Diagnostic accuracy of quantitative EEG to detect delayed cerebral ischemia after subarachnoid hemorrhage: A preliminary study.

OBJECTIVE: Delayed cerebral ischemia (DCI) is the most important and preventable morbidity cause after subarachnoid hemorrhage (SAH). Therefore, DCI early detection is a major challenge. Yet, neurological examination can be unreliable in poor grade SAH patients. EEG provides information from most superficial cortical area, with ischemia-related changes. This study aims at defining an alpha-theta/delta (AT/D) ratio decrease thresholds to detect DCI. METHODS: We used EEG with a montage matching vascular territories (right and left anterior central and posterior) and compared them to follow-up brain imaging. RESULTS: 15 SAH patients (Fischer ≥ 3, World Federation of Neurological Surgeons scale ≥4, 9 DCI) were monitored during 6.4 [4-8] days (min = 2d, max = 13d). AT/D changes could follow three different patterns: (1) prolonged or (2) transient decrease and (3) no decrease or progressive increase. A regional 30% decrease outlasting 3.7 h reached 100% sensitivity and 88.9% specificity to detect DCI. Only 22.6% were in a zone of uncertain diagnosis (3.7-8.04 h). These prolonged decreases, with a loss of transient changes, started in cortical areas evolving toward DCI, and preceded intracranial changes when available. CONCLUSION: Although this study has a small sample size, prolonged AT/D decrease seems to be a reliable biomarker of DCI. SIGNIFICANCE: cEEG changes are likely to precede cerebral infarction and could be useful at the bedside to detect DCI before irreversible damage.

[Analysis and treatment of a patient with bilateral pthiriasis palpebrarum]. / Analyse iconographique et prise en charge d'une pthiriase ciliaire bilatérale.

OBSERVATION: a 41-year-old man presented to the ophthalmologic emergency department with ocular burns. The examination showed many parasites at several stages of the parasitic cycle. The parasitologic analysis found many Pthirus pubis in the eyelids. The dermatological consultation determined that other locations were affected and sought other sexually transmitted diseases and also detected other exposed patients. The detailed clinical examination determined the type of ectoparasite concerned and noted the various phases of its parasitic cycle. The differential diagnosis with Pthirus capitatis can be difficult and its treatment is different. Precise knowledge of the various ectoparasites provided the diagnosis. Screening for sexually transmitted diseases and investigations of the subjects' contacts were essential. CONCLUSION: the diagnosis of pthiriasis is easy at an advanced stage; however, it could be more difficult at earlier stages. Its treatment is not often familiar to the ophthalmologist. Eradicating pthiriasis without investigating other sexually transmitted infections as well as the subjects' contacts could have more serious consequences on public health.

Chromosome aberrations and cell inactivation induced in mammalian cells by ultrasoft X-rays: correlation with the core ionizations in DNA.

PURPOSE: To study the frequency of chromosome aberrations induced by soft X-rays. To see if the core ionization of DNA atoms is involved in this end-point as much as it appears to be in cell killing. MATERIALS AND METHODS: V79 hamster cells were irradiated by synchrotron radiation photons iso-attenuated in the cell (250, 350, 810eV). The morphological chromosome aberrations detected in the first post-irradiation cell division (dicentrics and centric rings) were studied by Giemsa staining. RESULTS: The chromosome aberrations at 350eV were, respectively, 2.6 +/- 0.8 and 2.1 +/- 0.8 times more numerous than at 250 and 810eV for the same average dose absorbed by the nucleus. These relative effectivenesses are comparable with the ones already measured for cell killing. Moreover, they roughly vary such as the relative numbers of core ionizations (including in the phosphorus L-shell) produced in DNA and its bound water (water being involved only at 810eV through the oxygen atoms). In particular, they reproduce the characteristic twofold enhancement at 350eV, above the carbon K threshold. CONCLUSIONS: Correlations suggest that the core ionization process is likely a common and essential mechanism initiating both chromosome aberration and cell killing end-points at these photon energies.

[Toxoplasma gondii and necrotizing retinitis: a case report]. / Rétinite nécrosante à Toxoplasma gondii: à propos d'un cas.

