[Phare study. Comparative study of combined cefepime-amikacin versus ceftazidime combined with amikacin in the treatment of nosocomial pneumonias in ventilated patients. Multicenter group study]

OBJECTIVE

To compare the associations of cefepime (2 g x 2/day) + amikacin (7.5 mg.kg-1 x 2/day) (= cefe-ami) and ceftazidime (2 g x 3/day) + amikacin (7.5 mg.kg-1 x 2/day) (= cefta-ami) in patients under mechanical ventilation suffering from a nosocomial pneumonia.

STUDY DESIGN

Multi-centre, open, comparative, randomised study.

PATIENTS

The study included 275 ICU patients enrolled either in the cefe-ami group (n = 141) or in the cefta-ami group (n = 134).

METHODS

All cases were reviewed in a blinded fashion by the steering committee.

RESULTS

Microbiology laboratory tests were positive in 74% of patients of the cefe-ami group and in 63% of the cefta-ami group respectively; 319 presumed causative strains of bacteria were isolated. The mean duration of treatment was 12 days for cefepime, 11 days for ceftazidime and 8 days for amikacin. In intention to treat, the clinical recovery rate was 48.2% in the cefe-ami group and 44.8% in the cefta-ami group respectively. In the population with a documented pneumonia, the clinical recovery was significantly better in the cefe-ami group (53.3%), than in the cefta-ami group (39.3%) (P = 0.05). In per protocol analysis, these rates reached 67.7% in the cefe-ami group and 68.2% in the cefta-ami group respectively. In the bacteriologically documented cases the eradication rates were 86.5% and 89.3% respectively.

CONCLUSION

The efficacy rates of cefe-ami and cefta-ami combinations were similar in ICU patients under mechanical ventilation with a nosocomial pneumonia. However the cefe-ami association was significantly more efficient in the population with a bacteriologically documented pneumonia.

Sufentanil, fentanyl, and alfentanil in head trauma patients: a study on cerebral hemodynamics

OBJECTIVES

To determine the effects of bolus injection and infusion of sufentanil, alfentanil, and fentanyl on cerebral hemodynamics and electroencephalogram activity in patients with increased intracranial pressure (ICP) after severe head trauma.

DESIGN

Randomized, unblended, crossover study.

SETTING

Intensive care unit and trauma center in a university hospital.

PATIENTS

Six patients with head trauma and ICP monitoring, sedated at the time of the study with propofol infusion and full neuromuscular blockade.

INTERVENTIONS

Following a randomized order, in an unblended and crossover fashion, the level of sedation was deepened with a 6-min injection of either sufentanil (1 microg/kg), alfentanil (100 microg/kg), or fentanyl (10 microg/kg) followed by an infusion of 0.005, 0.7, and 0.075 microg/kg/min, respectively, for 1 hr. The three opioids were given to each patient at 24-hr intervals.

MEASUREMENTS AND MAIN RESULTS

Mean arterial pressure (MAP), ICP, cerebral perfusion pressure (CPP), and jugular vein bulb oxygen saturation (Svjo2) were continuously measured and recorded at 1-min intervals throughout the 60-min study period. Sufentanil, fentanyl, and alfentanil infusions were associated with a significant but transient increase in ICP (9+/-2 mm Hg [SD], 8+/-2 mm Hg, and 5.5+/-1 mm Hg, respectively; p<.05). The increase in ICP peaked at 5, 6, and 3 mins, respectively, then gradually decreased and returned to baseline values after 15 mins. This result was accompanied by a significant decrease in MAP (21+/-2 mm Hg, 24+/-2 mm Hg, and 26+/-2 mm Hg, respectively; p<.05) and, thus, in CPP (30+/-3 mm Hg, 31+/-3 mm Hg, and 34+/-3 mm Hg, respectively; p<.05). After 5 mins, MAP and CPP gradually increased, although they remained significantly decreased throughout the study period. No changes in lactate-oxygen index, used as an ischemia index, were observed. Changes in electroencephalogram tracings were characterized by a switch from a fast to a decreased activity, together with an improvement in the background activity.

