Clinical evaluation of aminocaproic acid for managing traumatic hyphema in children

PURPOSE: The purpose of this study is to determine the incidence of secondary hemorrhage after traumatic hyphema in children and to evaluate the efficacy of epsilon aminocaproic acid in reducing this incidence. METHODS: In a prospective, randomized, double-blind study performed between November 1987 and February 1994, 94 children admitted for traumatic hyphema were assigned to receive either aminocaproic acid (n = 48) (100 mg/kg every 4 hours; maximum, 30 g daily) or placebo (n = 46) for 5 days. Patients who had ingested aspirin in the week preceding admission were excluded from the study. RESULTS: Mean age of the patients was 9.4 years. Black patients comprised 4% of the study population. Secondary hemorrhage occurred in only three patients (3.2%), two from the placebo group and one from the aminocaproic acid group, none of whom had any complications. The duration of hospital stay and the clot resorption times were increased significantly in the aminocaproic acid group (P < 0.001). CONCLUSIONS: The authors report a very low incidence of secondary hemorrhage compared with most previous studies. This difference is likely related to the small proportion of black patients in our study and to the exclusion of patients having ingested aspirin, two factors that seem to be associated with higher rates of rebleeding. The efficacy of aminocaproic acid could not be determined due to the low incidence of hemorrhage. The results of this study, however, suggest that the incidence of secondary hemorrhage in white patients without prior ingestion of aspirin is insufficient to justify routine use of aminocaproic acid in managing traumatic hyphema. Rather, an individualized decision based on the risk factors of each patient would seem more appropriate to avoid a slower clot resorption time and possible side effects of this medication.     

Increased MPTP neurotoxicity in vesicular monoamine transporter 2 heterozygote knockout mice

The neurotoxic action of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been proposed to be attenuated by sequestration into intracellular vesicles by the vesicular monoamine transporter (VMAT2). The purpose of this study was to determine if mice with genetically reduced levels of VMAT2 (heterozygote knockout; VMAT2 +/-) were more vulnerable to MPTP. Striatal dopamine (DA) content, the levels of DA transporter (DAT) protein, and the expression of glial fibrillary acidic protein (GFAP) mRNA, a marker of gliosis, were assessed as markers of MPTP neurotoxicity. In all parameters measured VMAT2 +/- mice were more sensitive than their wild-type littermates (VMAT2 +/+). Administration of MPTP (7.5, 15, or 30 mg/kg, b.i.d.) resulted in dose-dependent reductions in striatal DA levels in both VMAT2 +/- and VMAT2 +/+ animals, but the neurotoxic potency of MPTP was approximately doubled in the VMAT2 +/- mice: 59 versus 23% DA loss 7 days after 7.5 mg/kg dose for VMAT2 +/- and VMAT2 +/+ mice, respectively. Dopaminergic nerve terminal integrity, as assessed by DAT protein expression, also revealed more drastic reductions in the VMAT2 +/- mice: 59 versus 35% loss at 7.5 mg/kg and 95 versus 58% loss at 15 mg/kg for VMAT2 +/- and VMAT2 +/+ mice, respectively. Expression of GFAP mRNA 2 days after MPTP was higher in the VMAT2 +/- mice than in the wild-type: 15.8- versus 7.8-fold increase at 7.5 mg/kg and 20.1- versus 9.6-fold at 15 mg/kg for VMAT2 +/- and VMAT2 +/+ mice, respectively. These observations clearly demonstrate that VMAT2 +/- mice are more susceptible to the neurotoxic effects of MPTP, suggesting that VMAT2-mediated sequestration of the neurotoxin into vesicles may play an important role in attenuating MPTP toxicity in vivo.     

A species of Plasmodium from sandhill cranes in Florida

Infections of a species of Plasmodium (subgenus Giovannolaia) were diagnosed in 3 sandhill cranes (Grus canadensis) from north-central Florida. This parasite is close morphometrically to Plasmodium polare; this finding constitutes the first report of a species of Plasmodium from sandhill cranes in North America.     

Mastication forces and implant-bearing surface

This article discusses the shift of emphasis in implantology from the phenomenon of osseointegration of implants to the accurate fabrication of the prosthesis, recognizing the implant/prosthesis unit as an actual replica rather than a replacement of the missing tooth. The study of kinetics with its succession of mandibular cycles is used to discuss the integration of mastication and occlusion. The importance of periimplant ligament in natural teeth is discussed, along with the impact of its absence on implant mobility. The impact of the bone types and the root surface architecture on the implant-bearing surface is presented along with the stress of the mastication forces. All these factors have to be considered in the treatment planning and effectively communicated to the laboratory. The learning objective of this article is to provide updated information in those areas for the reader.     

Nodular superficial pigmented basal cell epitheliomas

Eradication of multiple nodules, papules, and plaques of pigmented basal cell epitheliomas of the back of one patient was achieved by nine months of daily treatment with 5% fluorouracil cream. Such topical chemotherapy offers the physician an alternative to surgery and radiation in treating patients who have widespread nodular superficial epitheliomas. The need for a prolonged period of treatment and follow-up is emphasized.     

The structure of L-lactate oxidase from Mycobacterium smegmatis

1. An improved purification was developed for L-lactate oxidase from Mycobacterium smegmatis. 2. The mol.wt. of the native enzyme by a sedimentation-equilibrium analysis was 345 000, and other ultracentrifuge methods gave values in the range 345 000-350 000. 3. An amino acid analysis, determinations of protein and flavin, a sedimentation-velocity analysis and an approach to equilibrium analysis gave values for the subunit mol.wt. in the range 43 500-47 000. 4. It was concluded that L-lactate oxidase contains eight subunits of mol.wt. 43 500. 5. Cross-linking of the subunits with dimethyl suberimidate and electron-microscopy studies were consistent with an octameric structure.