Prognostic markers of sepsis and septic shock

The first stage of systemic inflammatory response during sepsis and septic shock is the massive production of proinflammatory cytokines. Numerous clinical trials were done investigating various agents that were thought to stop this reaction. The results, however, were disappointing. Then it was realised that massive production of antiinflammatory cytokines could also be delirious. Persistent immunosuppression in the course of sepsis increased the risk of death. Therefore the proper balance between pro- and antiinflammatory mediators is extremely important and the methodologies available for monitoring immunological status in patients with sepsis and septic shock are currently of great interest.     

Multi-frequency tympanometry in experimentally-induced cochlear lesions in chinchillas and guinea pigs

OBJECTIVES: To establish that susceptance-conductance tympanograms at a probe-tone frequency of 2 kHz reflects the status of the annular ligament (AL) and through it of the cochlea. METHODS: Experimental study in 5 chinchillas and 22 guinea pigs. Six validating experiments were used: blockages of the stapes and of the round window membrane (RWM), fistula of the RWM, fluid removal from the cochlea, injection of saline in the scala tympani (ST) and acoustic trauma (AT). Quantitative data (mean values of Y226, FR, Y2000, G2000 and B2000) and shape of the curves were analyzed before and immediately after lesions were done. RESULTS: Guinea pig was the most convenient provided bulla was vented and the same tip was used along the experiments. Only the shape of the curves are discriminant: 1/a supplementary sharp peak, centered around negative pressures, is observed in Y/G tympanograms in every case of RWM fistulas and in some case of AT. 2/injection of saline into ST induces immediate and reproducible Y2000, G2000, et B2000 curves modifications. 3/RWM and stapes blockages provoke foreseeable stiffening and sharpening of the tympanograms at 2 kHz. 4/on the contrary, fluid removal from the cochlea induces multiple peaks curves. CONCLUSIONS: Experimentally-induced modifications at the AL either direct (stapes blockage) or indirect by AT or decrease/increase of pressure load at the cochlear interface at the footplate result in noticeable, constant, reproducible changes of curves registered at 2 kHz. The stapes behaves both as the plotter of the curves and the interpreter of the inner ear pressure.     

Calcium phosphate drug delivery system: influence of local zoledronate release on bone implant osteointegration

Despite total hip replacement (THR) gives generally satisfactory results, the quality of outcome in young patients is markedly decreased compared to the average THR outcome. For this population, pharmacological treatment with bisphosphonate would be beneficial to decrease the peri-implant osteolysis. However, as this population does not necessarily suffer from osteoporosis, a nonsystemic treatment would be preferable. Zoledronate was then grafted to hydroxyapatite (HA) coating of titanium implants. The implants were inserted in rat condyles with various zoledronate concentrations. A positive concentration-dependent effect was observed on the peri-implant bone density and on different histomorphometric parameters. Importantly for the outcome of the implants, the mechanical fixation was increased by the local presence of zoledronate. The obtained results open the way of an easy transformation of currently existing HA-coated implants by grafting bisphosphonate onto the coating in order to increase their service life in the patients.     

Cochlear hair cell loss in single-dose versus continuous round window administration of gentamicin

CONCLUSIONS: Gentamicin-induced cochlear hair cell loss depends on local middle ear administration kinetics and the total drug dose. Single-dose gentamicin instillation in the middle ear is associated with a high variation in hair cell loss. OBJECTIVE: To compare the effects of single-dose and continuous round window administration of gentamicin on cochlear hair cell loss in a guinea pig model. MATERIAL AND METHODS: Two methods for drug administration to the inner ear were used. In groups of five animals, a total dose of 0.8 or 3.2 mg of gentamicin was either instilled as a single dose directly into the round window niche or administered continuously over a 1-week period using a pump-catheter system. Continuous administration was achieved by means of a posterior tympanotomy and subcutaneous placement of an osmotic pump fitted with a catheter. The tip of the catheter was fixed in the round window niche. One group of five animals served as controls and received a saline infusion. The animals were sacrificed after 1 week and hair cell loss was determined microscopically after dissection and phalloidin labelling of the basilar membrane and organ of Corti. RESULTS: Quantitation of cochlear hair cell loss revealed a dose-dependent effect of gentamicin. With both treatment modalities the higher dose induced a higher percentage of hair cell loss. There was inner and outer hair cell loss in all four groups that received gentamicin. With the single-dose instillation, hair cell loss was distributed irregularly from the round window membrane towards the cochlear apex, whereas continuous administration induced hair cell loss close to the round window membrane. Single-dose instillation induced greater hair cell loss than continuous administration at the same dose. The inter-individual variation in hair cell loss was highest following single-dose instillation.     