CONCLUSION

The results of the present study show that alfentanil, sufentanil, and fentanyl produce similar transient increases in ICP when administered by bolus injection in patients with increased ICP. No evidence of cerebral ischemia was observed in the study patients.

Refinement and structural analysis of barnase at 1.5 A resolution

The structure of Bacillus amyloliquefaciens ribonuclease (barnase), an extracellular 110-residue enzyme initially solved at 2.0 A resolution, has been refined at 1.5 A using synchrotron radiation and an imaging-plate scanner. Refinement with anisotropic atomic displacement parameters resulted in increased accuracy of the structure. The final model has a crystallographic R factor of 11.5% and an Rfree of 17.4%. The three independent molecules in the asymmetric unit, referred to as A, B and C, allowed detailed analysis of this final model and meaningful comparison with structures of barnase complexed either with nucleotide inhibitors or with its natural intracellular inhibitor, barstar. The analysis of the overall solvent structure revealed a similar number of water molecules associated with each barnase molecule; among these were 16 equivalent buried solvent molecules, the locations of which are discussed in detail and classified on the basis of their structural role. The importance of the water molecules' contribution to the barnase-barstar interaction is also highlighted. The high accuracy of the present analysis revealed the presence of a Zn2+ ion mediating the contacts between pairs of symmetry-related A, B or C molecules; such an ion had previously only been identified for pairs of C molecules.

Usefulness of spoligotyping in molecular epidemiology of Mycobacterium bovis-related infections in South America

Two hundred twenty-four Mycobacterium bovis isolates, mainly from South American countries, were typed by spoligotyping, and 41 different spoligotypes were identified. A total of 202 M. bovis isolates (90%) were grouped into 19 different clusters. The largest cluster contained 96 isolates (42.8%) on the basis of the most frequently observed spoligotype, spoligotype 34. Nineteen M. bovis isolates from humans in Argentina had spoligotypes and polymorphic GC-rich repetitive sequence (PGRS) types that represented the most common types found among isolates from cattle. All five isolates from Uruguay and three of the six isolates from Paraguay had spoligotypes that were also detected for isolates from Argentina. The spoligotypes of isolates from Brazil, Costa Rica, and Mexico and of some of the isolates from Paraguay could not be found in Argentina. A total of 154 M. bovis isolates were selected in order to compare the discriminative power of spoligotyping and restriction fragment length polymorphism (RFLP) analysis with direct repeat (DR) and PGRS probes. By spoligotyping, 31 different types were found, while AluI-digested DR probe-associated RFLP analysis identified 42 types, and RFLP analysis with the PGRS probe also detected 42 types; these were partly independent of the DR types. By combining the results obtained by spoligotyping and by RFLP analysis with the DR and PGRS probes, 88 different types were obtained. Although the differentiation of M. bovis by spoligotyping was less discriminatory than differentiation by RFLP analysis with the DR and PGRS probes, spoligotyping is easier to perform and its results are easier to interpret. Therefore, for the purpose of typing of M. bovis isolates, spoligotyping could be performed first and the isolates could be grouped into clusters and then analyzed by RFLP analysis with the DR and PGRS probes.

Descriptive anatomy of the human auditory tube

The aim of this study was to correlate current morphologic data relating to the lumen of the auditory tube. Four methods were used: dissection under the operating microscope; microendoscopy of the tubal lumen; optical and electron microscope histology; and MR or CT imaging. The auditory tube consists of two unequal cones, a small posterior third, fixed and osseous (protympanum), and a mobile fibrocartilaginous anterior two-thirds, both joined by the tubal isthmus, a short constriction which is pseudosphincteric at endoscopy. The tensor veli palatini muscle (TVPM) and the levator veli palatini muscle (LVPM) are the chief muscles that vary the tubal lumen of the fibrocartilaginous portion, which is collapsed at rest. CT and especially MR imaging allows their observation in static conditions. Serial histologic sections reveal the continuity between the TVPM and the tensor tympani muscle. The main cartilage framing the lumen varies in shape according to the level surveyed. The tubal mucosa is lined with an epithelium combining ciliated and mucus cells, involved in mucociliary drainage and gas exchanges in the auditory tube. These morphologic elements represent a basis for study of tubal physiology and for planning treatment in dysfunctions of the auditory tube.

