Intraocular concentrations of chemotherapeutic agents after systemic or local administration

OBJECTIVES: To investigate the concentrations of carboplatin and etoposide achieved in the aqueous and vitreous humors after intravenous infusion in nonhuman primates, and to investigate whether local administration of carboplatin might result in higher concentrations in the vitreous humor. METHODS: Macaca fascicularis primates were treated with 1 of 3 regimens: (1) intravenous carboplatin (18.7 mg/kg), etoposide (5 mg/kg), and vincristine sulfate (0.05 mg/kg), (2) peribulbar carboplatin (10 mg/mL), or (3) episcleral balloon carboplatin (10 mg/mL). Concentrations of chemotherapeutic agents were measured in the plasma and in the aqueous and vitreous humors. RESULTS: No measurable amount of etoposide was detected in the aqueous or vitreous humor after intravenous administration. Mean measured peak vitreous concentration of carboplatin after intravenous administration was 0.31 microg/mL, which was 1% of the peak plasma value. Mean measured peak vitreous concentrations of carboplatin after peribulbar or episcleral balloon administration were 2.38 microg/mL and 2.95 microg/mL, respectively, which represent 7.68- and 9.52-fold increases over the concentration achieved after intravenous administration. No serious toxic effect was observed in any animal. CONCLUSIONS: Peribulbar and episcleral balloon administration of carboplatin seemed to be safe and resulted in higher vitreous concentrations than intravenous administration in this model. These results suggest that these alternate routes of delivery should be explored in children with vitreous seeding of retinoblastoma.     

Ultrasonographically assessed maximum carotid artery wall thickness in Mexico City residents and Mexican Americans living in San Antonio, Texas. Association with diabetes and cardiovascular risk factors

Measurements of carotid artery wall thickness are often used as a surrogate for atherosclerosis. However, few studies have performed these measurements in populations of Mexican origin. Since Mexicans in Mexico City consume high-carbohydrate diets and have carbohydrate-induced dyslipidemia (high triglyceride and low HDL cholesterol levels) compared with Mexican Americans living in San Antonio, Tex, we questioned whether they also had more atherosclerosis than San Antonio Mexican Americans. Mean maximum intimal-medial thickness (IMT) of the common (CCA) and internal (ICA) carotid arteries were measured in 867 subjects aged 35 to 64 years (40% men) in two Mexican-origin populations, one from San Antonio (n = 202) and the other from Mexico City (n = 665). IMT's in the two cities were compared, and their associations with cardiovascular risk factors were analyzed. Older age, male sex, high levels of total cholesterol, low levels of HDL cholesterol, and high systolic blood pressure were positively associated with both CCA IMT and ICA IMT. Cigarette smoking was significantly associated with ICA IMT. CCA and ICA IMTs in diabetic subjects were thicker than in nondiabetic subjects in both men and women (all P < = .05). CCA IMT was thicker in the San Antonio than the Mexico City subjects after adjustment for cardiovascular risk factors (0.81 versus 0.76 mm in men and 0.77 versus 0.71 mm in women; P < .001 for city difference). San Antonio men also had thicker ICA IMT than their counterparts in Mexico City (0.88 versus 0.83 mm), but the reverse was true for women (0.73 versus 0.77 mm; interaction between sex and city, P < .05). Our results indicate that men had higher carotid IMTs than women. CCA IMT was thicker in San Antonio Mexican Americans than in Mexico City residents. The differences in ICA IMTs between San Antonio and Mexico City were inconsistent. Thus, since Mexico City residents consume high-carbohydrate diets, the data do not support an atherogenic effect of such diets. The interaction between sex and city on ICA IMT deserves further study.     

Ceric-induced grafting of ethyl-acrylate onto sodium alginate

Sodium alginate was graft-copolymerized with ethyl acrylate using ceric ammonium nitrate as an initiator. In order to optimize the conditions for grafting, the concentrations of nitric acid, initiator and monomer together with temperature, time and amount of substrate were varied. The kinetic scheme of free radical graft copolymerization has been proposed and the equations relating the values of rate of polymerization, rate of graft copolymerization and rate of homopolymerization are also suggested. The experimental results agree very well with the proposed kinetic scheme.     

Small bowel transplantation: current progress and clinical application

Total parenteral nutrition (TPN) is used routinely to maintain patients with the Short Bowel Syndrome (SBS). Until recently, TPN has been the only available therapeutic modality for patients with SBS. Currently, it is the treatment of choice for such individuals and occasionally, when the loss of bowel is extensive, it may be the only way of maintaining life. Unfortunately, TPN is expensive and markedly restrains an individual's lifestyle. Despite the overall success of TPN, the numerous risks associated with its use and the many complications of having an intravenous indwelling for years have served as the stimulus for alternative treatments such as small bowel transplantation (SBT). The first attempts at small bowel transplantation in clinical medicine were by Detterling almost 25 years ago. Patient death or graft loss in these early attempts was caused by the failure to control graft rejection and/or the inability to prevent Graft Versus Host Disease (GVHD). A stimulus for renewed clinical interest in SBT was provided by Starzl et al in 1988 with a report of prolonged graft survival without graft rejection or GVHD in a patient who was the recipient of a multivisceral graft consisting of the entire small bowel and other abdominal organs. Since 1964, 78 Small Bowel transplants have been performed in humans. Several variations of the multivisceral procedure in which the liver and the small bowel constitute the major components of the graft were adopted. The longest survival has been in a child who is still alive with a working graft for more than two years, as reported by Goulet from Paris in 1989. The introduction in SBT of the new immunosuppressive agent FK 506 had provided results which are superior to those achieved with Cyclosporine A (CsA). This latter observation prompted the Pittsburgh group to initiate a large series of isolated and composite intestinal grafts. The remarkable results have demonstrated the clinical utility of intestinal transplantation. This paper will try to summarize the history of the small bowel transplantation until the end of the year 1992, with the current progress in use today.     

Plastic deformation of forearm

The unusual occurrence of plastic deformation in an adult is described.