Malignant melanoma: analysis of dose fractionation in radiation therapy

Thirty-five patients with 67 measureable cutaneous or lymph node metastases from malignant melanoma were treated with radiation therapy in a variety of total doses and dose fractions. There was no correlation between total dose and response rate. However, there was a strong correlation between fraction size and response rate. There were four (9%) complete responses in 43 lesions treated with fractions less than or equal to 500 rad (5 Gy) compared with 12 (50%) complete responses in 24 lesions treated with fractions greater than 500 rad (5 Gy) (P = .0006). Initial response rate was found to correlate strongly with local control at 1 year. The results were then analyzed with respect to lesion size, cutaneous versus nodal lesions, and site of cutaneous lesion (trunk, head and neck, or extremity). Correlation between fraction size and response rate was independent of lesion size, although there were fewer complete responses with increasing lesion size. Correlation was not seen in nodal lesions but was particularly striking in cutaneous lesions. This correlation was statistically significant only for cutaneous lesions of the extremities.     

The effect of cataract extraction with implant in glaucomatous eyes

The effect of cataract surgery in patients with glaucoma controlled by either topical medication or surgery was assessed in 64 patients. At one year there was a small significant fall in intraocular pressure (IOP) for eyes without previous surgery (preoperative IOP 18.9 ±4.7, range 12 to 35 mmHg; postoperative IOP 16.3 ±3.4, range 10 to 26 mmHg; P<0.01) and also for those with previous surgery (preoperative IOP 15.0 ±4.3, range 3 to 22 mmHg; postoperative IOP 14.2 ±3.7, range 6 to 22 mmHg, P<0.05). There was a significantly greater incidence of high rise in IOP to 30 mmHg or more immediately after operation in patients without (32%) than those with previous surgery (13%) ( x 2 = 3.9; P<0.05). Complications were minimal in each group. lridotomy to deliver the nucleus was necessary in nine eyes without and 21 with previous surgery. Cataract extraction usually causes only a small fall in IOP in glaucomatous patients. If a separate corneal section is used there is no loss of function of the filtering bleb in patients with previous glaucoma surgery.     

Differential oxidative stress thresholds distinguishes cellular response to vascular occlusion and chemotoxicity in vivo

Background: A major effect of cyanide toxicity (CN) and vascular occlusion (VO) is the production of reactive oxygen species (ROS) linked with a defective energy coupling process in the mitochondria. In CN, oxygen is present but its conversion is blocked in the mitochondria (Complex V). By contrast, in VO, oxidative stress is induced via reduction of oxygen (blood) circulation to the occluded brain region. We hypothesize that differential oxygen concentration in both forms of ischemia affect ROS production rate in the mitochondria; thus distinguishing the cytotoxicity pattern for CN and VO. Method: Male, adult Wistar rats (N?=?30) were separated into three groups. A set of n?=?12 animals were treated with orally administered potassium ferricyanide. Global vascular occlusion (GVO) was induced in a second set of animals (n?=?12) using neck cuffs to occlude the common carotid arteries and brachiocephalic vein. The control group (n?=?6) received normal saline for the total duration of the treatment (10 days). Glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA) and acid phosphatase (ACP) levels were assayed in tissue homogenate using colorimetric assay techniques while Cathepsin D (CAD+) was demonstrated through antigen retrieval immunohistochemistry. Data were analyzed in One Way ANOVA with Tukey’s post-hoc test. Significance was set p?Results/Discussion: Cyanide treatment and VO caused a significant rise in SOD; attributed to ROS formation in both forms of ischemia. However, an increase in GSH levels demonstrates mitochondria-ROS production in cyanide treatment while no significant change in GSH was observed in VO versus the control (reduced mitochondria-ROS production). In addition, CN recorded a significant increase in GSH when compared with the control and VO (p?Conclusion: Although CN and VO induced oxidative stress through ROS production, our findings suggest a difference in the threshold of ROS production and cytotoxicity for both forms of ischemia. However, this threshold is dependent on the availability of oxygen to fuel mitochondria-ROS production in oxidative stress. Ultimately, the difference in oxygen availability in vivo determined the significance of lipid peroxidation, calcium-shift and autophagic cell response associated with the ischemia. CN treatment generated more ROS and was associated with prominent cellular changes when compared with VO.     

A STUDY OF EPIDEMIOLOGICAL ASPECTS OF BURN INJURIES

A study was conducted of the epidemiological aspects of 500 fresh cases of burns during the period February to August 1989. Women in the reproductive age group from the lower socioeconomic strata were the most frequently victims (52.8%). Four hundred and thirteen (82.5%) patients sustained accidental burns, 62 (12.4%) were suicidal and 25 (5%) homicidal. Majority (72%) of the accidents occurred as a consequence of garments catching fire. Though most of the subjects wore cotton garments, mortality was higher among those wearing synthetic fabric. Low socioeconomic conditions, overcrowding in the house, floor-level cooking, unsafe cooking appliances and the prevalent clothing pattern stand out prominently as risk factors for burn injury.KEY WORDS: Burns, Epidemiology, Risk factors