Dracunculus Species in Meso-mammals from Georgia, United States, and Implications for the Guinea Worm Eradication Program in Chad, Africa.

The prevalence and diversity of parasitic nematodes in wildlife have been well studied for certain species, yet for others considerable gaps in knowledge exist. The parasitic nematode Dracunculus insignis infects North American wildlife, and past research on this species has led to an increased understanding of the potential host diversity and transmission of the closely related human Guinea worm, Dracunculus medinensis (which is currently the focus of a global eradication program). Many definitive hosts have been documented for D. insignis; however, the life cycle has been studied only in laboratories, and only a single phylogenetic study has been conducted on D. insignis (from Canada). The goals of the present study were to investigate the prevalence of infections with Dracunculus species among wildlife at a single site (Di-Lane plantation) in the southeastern United States, evaluate the genetic diversity of parasites at this site, and investigate potential paratenic hosts that may be involved in transmission. Over 3 yr, we sampled 228 meso-mammals, reporting an overall prevalence of infection with Dracunculus insignis of 20% (46/228). Amphibians and fish were sampled in the same geographic area as infected meso-mammals. Dracunculus insignis third-stage larvae were recovered from 2 different species of amphibians, but all fish sampled were negative. Phylogenetic analysis of the partial cytochrome c oxidase I (COI) gene showed very little diversity of Dracunculus at Di-Lane; however, we did recover a single nematode from a Virginia opossum (Didelphis virginiana) that falls outside of the D. insignis clade, more closely aligns with Dracunculus lutrae, and may represent an undescribed species. This work documents the occurrence of D. insignis in frogs, a potential transmission pathway for D. insignis at a single geographic site in nature. When applied to the global Guinea Worm Eradication Program, and Chad, Africa, in particular, this work increases our knowledge of the potential role of aquatic animals in the transmission of Dracunculus species and informs on potential intervention strategies that may be applied to the eradication of Guinea worm in Africa.

Canarypox virus expressing wild type p53 for gene therapy in murine tumors mutated in p53.

The antitumor activity of a recombinant canarypox virus expressing wild type murine p53 (ALVAC-p53) was investigated in two murine syngeneic tumors harboring an endogenous p53 mutation (CMS4 and TS/A). Direct intratumor injections of ALVAC-p53 in CMS4 pre-established subcutaneous tumors induced total tumor regression in 66% of mice. Furthermore, 100% of the cured mice was protected against a contralateral subsequent challenge with the parental tumor cells. The intravenous treatment of experimental lung metastasis by ALVAC-p53 also induced significant tumor growth inhibition in both models. The antitumor effect of ALVAC-p53 was only observed in immunocompetent animals and was associated with the generation of a specific antitumor immune response. ALVAC-p53 induced the expression of a functional p53 wild type protein as demonstrated by up-regulation of p21waf1 and induction of apoptosis. A vaccine strategy using intravenous or subcutaneous ALVAC-p53/NYVAC-p53 prime boost protocol failed to induce CTL against p53 wild type used as target tumor antigen, and failed to protect mice against challenge with the mutated tumor cells. The mechanism of the curative and protective effects observed after direct intratumor injections results from the induction of a specific antitumor response directed against other antigens than p53. Our results suggest that the local induction of tumor apoptosis, combined with the adjuvant effect of ALVAC vector, enhances the immunogenicity of the intratumor environment and allows induction of specific antitumor immune response.

Canarypox virus-mediated interleukin 12 gene transfer into murine mammary adenocarcinoma induces tumor suppression and long-term antitumoral immunity.

The antitumoral activity of recombinant canarypox virus vectors (ALVAC) expressing murine interleukin 12 (IL-12) was evaluated in the syngeneic, nonimmunogenic murine mammary adenocarcinoma model (TS/A). Seven-day preestablished subcutaneous tumors (5- to 6-mm mean diameters) were injected on days 7, 10, 14, 17, 21, and 24 with the vector ALVAC-IL12 at 2.5 x 10(5) TCID50 (50% tissue culture infective dose). Total tumor regression occurred in 40 to 50% of the treated mice. Furthermore, 100% of the cured mice were protected against a contralateral subsequent challenge with the TS/A parental cells on day 28. The ALVAC-IL12 treatment is not effective in nude mice, suggesting the critical role of T cells. CD4 and CD8 T cells infiltrated the tumors treated with ALVAC-IL12 in the BALB/c model. Furthermore, in vivo depletion of CD4+ T cells totally abrogated the induction of the long-term antitumoral immune response by ALVAC-IL12. Interestingly, some tumor growth inhibition was also observed with ALVAC-betaGal treatment and a vaccinal effect was found in 33% of the treated animals, suggesting an adjuvant effect of the vector itself. Other ALVAC vectors expressing murine cytokines (IL-2, GM-CSF, IFN-gamma) were evaluated in the same model. Major antitumoral activity was observed with ALVAC-GM-CSF. However, a combination of ALVAC-GM-CSF and ALVAC-IL12 had no synergistic effect. These results suggest that in vivo gene transfer with canarypox virus expressing IL-12 may provide an effective and safe strategy for the treatment of human cancers.

Angle closure glaucoma precipitated by aerosolized atropine.

Angle closure glaucoma is an infrequent form of glaucoma occurring when the filtration mechanism for the aqueous humor is obstructed by apposition of the peripheral iris to the trabecular meshwork. Anatomic features associated with acute-angle closure include congenitally small anterior segments, increased lens thickness, and shallow anterior chamber depth. We present two patients who developed signs and symptoms of angle closure glaucoma after receiving aerosolized atropine for treatment of chronic obstructive pulmonary disease. We recommend that before instituting therapy with an inhaled anticholinergic agent, the patient should be questioned concerning prior history of angle closure glaucoma symptoms and signs and the anterior chamber depth should be examined using iris illumination. Patients having shallow anterior chambers, or possible prior angle closure glaucoma attacks, should be examined by an ophthalmologist before inhalant anticholinergic therapy.

Asteroid hyalosis and axial length measurement using automated biometry.

Accurate axial length measurements are needed before intraocular lens implantation in patients with asteroid hyalosis requiring cataract extraction. We suspected that falsely short axial length measurements may be obtained using automated A-scan biometry when we found an automated measurement of 15.90 mm in a patient with severe unilateral asteroid hyalosis. A manual biometry measurement of 21.90 mm was obtained for comparison; this was within 0.2 mm of the manual reading in the opposite uninvolved eye. A case-control study was performed on 20 unilateral asteroid hyalosis subjects using the uninvolved eye as the control, comparing automated biometry and manual A-scan biometry to assess the effect of asteroid hyalosis on automated biometry measurements. Five subjects (25%) with asteroid hyalosis had falsely short axial length measurements of more than 1.00 mm using automated biometry. This would result in more than 2.50 diopters of error in the implanted lens power. This case-control study demonstrates that falsely short axial length measurements may be obtained using automated biometry in patients with asteroid hyalosis, leading to significant error in intraocular lens power calculations.

Adrenergic influence on iris stromal pigmentation: evidence for alpha-adrenergic receptors.

Adrenergic influence on iris pigmentation in newborn pigmented rabbits was studied. Selective adrenergic antagonists were used topically to determine whether they could inhibit iris pigmentation. Unilateral, topical administration of an alpha-adrenergic antagonist (thymoxamine hydrochloride 1/2%) was not associated with iris hypochromia. Adrenergic influence on iris stromal melanogenesis appears to be mediated by alpha-adrenergic receptors.