven dissection was defined as partial or complete. The following IVUS defined characteristics of dissection were described in the affected coronary segments: length, depth, arc circumference, presence of flap, and dissection score. Dissection was defined as healed when all features of dissection had resolved. The calculated dose of radiation received by the dissected area in those with healed versus non-healed dissection was also compared. RESULTS: Angiography (type A = 5, B = 7, C = 4) and IVUS proven (partial = 12, complete = 4) dissections were seen in 16 patients following intervention. At six month follow up, six and eight unhealed dissections were seen by angiography (A = 2, B = 4) and IVUS (partial = 7, complete = 1), respectively. The mean IVUS dissection score was 5.2 (range 3-8) following the procedure, and 4.6 (range 3-7) at follow up. No correlation was found between the dose prescribed in the treated area and the presence of unhealed dissection. No change in anginal status was seen despite the presence of unhealed dissection. CONCLUSION: beta radiation appears to alter the normal healing process, resulting in unhealed dissection in certain individuals. In view of the delayed and abnormal healing observed, long term follow up is indicated given the possible late adverse effects of radiation. Although in this cohort no increase in cardiac events following coronary dissections was seen, larger populations are needed to confirm this phenomenon. Stenting of all coronary dissections may be warranted in patients scheduled for brachytherapy after balloon angioplasty.

Angina Pectoris↗
PubMed2004

Human coronary morphology after beta radiation brachytherapy of in-stent restenosis.

This case report discusses the human coronary morphological findings 18 hours after brachytherapy (beta radiation) of an in-stent restenosis. Brachytherapy produced aseptic inflammation of the periadventitial connective tissue integrating the vasa vasorum in the acute phase. The stent neointima eight months after stenting and acutely 18 hours after radiation consisted of the same cellular components as human stent neointima of specimen not additionally treated with radiation. No evidence of necrosis or excessive fibrotic alterations of the arterial vessel wall have been found.

Beta Particles↗
PubMed2005

Long term outcome after intracoronary beta radiation therapy.

OBJECTIVES: To determine the long term outcome after intracoronary beta radiation therapy (IRT). SETTING: Tertiary referral centre. METHODS: The rate of major adverse cardiac events (MACE) was retrospectively determined in 301 consecutive patients who were treated with IRT. MACE was defined as death, myocardial infarction, or any reintervention. Long term clinical outcome was obtained from an electronic database of hospital records and from questionnaires to the patients and referring physicians. Long term survival status was assessed by written inquiries to the municipal civil registries. RESULTS: The mean (SD) follow up was 3.6 (1.2) years. The cumulative incidence of MACE at six months was 19.1%, at one year 36.4%, and at four years 58.3%. The target lesion revascularisation (TLR) rate at six months was 12.9%, at one year 28.3%, and at four years 50.4%. From multivariate analysis, dose < 18 Gy was the most significant predictor of TLR. At four years the cumulative incidence of death was 3.8%, of myocardial infarction 13.4%, and of coronary artery bypass surgery 11.3%. Total vessel occlusion was documented in 12.3% of the patients. CONCLUSIONS: In the long term follow up of patients after IRT, there are increased adverse cardiac events beyond the first six months.

Beta Particles↗
PubMed2005

Superiority of sirolimus eluting stent compared with intracoronary beta radiation for treatment of in-stent restenosis: a matched comparison.

OBJECTIVE: To compare acute and follow up clinical and angiographic results after treatment of in-stent restenosis (ISR) by sirolimus eluting stents (SES) with results obtained after intracoronary radiation therapy (IRT). DESIGN: Matched pair analysis. METHODS: 62 consecutive ISR lesions (< 30 mm lesion length, reference diameter < 3.5 mm) in 62 patients were treated with SES. From a database of 174 lesions (n = 141 patients) treated for ISR by intracoronary beta radiation, 62 lesions (62 patients) were pair matched with the SES group for diabetes mellitus, lesion length, vessel size, and pattern of ISR. Six month angiographic and 12 month clinical follow up results were obtained. RESULTS: Baseline clinical and angiographic characteristics were similar between the groups (not significant). SES implantation resulted in significantly lower postprocedural in-lesion diameter stenosis than did IRT (mean (SD) 14.2 (9.5)% v 21.1 (10.6)%, p = 0.001), significantly higher minimum lumen diameter at follow up (1.91 (0.58) v 1.55 (0.72) mm, p = 0.005), and a higher net gain (1.16 (0.55) v 0.77 (0.70) mm, p = 0.002). Angiographic binary in-lesion restenosis rate at six months was 11% in the SES group and 29% in the IRT group (p = 0.046). In 16 ISR lesions SES were used after failed IRT and in 46 lesions for first time ISR. In-lesion late loss was higher after use of SES for failed IRT than after use of SES for first time ISR (0.61 (0.67) mm v 0.24 (0.41) mm, p = 0.018). In a multivariate analysis prior failed IRT was the only independent predictor for recurrent restenosis after SES for ISR (p = 0.052, odds ratio 5.8). Six patients (10%) in the SES group and 17 patients (27%) in the IRT group underwent target lesion revascularisation during the 12 months of follow up (p = 0.022). CONCLUSIONS: In this non-randomised matched cohort SES achieved acute and follow up results superior to IRT for treatment of ISR even if cases of failed IRT are included. Failed IRT is a predictor of impaired SES effectiveness.

Beta Particles↗
PubMed2002

Effect of pre-exposure to beta rays of tritium on some biochemical parameters measured in organs of rats subsequently irradiated with fast neutrons.

The experiment examined biological responses produced by combined sequential exposure to low-level tritium contamination, followed by challenging irradiation with fast neutrons. Modifications of endogenous antioxidant potential of different organs in rats were discussed in relation to tissue radiosensitivity. Rats pre-contaminated to 7 cGy and 35 cGy have been additionally irradiated to 1 Gy with fast neutrons. Lipid peroxide level was determined in liver, kidney, small intestine, spleen, bone marrow, and plasma. Reduced glutathione (GSH) level and glucose-6-phosphate dehydrogenase (G6PDH) activity were determined in erythrocytes. An in vitro thymidine uptake assay was performed in isolated bone marrow cells. The lipid peroxide level decreased significantly only in liver and kidney from rats pre-exposed to 35 cGy. For small intestine and spleen, tissues of comparatively higher radiosensitivity, no induced radioprotection was observed, as reflected in the homeostasis of the lipid peroxides. The same behavior was observed in bone marrow, the most radiosensitive tissue studied. However, the bone marrow thymidine-incorporation assay revealed a possible adaptive-type reaction in rats pre-exposed to 35 cGy. We conclude that for radiosensitive tissues pre-exposure to chronic low doses of low linear energy transfer (LET) irradiation has no protective effect on their antioxidant status, whereas a protective effect is observed in radioresistent tissues.

Adaptation, Physiological↗
PubMed1978

An efficient patient data entry system for a busy computer.

The authors describe an independent minicomputer consisting of a CRT and a cassette unit which was designed to store patient data and interact with the main computer at a convenient time. This system permits the computer to handle data entry and treatment planning functions simultaneously. The layout of the overall system, the function of the program and a time analysis of the system are discussed.

Beta Particles↗