Toxoplasmic retinochoroiditis is an important opportunistic retinal infection in immunodeficiency and elderly patients. The diagnosis of toxoplasmic retinochoroiditis is based primarily on characteristic ocular findings, with supportive serological evidence. It may present as diffuse necrotizing retinitis instead of a focal lesion. We report the original case of a 74-year-old woman who presented with blurred vision in her left eye lasting 3 months. In her medical history, the patient described a tuberculous infection evolving for some months, as well as agranulocytosis treated with Rifadine. Fundus examination revealed diffuse necrotizing retinitis, mainly at the nasal quadrant, with marked vitreitis in the left eye. Clinical recognition of atypical presentations is critical for timely antiparasitic drug therapy. This case initially was misdiagnosed as acute retinal necrosis syndrome. The correct diagnosis was confirmed by response to polymerase chain reaction studies of an intraocular specimen and histopathological analysis. The extensive necrotizing retinitis was nonhemorrhagic but associated with retinal detachment. Significant visual loss accompanied the infection. Toxoplasmosis should be considered as a cause of diffuse necrotizing retinitis in elderly and immunosuppressive patients. Older patients may be more susceptible to severe ocular Toxoplasma infections because of age-related decline in cell-mediated immunity and chronic underlying diseases.

Biological effects induced by K photo-ionisation in and near constituent atoms of DNA.

In order to assess the lethal efficiency and other biological effects of inner shell ionisations of constituent atoms of DNA ('K' events), experiments were developed at the LURE synchrotron facility using ultrasoft X rays as a probe of K events. The lethal efficiency of ultrasoft X rays above the carbon K threshold was especially investigated using V79 cells and compared with their efficiency to induce double strand breaks in dry plasmid-DNA. A correlation between the K event efficiencies for these processes is shown. Beams at 340 eV were found to be twice as efficient at killing cells than were beams at 250 eV. In addition, a rough two-fold increase of the relative biological effectiveness for dicentric + ring induction has also been observed between 250 and 340 eV radiations.

Cell inactivation and double-strand breaks: the role of core ionizations, as probed by ultrasoft X rays.

The large RBE (approximately 7) measured for the killing of Chinese hamster V79 cells by 340 eV ultrasoft X rays, which preferentially ionize the K shell of carbon atoms (Hervé du Penhoat et al., Radiat. Res. 151, 649-658, 1999), was used to investigate the location of sensitive sites for cell inactivation and the physical modes of action of radiation. The enhancement of the RBE above the carbon K-shell edge either may indicate a high intrinsic efficiency of carbon K-shell ionizations (due, for example, to a specific physical or chemical effect) or may be related to the preferential localization of these ionizations on the DNA. The second interpretation would indicate a strong local (within 3 nm) action of K-shell ionizations and consequently the importance of a direct mechanism for radiation lethality (without excluding an action in conjunction with an indirect component). To distinguish between these two hypotheses, the efficiencies of core ionizations in DNA atoms (phosphorus L-shell, carbon K-shell, and oxygen K-shell ionizations) to induce damages were investigated by measuring their capacities to produce DNA double-strand breaks (DSBs). The effect of photoionizations in isolated DNA was studied using pBS plasmids in a partially hydrated state. No enhancement of the efficiency of DSB induction by carbon K-shell ionizations compared to oxygen K-shell ionizations was found, supporting the hypothesis that it is the localization of these carbon K-shell events on DNA which gives to the 340 eV photons their high killing efficiency. In agreement with this interpretation, cell inactivation and DSB induction, which do not appear to be correlated when expressed in terms of yields per unit dose in the sample, exhibit a rather good correlation when expressed in terms of efficiencies per core event in the DNA. These results suggest that core ionizations in DNA, through core-hole relaxation in conjunction with localized effects of spatially correlated secondary and Auger electrons, may be the major critical events for cell inactivation, and that the resulting DSBs (or a constant fraction of these DSBs) may be a major class of unrepairable lesions.

Lethal effect of carbon K-shell photoionizations in Chinese hamster V79 cell nuclei: experimental method and theoretical analysis.

