Do oral antibiotics prevent meningitis and serious bacterial infections in children with Streptococcus pneumoniae occult bacteremia? A meta-analysis.

OBJECTIVE: To determine whether oral antibiotics prevent meningitis and serious bacterial infections in children with Streptococcus pneumoniae occult bacteremia. DATA SOURCES: Using the Medline database, the English-language literature was searched for all publications concerning bacteremia, fever, or S pneumoniae from 1966 to April 1996. STUDY SELECTION: All studies that included a series of children with S pneumoniae occult bacteremia containing orally treated and untreated groups. Children were excluded from individual studies if they were immunocompromised, had a serious bacterial infection, underwent a lumbar puncture, or received parenteral antibiotics. DATA EXTRACTION: Three authors independently reviewed each article to determine the number of eligible children and the outcome of children meeting entry criteria. DATA SYNTHESIS: Eleven of 21 studies were excluded, leaving 10 evaluable studies with 656 total cases of S pneumoniae occult bacteremia identified. Patients who received oral antibiotics had fewer serious bacterial infections than untreated patients (3.3% vs 9.7%; pooled odds ratio, 0.35; 95% confidence interval, 0.17 to 0.73). Meningitis developed in 3 (0.8%) of 399 children in the oral antibiotic group and 7 (2.7%) of 257 untreated children (pooled odds ratio, 0.51; 95% confidence interval, 0.12 to 2.09). CONCLUSION: Although oral antibiotics modestly decreased the risk of serious bacterial infections in children with S pneumoniae occult bacteremia, there was insufficient evidence to conclude that oral antibiotics prevent meningitis. Published recommendations that oral antibiotics be administered to prevent serious bacterial infections in children with possible S pneumoniae occult bacteremia should be reevaluated in light of the lower risk of sequelae from S pneumoniae occult bacteremia and newer data concerning side effects from treatment.

Pedicled greater omentum transferred to the spine in a case of postoperative infection.

An alternate surgical treatment was proposed in a case of vertebral postoperative chronic infection. The combination of an anterior omental flap with a posterior internal fixation plus bone grafting was successful, allowing the patient to walk 8 weeks after surgery. This relatively short recovery period compares favorably with the long months of confinement to bed usually required after an all-anterior approach with bone grafting only.

Changes in cell cycle and chromatin distribution in C6 glioma cells treated by dibutyryl cyclic AMP.

C6 glioma cells in culture were treated with 1 mM dibutyryl cyclic AMP (Db-cAMP) for 5, 8, 24 and 72 h. The cells were labelled with [3H]-thymidine before either the end, or the beginning, of the Db-cAMP treatment. The cell cycle passage was monitored by the simultaneous determination of DNA content and DNA synthesis in propidium iodide stained autoradiograms. The data revealed an early (t less than or equal to 3-8 h) and moderate inhibitory effect of Db-cAMP on all phases of the cell cycle except mitosis; some cells (2%) were completely blocked in the S phase. Later (8 less than t less than 24-72 h), the cycling of a substantial part of the population became inhibited in G1 phase. Microdensitometric texture analysis of Feulgen-stained nuclei, performed 24 h after administration of Db-cAMP, showed a higher inhomogeneity of the DNA distribution in cell nuclei, caused by the condensation of a part of the chromatin. This may reflect either changes in genome expression taking part in the process of cAMP induced differentiation or transit of some cells into quiescent G0 or S0 phases.

Gracilis blood supply: anatomical and clinical re-evaluation.

In a review of 20 gracilis flaps in 18 patients, variations in flap viability have been found. In response to these findings, a detailed anatomical study was performed in 15 fresh cadavers. Selective dye injections evaluated the limits of the skin paddle depending on the dominant pedicle. Most of the musculocutaneous perforators were in the upper two-thirds of the gracilis. In one selected application the main blood supply to the skin was recognised to be proximal. Despite the variations in viability, the flap proved to be a versatile and totally adequate tool.

Extensor digitorum brevis as an island flap in the reconstruction of soft-tissue defects in the lower limb.

