Pathogens in early-onset and late-onset intensive care unit-acquired pneumonia.

OBJECTIVES: To compare the type of pathogens isolated from patients with early-onset intensive care unit (ICU)-acquired pneumonia with those isolated from patients with late-onset ICU-acquired pneumonia and to study risk factors for the isolation of pathogens that are potentially resistant to multiple drugs. DESIGN: Prospective cohort study. SETTING: Patients admitted to the ICU of a 677-bed, university-affiliated teaching hospital in Belgium during 1997-2002. METHODS: ICU-acquired pneumonia was defined as a case of pneumonia that occurred 2 days or more after admission to the ICU in combination with a positive results of radiologic analysis, clinical signs and symptoms, and a positive culture result. All cases of pneumonia were categorized as either early onset (within 7 days after admission) and late onset (7 days or more after admission), with or without previous antibiotic treatment, and the corresponding pathogens were analyzed. Risk factors for the isolation of pathogens potentially resistant to multiple drugs (ie, Pseudomonas aeruginosa, Serratia marcescens, Enterobacter species, Morganella morganii, methicillin-resistant Staphylococcus aureus, Citrobacter species, Acinetobacter species, Burkholderia species, extended-spectrum beta -lactamase-producing pathogens, and Stenotrophomonas maltophilia) were analyzed using logistic regression analysis. RESULTS: A total of 4,200 patients stayed at the ICU for 2 or more days, 298 of whom developed ICU-acquired pneumonia, for an overall incidence of 13 cases (95% confidence interval [CI], 11-14 cases) per 1,000 ICU-days. Pathogens potentially resistant to multiple drugs were isolated from 52% of patients with early-onset pneumonia. Risk factors for the isolation of these pathogens were greater age and previous receipt of antibiotic prophylaxis (adjusted odds ratio [aOR], 4.6 [95% CI, 1.6-13.0]) or antibiotic therapy (aOR, 8.2 [95% CI, 2.8-23.8]). The length of ICU admission and hospital stay were weaker risk factors for the isolation of these pathogens. CONCLUSIONS: Pathogens potentially resistant to multiple drugs were isolated in 52% of cases of early-onset ICU-acquired pneumonia. Previous antibiotic use (both prophylactic and therapeutic) is the main risk factor for the isolation of these pathogens.

The phototrichogram: analysis of some technical factors of variation.

Photographic methods for hair evaluation are frequently proposed as an alternative to more invasive methods (trichogram or biopsy). The reliability in terms of quantitative follow-up of hair growth has not been evaluated properly. We report results of comparative studies of scalp hair evaluation with various photographic methods. Statistically significant findings were a better detection of scalp hairs using the original enlargement x 3 as compared to x 2 (212 vs. 167 hair follicles/cm2) and a more acceptable estimate of linear hair growth rate with 'scalp immersion proxigraphy' (SIP) (0.317 mm/day) as compared with classical phototrichogram pictures where this variable was underestimated by 30% on average (0.27 mm/day). SIP-generated linear hair growth rates were very close to the micrometric method (0.37 mm/day). Therefore SIP x 3 images appear preferable for hair growth monitoring during clinical trials.

Comparative evaluation of scalp hair by phototrichogram and unit area trichogram analysis within the same subjects.

Quantitative evaluation of scalp hair requires techniques that are reproducible. The unit area trichogram is such a method but is unsuitable for large-scale clinical trials. An alternative may be the phototrichogram--a non-plucking, non-invasive method. Hair variables were evaluated in 12 Caucasian subjects employing both methods. The mean value for total hair density was significantly underestimated by the phototrichogram (181 versus 237 hairs/cm2); however, no significant difference was found between this phototrichogram value and the number of non-vellus hairs/cm2. Estimates for the percentage of anagen hairs were similar with both methods. Hair diameters from the phototrichogram were too unreliable to be of any practical use. Analysis of the individual hair data revealed that light hair was much more difficult to evaluate than dark hair. Consequently, Caucasian subjects with light hair or dark skin subjects with dark hair should be excluded from studies employing phototrichograms.

Evaluation of dowel space preparation on the apical seal using an image processing system.

The effect of post preparation on the apical seal of endodontically treated specimens was studied. The canals prepared in bovine bone were instrumented and obturated using five obturation techniques: the silver point technique, the lateral condensation of gutta-percha technique, the warm vertical condensation of gutta-percha technique, the Hygenic Ultrafil injection system and the Obtura technique. In addition to these five control groups, the five experimental groups were also subjected to post preparation. In the latter group, the gutta-percha was removed with an engine-driven root canal reamer 48 hours after obturation. Both the control and experimental groups were suspended in a 0.5 per cent crystal violet solution for 48 hours. After dye penetration, the specimens were immersed in liquid nitrogen and then split longitudinally. Linear measurements of the resultant apical dye leakage were determined by image processing. For each obturation technique, all specimens in both the control and experimental groups were recorded if they showed leakage. Using Fisher's exact probability test, it was shown that there was no significant difference between the obturation techniques used.

