Lung infiltrate in a male with a bronchopleural fistula.
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Bronchial Fistula↗
Biomedical subjects
C Raynaud
Publications and source records attributed to C Raynaud.
Analysis of the phthiocerol dimycocerosate locus of Mycobacterium tuberculosis. Evidence that this lipid is involved in the cell wall permeability barrier.
Among the few characterized genes that have products involved in the pathogenicity of Mycobacterium tuberculosis, the etiological agent of tuberculosis, are those of the phthiocerol dimycocerosate (DIM) locus. Genes involved in biosynthesis of these compounds are grouped on a 50-kilobase fragment of the chromosome containing 13 genes. Analysis of mRNA produced from this 50-kilobase fragment in the wild type strain showed that this region is subdivided into three transcriptional units. Biochemical characterization of five mutants with transposon insertions in this region demonstrated that (i) the complete DIM molecules are synthesized in the cytoplasm of M. tuberculosis before being translocated into the cell wall; (ii) the genes fadD26 and fadD28 are directly involved in their biosynthesis; and (iii) both the drrC and mmpL7 genes are necessary for the proper localization of DIMs. Insertional mutants unable to synthesize or translocate DIMs exhibit higher cell wall permeability and are more sensitive to detergent than the wild type strain, indicating for the first time that, in addition to being important virulence factors, extractable lipids of M. tuberculosis play a role in the cell envelope architecture and permeability. This function may represent one of the molecular mechanisms by which DIMs are involved in the virulence of M. tuberculosis.
Base Sequence↗
Oxygenated mycolic acids are necessary for virulence of Mycobacterium tuberculosis in mice.
Members of the Mycobacterium tuberculosis group synthesize a family of long-chain fatty acids, mycolic acids, which are located in the cell envelope. These include the non-oxygenated alpha-mycolic acid and the oxygenated keto- and methoxymycolic acids. The function in bacterial virulence, if any, of these various types of mycolic acids is unknown. We have constructed a mutant strain of M. tuberculosis with an inactivated hma (cmaA, mma4) gene; this mutant strain no longer synthesizes oxygenated mycolic acids, has profound alterations in its envelope permeability and is attenuated in mice.
Animals↗
Inactivation of the antigen 85C gene profoundly affects the mycolate content and alters the permeability of the Mycobacterium tuberculosis cell envelope.
The antigen 85 complex of Mycobacterium tuberculosis consists of three abundantly secreted proteins. The recent characterization of a mycoloyltransferase activity associated in vitro with each of these antigens suggested that they are potentially important for the building of the unusual cell envelope of mycobacteria. To define the physiological role of these proteins, the gene coding for antigen 85C was inactivated by transposon mutagenesis. The resulting mutant was shown to transfer 40% fewer mycolates to the cell wall with no change in the types of mycolates esterifying arabinogalactan or in the composition of non-covalently linked mycolates. As a consequence, the diffusion of the hydrophobic chenodeoxycholate and the hydrophilic glycerol, but not that of isoniazid, was found to be much faster through the cell envelope of the mutant than that of the parent strain. Taken together, these data demonstrate that: (i) antigen 85C is involved directly or indirectly in the transfer of mycolates onto the cell wall of the whole bacterium; (ii) the enzyme is not specific for a given type of mycolate; and (iii) the cell wall-linked mycolate layer may represent a barrier for the diffusion of small hydrophobic and hydrophilic molecules.
Acyltransferases↗
Control by osmotic pressure of voltage-induced permeabilization and gene transfer in mammalian cells.
Cells can be transiently permeabilized by a membrane potential difference increase induced by the application of high electric pulses. This was shown to be under the control of the pulsing buffer osmotic pressure, when short pulses were applied. In this paper, the effects of buffer osmotic pressure during electric treatment and during the following 10 min were investigated in Chinese hamster ovary cells subjected to long (ms) square wave pulses, a condition needed to mediate gene transfer. No effect on cell permeabilization for a small molecule such as propidium iodide was observed. The use of a hypoosmolar buffer during pulsation allows more efficient loading of cells with beta-galactosidase, a tetrameric protein, but no effect of the postpulse buffer osmolarity was observed. The resulting expression of plasmid coding for beta-galactosidase was strongly controlled by buffer osmolarity during as well as after the pulse. The results, tentatively explained in terms of the effect of osmotic pressure on cell swelling, membrane organization, and interaction between molecules and membrane, support the existence of key steps in plasmid-membrane interaction in the mechanism of cell electrically mediated gene transfer.