Spaceflight hardware allowing unilateral irradiation and chemical fixation in petri dishes

To accommodate a spaceflight experiment with moss (SPM), experiment-unique equipment (EUE) was developed by engineers at Kennedy Space Center. The hardware allows sterile culture for an extended period of time in commercial petri dishes, lateral illumination of each culture with light of a specific wavelength (660 nm; other wavelengths are possible) and a range of intensities (0.05-5 micromoles photons m-2 s-1), incubation in complete darkness, and chemical fixation to terminate the experiment under conditions of microgravity. The use of a fixative required triple containment to protect the astronaut crew. An external panel on the experiment container allowed the timing of illumination and fixation to be controlled by the crew. Light quality is provided by light emitting diodes (LEDs) that are located in the lid of the outer container, the BRIC (Biological Research In Canisters)-LED. Each canister accommodates 6 Petri Dish Fixation Units (PDFUs), and each PDFU holds one 6 cm petri dish. All components are autoclavable. LED illumination is piped through a transparent glass rod. Each PDFU contains fixative in a reservoir that is released by the depression of an actuator. This hardware performed well during its first flight, the 16-day STS-87 mission in Nov./Dec., 1997 as part of the Collaborative USA and Ukrainian Experiment (CUE). It supported vigorous and sterile moss growth, cells were maintained in position and were well-fixed, and there was a vigorous and consistent response to light. Although here used for moss, in future flight experiments this unique new hardware can be used for many types of organisms normally grown in petri dishes, with or without a requirement for illumination.

[Imaging and pathology of the ear and temporal bone (except for the skull base)]

Imaging occupies and increasing place in the investigation of pathological processes of the ear and temporal bone. For some of them (malformations, inflammatory conditions and tumours) the authors detail their indications and results. They conclude that imaging has become increasingly necessary in these conditions, and indispensable not only for choosing the method of treatment but also for medico-legal reasons.

Structural conservation of the transposon Tam3 family in Antirrhinum majus and estimation of the number of copies able to transpose

We have investigated the organization of the transposon Tam3 family in Antirrhinum majus. Genomic hybridization experiments and characterization of 40 independent Tam3 clones isolated from an A. majus plant revealed that the Tam3 family is quite conserved and the copy sizes are uniform. We did not find any copy with a deleted internal sequence, unlike what is usually observed in other transposons. This exceptionally conserved structure of the Tam3 family was confirmed by PCR and sequencing analyses. Sequencing analysis identified eight copies with sequences completely identical to that of the Tam3 transposase gene. These results suggested that a considerable number of autonomous Tam3 copies are present in the genome of A. majus. Among 24 copies which are surrounded by single copy regions of the genome, 14 copies are present as specific insertions in the line which we used, but absent in other lines. These copies are therefore predicted to be movable. If this ratio is the same for all Tam3 copies in a genome, then a maximum of 60% of the copies are estimated to be movable in the genome. The relatively high frequency of gene tagged by Tam3 might reflect the large number of movable copies in the genome.

Human sexuality in long-term care

Sexual expression is a basic human need, a normal part of life that is integral to who we are as human beings. As we age, we continue to be challenged to grow in every area of our lives, including our sexuality. In institutionalized settings, however, human sexuality can be an area in which growth is not fostered, but restrained. Challenges leading to restraint include limited privacy, concerns about the consent of cognitively impaired sexual partners and conflicts with the personal values of institutional staff. Challenges exist in many areas, including inappropriate sexual expression toward a staff member or other residents.

Cellular differentiation in the shoot epidermis

The recent advances in defining genes involved in shoot epidermal cell differentiation are impressive, especially the characterisation of genes involved in cellular patterning. The additional influences of environment and hormones on cellular patterning have recently been emphasised, and important connections have been made to changes in vegetative and reproductive growth phases. Despite these advances the cellular basis for differentiation remains less well defined, but now genetic and cell biological analysis from yeast may provide important models on which to develop further understanding.

