Unusual Toxoplasma infection of the eye and central nervous system in an HIV-positive patient.

OBJECTIVE: To report on a unique combination of cerebral toxoplasmosis and ocular toxoplasmosis in an HIV-positive patient in Slovakia. METHODS: A 35-year-old heterosexual patient who presented with headache and major seizures underwent computed tomography (CT) and magnetic resonance imaging (MRI). Based on clinical findings, serological tests for toxoplasmosis were performed on serum and ocular fluid specimens. PCR was also used to detect Toxoplasma gondii and cytomegalovirus DNA. Goldmann and Witmer coefficient calculation was applied to demonstrate the synthesis of intraocular IgG antibodies. RESULTS: CT and MRI revealed cystic lesions suspected of metastasis in the occipital and temporal regions, and we searched for the primary tumor. After vision loss in the left eye, which rapidly progressed to complete blindness, an eye examination detected macular edema. Anti-edema treatment was initiated. HIV positivity with a very low CD4 T-cell count (20/μL) was found, and the viral load was 100 400 HIV-RNA copies/ml. The serum was positive for anti-Toxoplasma IgG antibodies (> 200 IU/mL), IgM negative, and IgA borderline. As toxoplasmic encephalitis and retinitis were suspected, antitoxoplasmic therapy with pyrimethamine, spiramycin, and folinic acid was started. The ophthalmologist considered cytomegalovirus retinitis, which was not confirmed by serology or PCR. In contrast, the presence of IgG antibodies in ocular fluid and serum with the calculation of the Goldmann-Witmer coefficient (GW = 32) as well as PCR DNA positivity pointed to Toxoplasma gondii as the etiological agent. Follow-up MRI scan confirmed regression of the pathological lesions, neurological deficit also improved, CD4 T-lymphocytes increased above 200/μL, but blindness of the left eye persisted. CONCLUSION: CT and MRI scans offered no clue as to Toxoplasma etiology of the brain and eye involvement in an HIV-positive patient, which was only confirmed by laboratory tests. Due to the delay in the diagnosis of toxoplasmosis, time from the epileptic seizure to treatment initiation was 16 days, which assumedly caused irreversible blindness in the patient.

Gas chromatographic determination of benzene, toluene, ethylbenzene and xylenes using flame ionization detector in water samples with direct aqueous injection up to 250 microl.

A simple method of solventless extraction of volatile organic compounds (benzene, toluene, ethylbenzene and xylenes) from aqueous samples was developed. This method allows direct injection of large volume of water sample into a gas chromatograph using the sorption capacity of the sorbent Chromosorb P NAW applied directly in the injection port of gas chromatograph. The system prevent water penetration into a column, keep it adsorbed on its surface until the analytes are stripped into a column, and the residual water is purging using split flow. The limit of detection ranging from 0.6 for benzene to 1.1 microg l(-1) for o-xylene and limit of quantification ranging 2.0-3.6 microg l(-1) are lower that those reached by gas chromatography with flame ionization detection and direct aqueous injection before.

Gas chromatography-mass spectrometry-Fourier transform infrared spectrometry and high-performance liquid chromatographic characterization of mononitro- and dinitro-isomers from the nitration of N,N-dimethyldiphenylacetamide.

Gas chromatographic retention data, Fourier transform infrared and mass spectrometric (electron impact, electron attachment and methane chemical ionization) profiles are reported for the products of mono- and dinitration of N,N-dimethyldiphenylacetamide. Differentiations of analytical importance among isomers could be gathered by the study which led to their complete identification.