The flavonoid tangeretin inhibits invasion of MO4 mouse cells into embryonic chick heart in vitro.

Tangeretin, a flavonoid from citrus plants, was found to inhibit the invasion of MO4 cells (Kirsten murine sarcoma virus transformed fetal mouse cells) into embryonic chick heart fragments in vitro. The flavonoid appeared to be chemically stable in tissue culture medium, and the anti-invasive effect was reversible on omission of the molecule from the medium. Unlike (+)-catechin, another anti-invasive flavonoid, tangeretin bound poorly to extracellular matrix. It did not alter fucosylated surface glycopeptides of MO4 cells. Tangeretin seemed not to act as a microtubule inhibitor, as immunocytochemistry revealed no disturbance of the cytoplasmic microtubule complex. However, at anti-invasive concentrations of tangeretin, cell proliferation and thymidine incorporation appeared to be inhibited. When cultured on an artificial substrate, treated MO4 cells were less elongated, covered a larger surface area and exhibited a slower directional migration than untreated cells. From the decrease in ATP content in MO4 cells after tangeretin treatment, we deduce that this flavonoid inhibits a number of intracellular processes, which leads to an inhibition of cell motility and hence of invasion.

Morphometric evaluation of myofibrillar hypoplasia in splayleg piglets.

A morphometric method was applied to evaluate the EMS (extramyofibrillar space) in cross-sections of the musculus adductor as a parameter for the grading of the myofibrillar hypoplasia in splayleg piglets. Although there was a great variability between the individual piglets for the EMS values, a highly significant difference between normal and splayleg piglets was noted. Using this method it was found that myofibrillar hypoplasia indeed is associated with the splayleg syndrome.

Distribution pattern of psoriatic keratoblasts: computer-assisted image-analysis for combined evaluation of DNA synthesis and expression of 67 kD keratin polypeptides in the epidermis of stable plaques of psoriasis.

Psoriatic epidermis is characterized by increased DNA synthesis and disturbed differentiation. Even though these processes are closely associated, most investigations do not give insight into temporal/spatial relationships between both events. We previously developed a double labeling method for the simultaneous demonstration of the germinative and differentiated epidermal compartments in normal human skin by using tritium-labeled thymidine ([3H] Thd) incorporation and immunoperoxidase staining of 67 kD keratin polypeptides. In this paper we report the results of combined evaluation of these compartments in stable plaques of psoriasis. Scanning of skin sections with an automatic image analyzer allows objective quantification of areas of total epidermis, 67 kD+ differentiated epidermis and numbers of [3H] Thdr+ nuclei. Our data indicate that the 67 kD- undifferentiated psoriatic epidermis is expanded. Increased numbers of [3H] Thd+ basal and suprabasal psoriatic keratinocytes are present and most of them (97.9%) pertain to the 67 kD- compartment. Keratin identification in scales taken from the same sites showed a variable but distinct decrease of 67 kD keratin polypeptides. Hence, the hyperplastic epidermis of stable plaques of psoriasis is characterized by the presence of increased numbers of [3H] Thd+ cells, which primarily belong to the undifferentiated (67 kD-) basal and suprabasal compartments, especially in the lowermost parts of the elongated interpapillary rete ridges. These changes are associated with a relative decrease of synthesis of 67 kD polypeptides and the presence in the scales of keratins that confer a characteristic hyperproliferative epidermal keratin pattern to the psoriatic plaque.

Influence of isaxonine on reinnervation of the rat gastrocnemius muscle.

Isaxonine is reported to have a favourable effect on nerve regeneration. The histological and histochemical changes were compared in the gastrocnemius muscles of 20 rats, in which the left sciatic nerve was frozen-crushed for 10 s at the level of the buttock. The animals received a daily dose of intraperitoneal isaxonine and ten others the solvent only. After 8 weeks small type grouping was seen in rats receiving solvent only and large type grouping in rats treated with isaxonine. After 10 weeks a checkerboard pattern of the fibre types was observed in the muscles of animals receiving solvent only but fibre type grouping was present in those treated with isaxonine. This experiment indicates that isaxonine prevents synaptic remodelling by suppression of the redundant nerve endings from additional axons, which have regenerated more slowly, in making contact with motor endplates.

Acid phosphatase activity of cerebrospinal fluid cells in bacterial and abacterial meningitis.

Acid phosphatase staining is performed on cerebrospinal fluid cells of 365 samples from 105 patients with various types of meningitis. This enzyme activity is strongly positive in the early samples of bacterial meningitis, as far as the patients had not received a pretreatment with antibiotics for more than 24 h. It allows monitoring the response to therapy in subsequent samples. Acid phosphatase activity is positive in 2 cases of cryptococcus meningitis. It is negative in all cases of aseptic and Mycoplasma pneumoniae meningitis. The results in herpes encephalitis are variable, depending on the clinical state and the degree of brain destruction. Acid phosphatase staining is a useful and rapid cytological technique for determination of the nature of the meningitis and for monitoring the therapeutical response.