[Virtual laparoscopic anatomy of the esophagogastric junction]

The anatomy of the GE junction is represented by computer synthetised pictures. This method allows to represent different organs from different angles, emphasis being put on the laparoscopic angle of vision. This should improve anatomical comprehension. The synthetic pictures have been constructed in a figurative representation. Fatty tissues have been omitted whereas the peritoneal layers covering organs and defining spaces are enhanced.

Bilateral dissection of the internal carotid artery at the base of the skull due to blunt trauma: incidence and severity

Between January 1, 1992 and December 31, 1996, a total of 1095 head trauma vicims were admitted in our intensive care unit. If CT scans demonstrated ischemic brain lesions, arteriography to visualize supraaortic vessels was performed. Carotid artery dissection was observed in ten patients (0.91%) and was bilateral in eight patients (0.73%). In the bilateral carotid artery dissection (BCAD) group, there were five women and three men, with a mean age of 35.2 years (range: 17 to 54 years). Injuries resulted from traffic accidents in seven patients and a fall in one patient. Upon admission, six patients presented with alteration of consciousness and three with hemiplegia or hemiparesia, associated with aphasia in two cases. In two other cases, hemiplegia occurred 24 hr and 13 days after the accident. All patients had brain infarction, which was unilateral in five cases and bilateral in three cases. The severity of lesions was graded on the basis of arteriographic findings as follows: Type I, wall involvement without significant stenosis or dilation; Type II, arterial dissection with stenosis >70% (Type IIA) or dilatation >50% (Type IIB) and the normal diameter of the proximal or distal internal carotid artery; and Type III, thrombosis of the internal carotid artery. Lesions were asymmetrical in six patients, including two with Type II and III lesions and four with Type I and II lesions, and symmetrical in two patients, including one with bilateral Type III lesions and one with bilateral Type II lesions. Surgery was performed in two patients with Type II lesions, including one case associated with contralateral carotid thrombosis. The intrapetrous carotid artery was exposed by an ear-nose-throat (ENT) surgeon and repaired by interposition grafting. Follow-up in these two surgical cases was 28 and 31 months. In the remaining six cases, medical treatment was performed. Outcome in nonsurgical cases was variable: death in two cases at 31 and 43 days after the accident, severe permanent hemiplegia in two cases, and minimal or no sequels in two cases. Following blunt trauma, arteriography of supraaortic vessels should be performed to detect BCAD in any patient with immediate or delayed neurologic symptoms that cannot be explained by CT-scan findings. To better understand the natural course of these lesions and define the indications for surgery, we propose a three-grade classification according to arteriographic findings. If surgery is undertaken, vein grafting should be performed following resection of the carotid artery lesions.

Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants

Several complex phenotypic changes are induced when the transcription factor AmMYB308 is overexpressed in transgenic tobacco plants. We have previously shown that the primary effect of this transcription factor is to inhibit phenolic acid metabolism. In the plants that we produced, two morphological features were prominent: abnormal leaf palisade development and induction of premature cell death in mature leaves. Evidence from the analysis of these transgenic plants suggests that both changes resulted from the lack of phenolic intermediates. These results emphasize the importance of phenolic secondary metabolites in the normal growth and development of tobacco. We suggest that phenolic acid derivatives are important signaling molecules in the final stages of leaf palisade formation and that phenolic acid derivatives also play a prominent role in tissue senescence.

Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants

Several complex phenotypic changes are induced when the transcription factor AmMYB308 is overexpressed in transgenic tobacco plants. We have previously shown that the primary effect of this transcription factor is to inhibit phenolic acid metabolism. In the plants that we produced, two morphological features were prominent: abnormal leaf palisade development and induction of premature cell death in mature leaves. Evidence from the analysis of these transgenic plants suggests that both changes resulted from the lack of phenolic intermediates. These results emphasize the importance of phenolic secondary metabolites in the normal growth and development of tobacco. We suggest that phenolic acid derivatives are important signaling molecules in the final stages of leaf palisade formation and that phenolic acid derivatives also play a prominent role in tissue senescence.