Animals↗
[Bacterial contamination of eyedrops in clinical use].
PURPOSE: The aim of this study is to assess the importance of bacterial contamination of multidose eyedrops in a routine clinical setting. MATERIAL AND METHODS: 406 eyedrop vials were cultured about one week after clinical use: 204 collected from an Ophthalmic Department, and 202 from a Nursing Home. The microbiological analysis was performed on the tip and the residual eyedrop, counting the number of bacterial colonies. RESULTS: 66 (16.3%) from the 406 analyzed vials were contaminated, and 5.4% out of these were severely affected. There was no significant difference between the "Ophthalmic Department" and the "Nursing Home". Commensal germs were the most frequently encountered in both groups. 4 gram negative organisms were isolated from the "Nursing Home" group. CONCLUSION: These results are in agreement with the literature. Comparison between our two groups is difficult because the eyedrops and uses were different. However, we notice the presence of gram negative organisms in the "Nursing Home". These severe contaminations due to opportunistic pathogen organisms are rare (0.75%), probably underestimated, and represent a real infectious risk during instillation. The study of the contamination site shows that the eyedrop is more often contaminated than the tip. This can be in relation to germ desicsation and to an aspiration phenomenon of contaminated fluid at the tip level. At last, the role of preservatives is not sufficient to ensure the sterility of multidose eyedrops during their use, and this justifies safer (single dose or filtration system) eyedrop vials.
Adult↗
Effect of injection pressure on the success rate of peribulbar block.
The aim of this prospective double-blind study was to evaluate the effect of the pressure on injection of local anaesthetic during peribulbar anaesthesia. Fifty patients scheduled for cataract surgery under peribulbar anaesthesia, with a two injection site technique, were randomly assigned to receive a mixture of 5 ml of etidocaine 1%, 4 ml of bupivacaine 0.5% and hyaluronidase 50 IU, injected under a constant pressure of either 140 g.cm-2 (group 1) or 250 g.cm-2 (group 2). After orbital compression, the degree of akinesia of the extra-ocular and orbicular muscles was graded by clinical assessment. A significantly higher rate of satisfactory akinesia of the extra-ocular muscles was found in group 2 (72% vs 28% in group 1) (p < 0.01). No significant relationship was found between the time taken to administer the anaesthetic mixture at constant pressure and the quality of the block.
Aged↗
[Redox fluorometry study of corneal flavoproteins following hypoxia. Preliminary results].
PURPOSE: The cornea is frequently associated to hypoxia, whether during residence in the heights or more often when wearing contact lenses. To evaluate the corneal modifications induced by hypoxia at an infraclinical stage, we have used redox fluorometry that enables to study in vivo the metabolic response of the cells while measuring the fluorescence of the flavoproteins (FAD) of the corneal cells. METHODS: The variations of the corneal fluorescence were studied in 12 healthy subjects, before and after a topically-induced 5-minute corneal hypoxia, submitting 2 eyes to a prehumidified flow of nitrogen 100%. The results were compared to those found in the same subjects after exposure under the same conditions to an ambiant air flow (N2 = 69%; O2 = 21%). The measurements of the corneal fluorescence were carried out with the fluorophotometre Flurotron Master FM2. RESULTS: The authors did not find any statistically significant difference in the corneal fluorescence between the right and the left eyes of these 12 subjects, whether under normal conditions, under hypoxia, or under air flow (wilcoxon T-test, Friedman test). CONCLUSION: As there are no significant results, these authors suggest that the chosen exposure time, although sufficient in vitro to induce a modification of the fluorecence of the cellular flavoproteins, may be too "short" in vivo. The use of complementary filters with the FM2 system would yield more information. The study of these results led the authors to broaden their search whether by looking for conditions for general hypoxia (hypobarric box) or by increasing local hypoxia (contact lenses).
Adult↗
Functional brain imaging in HIV-1-infected children born to seropositive mothers.
