Prospective study of serum and aqueous humour anti-Hsp70.1 IgG antibody levels in ocular toxoplasmosis.

AIMS: We evaluate whether the serum and aqueous humour (AH) level of IgG anti-Hsp70.1 antibodies improved the biological diagnosis of ocular toxoplasmosis. METHODS AND RESULTS: In this prospective cross-sectional and multicentre study, serum and AH were collected at the time of active uveitis. Anti-Hsp70.1-antibody levels were determined by ELISA. Patients with confirmed (Group A1, n = 21) or suspected ocular toxoplasmosis (group A2, n = 30) were enrolled, as well as a control group of patients with cataract (group B, n = 42). Serum IgG anti-Hsp70.1 antibody levels were not significantly different within the group of uveitis patients (A1, n = 21 vs A2, n = 30, P = .8) and were significantly associated with the affected retinal zone (P = .006) and with the size of the retinal lesion (P = .03). Serum anti-Hsp70.1 antibody level was positive in 10 out of the 18 patients of group A2. Significant anti-Hsp-70.1 antibody level in AH was reported in only three patients (3 eyes) with confirmed ocular toxoplasmosis. CONCLUSION: While the level of IgG anti-Hsp-70.1 antibody in AH did not improve the laboratory diagnosis of ocular toxoplasmosis, its level in serum was of major significance for retinal damage diagnosis.

A one-step multiplex PCR for acanthamoeba keratitis diagnosis and quality samples control.

PURPOSE: As the number of cases of Acanthamoeba spp. keratitis (AK) is constantly growing, new diagnostic tools are needed to confirm and guide ophthalmologists in this clinically problematic diagnosis. Molecular diagnosis is particularly well adapted, although only a few real-time PCR techniques have been described recently. The aim of this study was to develop a new PCR technique for the diagnosis of AK by combining the detection of Acanthamoeba DNA with human DNA, thus allowing an accurate interpretation of the PCR result. METHODS: Different DNA extraction procedures were compared to ensure an optimized amplification of one Acanthamoeba genome. The analytical parameters of this new multiplex Acanthamoeba beta-globin PCR (MAB-PCR) were evaluated. Fourteen eye drops were tested as potential PCR inhibitors. A prospective series of 28 corneal scrapings was subjected to MAB-PCR. RESULTS: The best extraction procedure associated thermal-shock pretreatment followed by a manual extraction procedure. The MAB-PCR parameters displayed excellent specificity and sensitivity, with a detection of 0.02 genome of Acanthamoeba. No eye drops were total PCR inhibitors. Of 28 corneal scrapings, 18 were considered true negatives. Seven could not be interpreted because of insufficient scraping material. Three were considered true positives: every patient progressed favorably on specific and reliable treatment. CONCLUSIONS: The MAB-PCR is a new tool to diagnose AK. It allows rapid diagnosis and prompt treatment of this probably underestimated etiology of infectious keratitis. This optimized real-time PCR outperforms the gold standard for Acanthamoeba keratitis diagnosis and it allows a concomitant evaluation of the quality of the corneal scraping, which is necessary for a precise interpretation of the results.

Effect of acute increase in blood pressure on intraocular pressure in pigs and humans.

PURPOSE: To study the effect on intraocular pressure (IOP) of a sudden increase in blood pressure (BP) and of changes in partial pressure of CO(2) (pCO(2)). METHODS: Two experimental studies were conducted: in pigs (n = 7), where BP was reduced by intravenous injection of sodium nitroprusside and increased by injection of angiotensin II; and in humans (n = 17 healthy subjects), where BP was increased by two types of isometric exercise (squatting and handgripping) performed for 2 minutes; IOP and pCO(2) were measured every 30 seconds during separate tests (rest, hyperventilation, isometric exercise) and then after 1, 3, 6, and 10 minutes of rest. RESULTS: In pigs, there is a linear relationship between BP and IOP variations: DeltaIOP = 1.21 DeltaBP - 0.14 (P < 0.001). In humans, this linear relationship is as follows: DeltaIOP = 0.40 DeltaBP + 0.85 (P < 0.001) for squatting and DeltaIOP = 0.54 DeltaBP + 0.55 (P = 0.02) for handgripping. BP and IOP increases are greater with squatting than with handgripping (53% vs. 46%, P = 0.05 and 46% vs. 35%, P = 0.03, respectively). Handgripping causes a greater fall in capnia than squatting does (P = 0.02). Capnia and IOP are positively correlated (P < 0.001). CONCLUSIONS: The pharmacological approach in animals and the study of isometric exercise in humans show that IOP rises significantly and rapidly with kinetics close to those of BP, and the two values are linearly related. The absence of variation in capnia and the greater increase in BP during squatting may explain the greater increase in IOP during this exercise compared to handgripping.