Influence of isaxonine on the target phenomenon, muscle fibre size and neuromuscular junction in the tenotomized and denervated gastrocnemius muscle of the rat.

Isaxonine is reported to accelerate the rate of peripheral nerve regeneration, stimulate axonal sprouting and promote motor and sensory function recovery. The target phenomenon in muscle fibers is the morphological expression of increased stretch activity in a diseased muscle. It can be produced in the gastrocnemius muscle of the rat by tenotomy and is inhibited by simultaneous denervation. The influence of isaxonine on this experimental model was studied. Twenty Wistar rats were submitted to bilateral section of the Achilles tendon and section of the left sciatic nerve. In ten rats, treated with isaxonine, the qualitative and quantitative changes in the gastrocnemius muscle were compared with the control group over a period of 3 weeks. No statistical differences were observed in the occurrence and inhibition of the target phenomenon, the muscle fibre size and the neuromuscular junction. Isaxonine has no direct effect on a diseased muscle with an intact nerve supply, nor in the early stages after complete denervation.

Cerebrospinal fluid cytology in acute ischaemic stroke.

Quantitative and/or qualitative changes in cerebrospinal fluid (CSF) cytology were observed in 31.5% of 225 samples, obtained from patients with recent non-haemorrhagic cerebral infarctions. These changes were variable and did not correlate with the stroke pattern or with the topography of the softening. The CSF cytological abnormalities were statistically different according to the aetiology of the stroke. In those infarctions, due to vasculitis lesions, either of infectious or of auto-immune nature, an abnormal cytology pattern was more frequently observed than in those of atherosclerotic thrombo-embolic origin.

Early changes in experimental denervated rat gastrocnemius muscle. A semi-automatic quantitative study.

Computer-aided image analysis of EM images reveals important morphometric alterations after only 10 days of rat gastrocnemius denervation. The increasing importance of early quantitative changes in human diagnostics is stressed.

Acid phosphatase activity of cerebrospinal fluid cells in leptomeningeal haemorrhage.

One hundred and twenty samples of haemorrhagic spinal fluid were examined by acid phosphatase staining. This enzyme activity starts to appear in mono-histiocytic cells 2 days after bleeding and increases up to the 5th day. After 1 week the activity decreases rapidly. Similar results are found in mixtures of incubated clear spinal fluid, to which blood is added. Acid phosphatase staining is a useful additional method for determination of the age of a leptomeningeal bleed.

Preinduction cervical ripening with prostaglandin E2: influence on psychomotor evolution in the first year.

The long-term effects of elective preinduction of labor at term by extra-amniotic instillation of prostaglandin E2 in methylhydroxyethylcellulose gel were evaluated in 20 children. No untoward effect of this procedure on the neurologic state of the newborn or the psychomotor development of the children during the first 12 months was found.

The use of semiautomatic morphometry in the study of normal rat gastrocnemius muscle fibers.

Based on a fixed number of EM photomicrographs, a semiautomatic image analysis is made of normal gastrocnemius muscle fibers to obtain reference values for comparison with pathologic data. Z disc, mitochondria, tubular system, and sarcoplasmic reticulum are measured. It is stated that no definite fiber type differentiation is possible based on these quantitative data. However, measurements of Z disc and mitochondria are suggestive of such a differentiation. On the other hand, all data reach a Gaussian distribution on a logarithmic scale after a 5% correction factor is introduced.

Influence of stretch on the target phenomenon in the tenotomized and immobilized gastrocnemius muscle of the rat.

The influence of traction on the target phenomenon was analysed in the tenotomized gastrocnemius muscle of Wistar rats. Target fibres were constantly observed at the medial side of the heads of the non-immobilized and tenotomized gastrocnemius muscles used as control. In the muscles fixed in flexion, no target fibres could be detected, while in the muscles fixed in hyperextension some target fibres were seen. The latter were less numerous than those present in the non-immobilized muscles. This experiment proves the importance of stretch mechanisms in the pathogenesis of the target phenomenon.

Inhibition of the target phenomenon in tenotomized rabbit muscle by medullary lesions.

Target fibres were demonstrated in the gastrocnemius muscles following section of the Achilles tendon of two rabbits. In five other animals with tenotomized gastrocnemius muscles, a subarachnoid phenol block of the lumbar and sacral spinal cord was performed. Large and small medullary lesions inhibited the occurrence of target fibres in the tenotomized muscles, the smallest one being neurolysis of the dorsal roots. This final experiment suggests that the target phenomenon is the morphological expression of an increased stretch sensitivity of the tenotomized muscle.

Granulomatous angiitis of the nervous system: a clinicopathological study of one case.

The clinical history is presented of a 69-year-old man with a disease starting with a herpes zoster infection and an acute ascending myelopathy, and ending with an intracerebral hemorrhage. The postmortem examination revealed multiple angiitis lesions, restricted to the central nervous system. In review of the 31 previously described cases there were four other patients in whom the granulomatous angiitis of the nervous system (GANS) was associated with a herpes zoster infection. The relation between both disorders is discussed.