Large surface of cultured human epithelium obtained on a dermal matrix based on live fibroblast-containing fibrin gels

The aim of this study was to develop a new keratinocyte culture system on a dermal equivalent suitable for skin wound closure. Our dermal matrix is based on a fibrin gel from plasma cryoprecipitate containing live human fibroblast (from human foreskin). Keratinocytes obtained from primary culture according to the Rheinwald and Green method, were seeded on the gel at different seeding ratios. In all cases, the keratinocytes plated on the dermal equivalent grew to confluence and stratified epithelium was obtained within 10-15 days in culture. Early expression of basal membrane proteins was detected by immunostaining with laminin and type IV collagen antibodies. Cell proliferation was detected both in the epidermal layer and in the fibroblast embedded in the gel as assessed by BrdU incorporation. Detachment of composite cultures from dishes or flasks is a simple and quick procedure without the need for dispase treatment. Grafting of composite cultures to nude mice gave rise to an orderly stratified, orthokeratinized epithelium resembling human epidermis. A number of advantages including a large expansion factor without the need of 3T3 feeder layer, the availability of fibrin/plasma cryoprecipitate from blood banks and the versatile manipulation of composite cultures suggest that this system could be suitable for the definitive coverage of severely burned patients.

Cerebral vasoconstriction during sustained ventricular tachycardia induces an ischemic stress response of brain tissue in rats

Arterial hypotension can cause cerebral ischemia when the autoregulation of the cerebral circulation is exhausted. We hypothesized that sudden cerebral vasoconstriction induced by moderate hypotensive, but hemodynamically stable, sustained ventricular tachycardias (MHT-VT) further compromises cerebral blood flow (CBF) and induces an ischemic stress response of the brain. CBF-measurements and morphological studies were performed without and with blockade of alpha-adrenergic receptors in order to determine the impact of MHT-VF on brain perfusion and brain tissue. Using a model of MHT-VT, CBF was measured with colored microspheres in 71 rats during control conditions. after the onset of MHT-VT, after the onset of moderate hypotensive hypovolemia (MHH), and after additional non- selective (alpha-blockade with phentolamine and selective alpha1-blockade with prazosin, respectively (0.2-0.4 mg/kg body weight). Plasma catecholamine concentrations were measured in 18 additional rats during control conditions. during MHT-VT and during MHH. The occurrence of heat shock protein (hsp) 72 and activated microglia in the brain was analysed in 18 additional rats in controls, after MHT-VT and MHH. After 20 min of the respective induced hypotension, control conditions were restored for a period of 8 h, by stopping VT or by infusion of isotonic saline solution. CBF was 0.98+/-0.16 (mean+/-S.D.) ml/g/min during control conditions at an arterial pressure of 118+/-13 mmHg, 0.50+/-0.05 ml/g/min (P<0.05 v control) during MHT-VT (76+/-4 mm Hg) and 0.75+/-0.14 ml/g/min (P<0.05 v control and v MHT-VT ) during MHH (71 +/- 8 mm Hg). CBF was better preserved with non-selective alpha-blockade during MHT-VT (0.78+/-0.15 ml/g/min, P<0.05 v MHT-VT and control) as well as with selective alpha1-blockade (0.67+/-0.08 ml/g/min, P<0.05 v MHT-VT and control). Plasma catecholamines were elevated during MHT-VT (P<0.05 v control) but not during MHH (P = N.S. v control). hsp 72 and activated microglia were found in hippocampal regions only after MHT-VT (P<0.05 v control and MHH). These morphological changes were prevented by non-selective alpha-blockade. Stable sustained MHT-VT further reduce the already compromised CBF leading to morphological alterations in the brain which are characteristic of an early ischemic stress response. alpha-Blockade prevents alpha1-adrenergic vasoconstriction and attenuates cerebral hypoperfusion.