The extensor digitorum brevis island flap is a versatile and robust flap able to provide adequate bulk and coverage in soft-tissue defects of the lower limb. The donor-site deformity is limited to the necessary scar needed to approach and rotate the muscle. An anatomic study was performed in 10 fresh cadavers and consisted of two parts: study of the muscle flap itself, and examination of skin vascularization. Methylene blue and Salmon's mass (radiopaque) were injected through the three main arteries of the leg. Muscle and cutaneous staining were noted. Clinical applications of this flap are reported. These resulted in successful healing of the defect with good aesthetic and functional results on both recipient and donor sites. Long-term follow-up was maintained for up to 21 months.

Influence of cis-dichlorodiamineplatinum on glioma cell morphology and cell cycle kinetics in tissue culture.

C6 glioma cells (CCL 107) were cultured for three days and then treated with cis-dichlorodiamineplatinum (cis-DDP) at doses of 0.2-10 micrograms/ml medium. Changes in DNA synthesis and DNA content, as well as morphology of cells and chromatin distribution, were examined from the first post-treatment day onwards. The number of cells labelled with [3H]thymidine, detected autoradiographically, decreased after treatment with 0.2-10 micrograms/ml by approximately one half on post-treatment day 1 and diminished further by the third day after treatment. The labelled cells were entirely absent only after treatment with 10 micrograms/ml, 7 days post-treatment. Mitoses decreased from 1.4-0.6% by post-treatment day 1 and completely disappeared by day 3 (1 microgram/ml). Feulgen cytophotometry and propidium iodide cytofluorimetry revealed accumulation of cells in the S-phase, especially the latter part (0.5 and 1.0 micrograms/ml, post-treatment day 1) and subsequently also in G2 phase (post-treatment day 3). Incomplete cyto- and karyokinesis in some cycling cells was indicated by an increased number of binucleate cells and nuclei of higher ploidy classes. Labelled cells with intermediate DNA values were, on average, labelled less intensively, as was revealed by simultaneous measurements of DNA content and [3H]thymidine incorporation. Some cells displayed reduction in grain density over heterochromatin clumps. This would be in agreement with the late S-phase block of DNA replication. After post-treatment day 3 the density of cells in cultures was substantially lower.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer-assisted microfluorometry.

The paper describes an automated microscope fluorometer, based on a Leitz MPV compact system. Automation of the system was provided by an Apple II personal computer thus greatly simplifying operating procedures and increasing measuring speed. The computer system was programmed in BASIC supplemented by a few assembly-level subroutines, necessary for the on-line visualization of results and key-touch control of plot features. Automation resulted in enhancement of measuring precision, due to the greater number of cells that could be analyzed within reasonable time, and to standardization of the measuring procedure itself. Moreover, computer-controlled acquisition made it possible to exploit fast averaging data detection thus enabling the signal-to-noise ratio to be increased and the part of coefficient of variation due to instrumental variability to be diminished. A program for cytophotometric measurements on two separate cell populations from the same slide is described.

Flow cytometric evaluation of proliferative activity and ploidy in myelodysplastic syndromes and acute leukemias.

Propidium iodide (PI) DNA distribution of bone marrow (BM) cells was studied by flow cytometry (FCM) in 36 patients without hematologic or malignant disease (normal BM) and in 172 patients with anemias (36 pts), myelodysplastic syndromes (MDS) (33 pts) and acute leukemia (AL) at diagnosis (60 pts), remission (24 pts) and relapse (19 pts). White blood cells from normal male subjects were used as an external diploid reference standard (median CV = 3.8). Patients with normal BM, anemias, MDS and acute leukemia at diagnosis had tritiated thymidine labeling index (LI) and most with MDS and AL had also evaluable cytogenetics performed on the same BM sample used for FCM. In normal BM, median aliquot of cells with PI-DNA content intermediate between the diploid and the tetraploid value (2n-4n cells %) was 15.7. The ratio between the fluorescence intensity of the G0/1 peak of normal BM cells and the fluorescence intensity of the G0/1 peak of the reference standard (FI ratio) ranged from 93 to 1.05 (mean +/- 2SD). The 2n-4n cell % was higher than normal in anemias (p less than .001), lower in leukemias (p less than .001) and widely scattered in MDS. A linear correlation was found between 2n-4n cell % and LI, with 2n-4n cell % value higher than LI. The FI ratio was lower than normal in anemias (p less than .05), higher in AL with normal cytogenetics (p less than .02) and broadly scattered in MDS with normal cytogenetics. From our experience, PI-DNA-FCM is a simple and adequate method to evaluate proliferative activity in hematologic diseases. Nevertheless, caution must be taken in attributing small changes in FI ratio to aneuploidy, since they are found in anemias and in MDS and AL with normal cytogenetics, possibly due to differences in PI uptake by different cell types.