UNLABELLED: The aim of this work was to study cerebral function in vertically infected children with human immunodeficiency virus 1 (HIV-1). METHODS: PET with 18F-labeled fluorodeoxyglucose (FDG) was performed in eight children (2.5-5.5 yr): three with severe neurological symptoms and five without. Quantitative analysis was based on gray matter cortical and subcortical regions of interest for which glucose utilization was measured. RESULTS: Diffuse hypometabolism and subcortical hypermetabolism were found in the three children with severe neurological signs; the five other children had temporo-occipital cortical hypometabolism, mainly on the right side. CONCLUSION: Functional cerebral abnormalities seem to precede clinical symptoms in HIV-1infection of the brain in children.
AIDS Dementia Complex↗
[Bilateral occlusion of the internal carotid arteries. Analysis of a series of 19 patients].
The natural history of patients suffering from bilateral internal carotid occlusion is poorly known. We report a study of 19 patients presenting such a vascular condition as demonstrated by angiography. In all our cases, cardio-vascular risk factors were frequently found. Smoking was particularly frequent and present in 18 patients (95%). Presenting neurological episodes included either transient ischemic attack (8/19) or stroke (9/19). Associated arterial lesions were diffusely distributed on the other cerebral vessels, frequently involving the extra-cranial part of the vertebral arteries. Collateral circulation feeding the intracranial carotid system mainly, or exclusively, originated from the vertebro-basilar system. Ischemic strokes were frequently detected by cerebral CT scan. They were located in the middle cerebral territory or at the junctions between 2 major cerebral arteries. A radiological aspect of cortical atrophy was noted in 9 patients among 19. Regional cerebral blood flow assessed by Xe133 inhalation was usually normal at rest (16/19), but hyporeactivity to acetazolamide was found in 10 patients among 19. The latter was more frequent in patients suffering from arterial hypertension or diabetes mellitus. Our results confirm that the patients suffering atheromatous bilateral occlusion of the internal carotid arteries may survive with minimal neurological deficits. Collateral circulation is mainly provided by the vertebro-basilar system allowing to frequently maintain normal cerebral blood flow at rest.
Aged↗
Dopaminergic D2 receptor SPECT imaging in Rett syndrome: increase of specific binding in striatum.
A dopamine deficiency has been implicated in Rett syndrome, a progressive encephalopathy in girls that involves movement, tonus and cognitive disorders. To test the hypothesis that striatal D2 receptors increase in number in early stages of the disease, we measured the binding potential of 123I-Iodolisuride, a specific D2 ligand, in eleven Rett children aged 4-15 yr (7.9 +/- 3.5 yr) (mean +/- s.d.) and eight control subjects aged 3.5-13 yr (8.1 +/- 3.8 yr) who exhibited other neurological disorders. Regional cerebral blood flow (rCBF) was also measured with SPECT using 133Xe. The binding potential for 123I-ILIS and D2 receptors was significantly higher in Rett (0.45) than in controls (0.23) (p < 0.01). An increase in 123I-ILIS binding due to increased rCBF in patients' striata was excluded. Our results are consistent with a higher density of D2 receptors in young patients suffering from Rett syndrome because of reduced dopaminergic neurotransmission.
Adolescent↗
Regional cerebral blood flow in childhood autism: a SPECT study.
OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.
Autistic Disorder↗
In-vivo SPECT imaging of D2 receptor with iodine-iodolisuride: results in supranuclear palsy.
We assessed the potential use of [123I]iodolisuride (ILIS), a new iodine ergolene derivative, to study human striatal D2 dopamine receptors with SPECT. In normal subjects, we found that the tracer accumulated preferentially in striatum. This was prevented by high doses of haloperidol. The striatal accumulation was maximal between 60 and 180 min after injection. The striatum-to-cerebellum radioactivity concentration ratio as an index of specific binding, measured 60 min after injection, was 1.52 +/- 0.19 (mean +/- s.d.) in controls and 1.36 +/- 0.11 in patients with supranuclear palsy (p less than 0.03). Our results show that ILIS may be used to study D2 receptors with SPECT. In-vivo changes of D2 receptors in human brain may be detected with this method.
Adult↗
Changes in regional cerebral blood flow during brain maturation in children and adolescents.