To test a possible specific effect of carbon K-shell ionizations in DNA, survival curves for Chinese hamster V79 cells were measured for X irradiations at energies below and above the carbon K-shell ionization threshold. Specific values of the X-ray energies (250 and 340 eV) were chosen to ensure isoattenuation of the two kinds of radiation within the cell. An enhancement of lethality by a factor of about 2 was found for X rays at 340 eV compared to below the threshold at 250 eV. This may be attributed to the production of highly efficient carbon K-shell ionizations located on DNA. A model of X-ray lethality (Goodhead et al., Radiat. Prot. Dosim. 52, 217-223, 1994) was extended to allow for a possible lethal effect from clusters of reactive species induced by K-shell photoionizations (K-shell clusters). Within this model, the increase in lethality above the carbon K-shell threshold may be explained by a value of 2% for the lethal efficiency of K-shell clusters overlapping the DNA. An extrapolation to the lethal effect of more complex ion-induced K-shell ionizations indicates that K-shell ionization may be a major process in the biological effectiveness of heavy ions.

Infectious discitis diagnostic contribution of laboratory tests and percutaneous discovertebral biopsy.

Clinical and laboratory findings in 120 patients with suspected discitis (loss of disk height and erosions of the vertebral endplates on plain radiographs) were reviewed and compared with percutaneous discovertebral biopsy results. Patients were categorized into three groups based on whether the symptoms developed after an invasive procedure (Group I), during septicemia (Group II), or spontaneously (Group III). Group II patients were more likely to have fever and had higher mean erythrocyte sedimentation rate and C-reactive protein values. A pathogen was recovered in the biopsy specimen in 34%, 60.7%, and 43.5% of patients in groups I, II, and III, respectively. Specific histologic changes were seen in 49%, 42.8%, and 51.3% of cases, respectively. The combination of clinical, laboratory test, and biopsy findings established the diagnosis of pyogenic discitis in 74 cases (62.5%), tuberculous discitis in nine cases (7.5%), and degenerative pseudodiscitis in 37 cases (30%). Percutaneous biopsy had a sensitivity of 72% and a specificity of 94%. Percutaneous discovertebral biopsy is helpful for the diagnosis of infectious discitis and should be done whenever this condition is suspected.

[Search for bacterial contamination of the aqueous humor during cataract surgery with and without local antibiotic prophylaxis]. / Recherche d'une contamination bactérienne du liquide intra-oculaire au cours de la chirurgie de la cataracte avec et sans antibioprophylaxie locale.

PURPOSE: Bacterial contamination of anterior chamber at the end of cataract surgery, was compared between two techniques: extracapsular extraction and phacoemulsification. The effectiveness of preoperative antibiotic eyedrops using Norfloxacine 0.3% (Chibroxine) was also evaluated. METHOD: The study focused on 101 patients grouped according to surgical technique and presence of preoperative antibiotic eyedrops. Conjunctival sampling was made the day prior the surgery, as well as in the operating room, after skin and conjunctival desinfection with povidone iodine in all the patients included in the study. Aqueous humour was collected at the end of surgery. RESULTS: Eight samples out of 101 were positive which represents 7.9% of the cases. In 75% of the cases, the anterior chamber aspirate showed a different germ or non-recurrent germ in the second conjunctival sample. None of the included patients developed endophthalmitis. The two most frequent pathogens were Propionibacterium acnes in 62.5% of the cases, and Staphylococcus epidermidis in 50%. Another pathogen was found in a culture environment: Micrococcus roseus. In two samples, two different bacteria grew: Propionibacterium acnes and Staphylococcus epidermidis. Whatever the surgical technique, no statistically significant bacterial contamination was found. There was no significant statistical difference between patients who had local antibiotic eyedrops and those who did not. CONCLUSION: This study confirms the poor reliability of local antibiotic eyedrops to prevent surgical contamination. Furthermore performing an anterior chamber aspirate at the end of the surgery for risk patients would help the physician identify the pathogens involved in endophthalmitis in order to begin antibiotic treatment as soon as possible.

[Effects of laser chorioretinal photocoagulation]. / Les effets de la photocoagulation chorio-rétinienne au laser.

Laser-chorioretinal interactions depend on: non controllable parameters: spectral transmission, absorption of tissue, scattering of laser, distribution of ocular chromophores, thermal conductivity of tissue. They are important determinant of laser tissue effects. parameters that can be monitored by the physician: size of the spot, pulse duration, laser energy and laser wavelengths. Theoretical predictions of laser-tissue interaction with the choroid and the retinal agree with histological and clinical data. The choice of physical parameters of laser must be done in order to prevent adverse effects as to obtain researched therapeutic goal.