Propidium iodide staining of cytoautoradiographic preparations for the simultaneous determination of DNA content and grain count.

A new method is described for staining cell nuclei with propidium iodide in preparations that have been processed for autoradiography. The permeability of the stripping film to the dye molecule has been studied, as have the staining conditions, in order to optimize the stoichiometry of the DNA-dye interaction. A procedure has also been set up to allow the simultaneous measurement of DNA content and grain count on the same cell.

DNA content analysis of peripheral blood B-lymphocytes in plasma cell malignancies.

A double fluorescence assay has been employed for the detection of cell surface and/or cytoplasmic immunoglobulins (Ig) and the measurement of nuclear DNA content in the same cell. Following staining for Ig by means of FITC conjugated antibodies directed against heavy or light chains, cell suspensions or cytospin preparations were ethanol fixed and stained with a propidium iodide-RNAse solution. In this way, the cytometric DNA content of circulating B-lymphocytes was analyzed in three patients suffering from plasma cell malignancies with an excess of peripheral blood B-lymphocytes and evidence of aneuploid bone marrow plasma cells. Aneuploid circulating B-lymphocytes with the same DNA stem-line as bone marrow plasma cells were found in two patients with advanced disease but not in the only one we studied at presentation. Aneuploid lymphocytes had surface immunoglobulins bearing the same light chain as the M-protein. In addition, a significant percentage (23%) of cells lacking either surface or cytoplasmic immunoglobulins proved to be aneuploid in plasma cell leukemia. Nuclear DNA measurement combined with surface or cytoplasmic marker analysis appears to be a reliable method for studying neoplastic lymphoid precursor cells in plasma cell malignancies.

Internalization of cycloheptaamylose-dansyl chloride complex during labelling of surface membrane in living Paramecium aurelia cells.

Internalization of cycloheptaamylose-dansyl chloride complex during surface labelling of living long-term starved Paramecium aurelia cells has been observed. This process may be inhibited by pretreatment of the ciliates with dichloroisoproterenol. Uptake of cycloheptaamylose-dansyl chloride may be visualized only after UV preirradiation: the appearance of orange-fluorescing vacuoles of diameter 2.3-4.5 micron may then be observed. Microspectrographic analysis performed on the cells and dansyl derivatives indicates that this fluorescence is produced by a photochemical reaction of dansyl chloride - released from CDC complex inside the digestive vacuoles-under the influence of UV irradiation.

Primary fluorescence of rat muscle after CO2 laser thermal injury.

Observations are reported indicating that CO2 laser radiation induces the appearance of strong primary fluorescence in the tissues surrounding the incidence zone of the beam. The characteristics of this emission were studied by means of cytofluorometric techniques on rat muscles and compared with the fluorescence obtained by a heating procedure or by storage of tissue slices. Laser-induced primary fluorescence was found to be related to the thermal effect of CO2 laser radiation. Moreover, evidence is provided that the processes occurring during heating and those occurring during tissue decomposition most probably produce the same fluorescent products, albeit with different rates. From the results obtained, it is suggested that primary fluorescence can be used as a marker of the damage suffered by the irradiated tissues.

Improvement in microscope photometry by voltage to frequency conversion: analogue measurement and digital processing.

A system for digital measurement of microscope photometric signals, based on Voltage to Frequency Conversion (VFC) and suitable for automatic data processing, has been devised. Advantages and disadvantages are illustrated with special emphasis on the comparison between photocurrent measuring and photon counting techniques. A statistical analysis of the results allows the calibration of VFC net counts versus detected photons. A biological application is reported; this shows the suitability of the system even to low light levels.