Regional cerebral blood flow (rCBF) was studied by SPECT using 133Xe in 42 children, aged 2 days to 19 years, considered as neurologically normal. rCBF was measured on cortical regions and on the cerebellum and thalamus. Curves for reference values and standard deviation were defined for each region. At birth, cortical rCBFs were lower than those for adults; after birth they increased until 5 or 6 yr of age to values 50%-85% higher than those for adults and thereafter decreased, reaching adult levels between 15 and 19 yr. Neonatal values of rCBF on cerebellum and thalamus were slightly higher than adult level, but not significantly; after age 1, they followed the common pattern for cortical curves. When rCBFs were expressed in percent global CBF, they were lower at birth than adult levels in the cortex, then increased and reached a plateau corresponding to the adult value before the second year of age. The time needed to reach normal adult values differed for each cortical region. The shortest time was found on the primary cortex and the longest on the associative cortex. Cognitive development of the child seems to be related to changes in blood flow of the corresponding brain regions.
Adolescent↗
A serial study of regional cerebral blood flow before and after hemispherectomy in a child.
Hemimegalencephaly (HME) is a severe unilateral brain malformation the prognosis of which may be improved by hemispherectomy. HME also provides a unique opportunity to compare normal and pathological hemispheric function in the same patient. We performed a serial functional cerebral imaging study in a child suffering from a neuropathologically confirmed left HME. He was hemispherectomized at 11 months because of intractable epilepsy; this led to cessation of seizures and dramatic psychomotor improvement. Regional cerebral blood flow (rCBF) was studied at 1, 7, 10, 12 and 25 months with single photon computed tomography (SPECT) using 133-Xenon and with simultaneous EEG recording. At one month of age SPECT was performed ictally. During left EEG discharges, rCBF was 40% higher on the left hemisphere than on the right, even in occipital and frontal regions, usually immature at this age. A crossed cerebellar hyperperfusion was also found. At 7 and 10 months, SPECT was performed interictally; rCBF was 45% lower in the left hemisphere than in the right. During follow-up, global and regional CBF values showed normal levels and normal maturation in the right hemisphere except for a mild and transient decrease observed one month after hemispherectomy. SPECT provides an additional procedure for studying hemispheric function in vivo. Serial SPECT imaging may be useful for the preoperative and postoperative evaluation in unilateral cerebral malformation.
Brain↗
The role of factor analysis in the evaluation of new radiopharmaceuticals.
Factor analysis of dynamic scintigraphic studies has been proposed for a variety of clinical applications. This method also called FADS (Factor Analysis of Dynamic Structures) enables spatial separation of complex images into discrete factors according to their time/activity characteristics. FADS, which does not require a priori formulation of a compartmental model of tracer kinetics, is particularly suitable for the evaluation of new radiolabeled compounds as potential radiopharmaceuticals. In animals as well as in humans it is possible to obtain information on the spatial time-distribution of tracers by analyzing computer acquired scintigraphic studies. On the basis of data obtained and analyzed with this method using [123I]IMP in humans, dogs, rabbits and rats, with two 99mTc labeled monoclonal antibodies in dogs and with 99mTc DTPA in renal transplants, we recommend this method as an adjunct in radiopharmaceutical development and evaluation.
Amphetamines↗
Regional cerebral blood flow by SPECT imaging in Sturge-Weber disease: an aid for diagnosis.
Regional cerebral blood flow (rCBF) was studied using SPECT (single photon emission computed tomography) with 133-Xenon in 13 patients with confirmed Sturge-Weber disease, aged 9 months to 18 years. CT scan, performed at the same time, showed evident cerebral angioma in 10 but not in three. A marked hypoperfused area was found in all patients, ranging from -32% to -72% and of the same location as the CT signs. The hypoperfusion seems to result from post ictal phenomenon as well as from chronic ischaemia. SPECT imaging is therefore a sensitive method for visualising intracranial angioma in Sturge-Weber disease and it provides an aid for diagnosis when a CT scan is not reliable.
Adolescent↗
SPECT analysis of recent cerebral infarction.
We measured regional cerebral blood flow and [123I]iodoamphetamine (IMP) uptake in 16 patients with unilateral brain infarcts during the subacute period (Day 3 to Day 50) and again after 3 months. Our results show that the central and peripheral areas described earlier in the chronic period were already differentiated in the subacute period. The central area presented a short phase of luxury perfusion and a longer phase of IMP hyperfixation. The peripheral area showed both a slight regional cerebral blood flow decrease and an early IMP uptake decrease similar to those previously found in the chronic period. Contralateral regional cerebral blood flow during the subacute period, considered normal, was significantly lower than that during the chronic period.
Acetazolamide↗