In situ hybridization of dihydroxyacetone phosphate acyltransferase, the regulating enzyme involved in plasmalogen biosynthesis

In situ hybridization can be carried out using different methods. The experimenter has to choose various parameters: the type of tissue fixation, the time of incubation, and the duration of the exposure time. All these parameters are determinant for the sensitivity and the resolution of this technique. This publication of technical aspects described different experiments performed for in situ hybridization on liver tissue. We may conclude on the parameters to optimize each step of the hybridization procedure. Moreover, this technique could be transposed to the brain and applied to little structures with a light expression of DHAP-AT.     

Assays for assessment of sperm DNA integrity: relationships with fertility and conceptus quality

Several assays are available for testing nuclear quality of spermatozoa, many of them allowing to define a DNA fragmentation index (DFI). Numerous recent studies on this subject agree on several points: negative correlations are observed between DFI and sperm characteristics. Concerning the relationships between DFI and artificial reproductive technologies, there are some disagreements about correlations between DFI and fertilization rates; conversely, in case of high DFI, both blastocyst formation rate and pregnancy rate are significantly reduced. Several authors have defined a threshold value for DFI, corresponding to an absence of pregnancy, or a very low pregnancy rate, for samples above this value. Unfortunately, there are no data available concerning the relationships between sperm DNA quality and abnormalities at birth.     

Stress as a trigger of attacks in Menière's disease. A case-crossover study

BACKGROUND: Menière's disease is defined as the presence of recurrent, spontaneous episodic vertigo, hearing loss (HL), aural fullness, and tinnitus. The occurrence of attacks is unpredictable. The etiology is still unknown, but the disease has a pathologic correlate in hydropic distension of the endolymphatic system. Earlier studies have shown increased incidence of stress on the same day as vertigo attacks, but it has not been determined whether stress occurring on the day of the vertiginous episode came before or after the onset of the vertigo. METHODS: A case-crossover study including 46 patients with active Menière's disease. MAIN OUTCOME MEASURE: Relative risks with 95% confidence intervals (CI). FINDINGS: During the study period, 153 Menière's attacks were reported. Twenty-four (52%) of the 46 patients reported attacks. Twelve of the 153 (8%) attacks occurred within 3 hours after exposure to emotional stress. The relative risk of having an attack was 5.10 (95% CI 2.37-10.98) during 3 hours after being exposed to emotional stress. Twenty-nine percent of the patients with attacks had at least one attack after exposure to emotional stress. For mental stress, the relative risk was 4.16 (95% CI 1.46-11.83) and the hazard period 1 hour, but only five attacks were exposed. No excess risk was found after physical stress. INTERPRETATION: Being exposed to emotional stress increases the risk of getting an attack of Menière's disease during the next hour, and the hazard period is possibly extended up to 3 hours.     

Development of the nitric oxide/cGMP system in the embryonic and juvenile pond snail,Lymnaea stagnalis L. A comparative in situ hybridization,histochemical and immunohistochemical study

Recent studies have indicated that nitric oxide (NO)-induced cGMP synthesis is involved in different steps of neurogenesis in invertebrates. The development of putative NO synthetising elements was described earlier in the embryonic and juvenile pond snail, Lymnaea stagnalis, applying NADPH-diaphorase histochemistry (Serfz et al., 1998). In the present study, we examined the distribution of NO synthase (NOS) during Lymnaea development by in situ hybridization for Lymnaea-NOS mRNA, histochemical, and immunohistochemical techniques for the NOS and NO-stimulated cGMP. Peripheral fibers projecting to the CNS and terminating in the ganglionic neuropils showed NOS immunoreactivity from 85% of embryonic development. At the same time, a fine dot-like, immunostaining indicated the presence of cGMP in the neuropil area. In the CNS, Lymnaea-NOS mRNA positive, as well as NOS and cGMP immunoreactive perikarya were detected first during postembryonic development; their number significantly increased from P3 juvenile stage. Some of the cell groups in the CNS containing NOS immunoreactive material also displayed Lymnaea-NOS mRNA hybridization signal and were cGMP-positive. However, in the subesophageal ganglia, the distribution of Lymnaea-NOS mRNA positive cell groups did not correspond to that of the NOS immunoreactive cells. Neurons revealing transient NOS and cGMP immunoreactivity, respectively, could also be detected in this part of the CNS. In most of the ganglia the number of Lymnaea-NOS mRNA containing and cGMP immunopositive neurons, respectively, exceeded that of the NOS immunoreactive cells from P4 juvenile stage. The localization of NADPH-diaphorase reaction also correlated well with that of the NOS immunoreactivity in the developing CNS. At the periphery, colocalization of Lymnaea-NOS mRNA signal, NOS and cGMP immunoreactivities were observed in the epithelial cells of the esophagus and mantle after hatching. The findings suggest the functional maturity of the NO/cGMP signal transduction pathway at both central and peripheral levels during the development of the snail, Lymnaea stagnalis. The differences in the localization of Lymnaea-NOS mRNA labeling and NOS immunoreactivity in the CNS and PNS can be explained by the existence of different NOS isoforms, posttranslational regulation of NOS, and/or some non-specific antibody labeling.