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Biomedical subjects

P Thomas

Publications and source records attributed to P Thomas.

At least 325 records · Page 18Linked to original sources
PubMed1999

[Infection of submucosal tumor after endosonography-guided needle biopsy].

Endosonography fine needle guided aspiration (EUS-FNA) biopsy is an interesting technique for the diagnosis of suspected gastrointestinal lesions, and is rarely complicated by infection. We report one case of severe infection after EUS-FNA of benign oesophageal leiomyoma, leading to an oesophagectomy. Recent studies about this technique described only infectious complications after biopsy of cystic lesions. They also show that EUS-FNA may misdiagnose leiomyosarcoma. Our report confirms these data, and relates a hitherto non-reported complication, i.e. the infection of a non-cystic lesion.

Abscess↗
PubMed1999

[Absence status epilepsy].

Absence status (AS), or "Petit Mal status" is a polymorphic condition that can complicate many epileptic syndromes. Diagnosis is difficult on the basis of clinical semiology alone, and requires emergency EEG. Although heterogeneous, the most typical ictal pattern is constituted by slow generalized rhythmic spike-waves (SW) or polyspike-waves (PSW) complexes. In a number of cases, clinical and EEG normalization is obtained after intravenous (i.v.) benzodiazepine (BZ) injection. In some difficult cases, neuropsychological investigations before and after BZ injection is useful: a significant improvement of the neuropsychological score should occur following BZ injection. On a nosographic point of view, literature data indicate that 4 types of AS may be recognized. Typical AS occurs as part of an idiopathic generalised epilepsy most often characterized by absences. Isolated impairment of consciousness, at times with subtle jerks of the eyelids, is the essential symptomatology. The EEG correlates with repetitive absence seizures and shows symmetric and bilateral synchronous SW or PSW complexes faster than 3 Hz. The immediate prognosis is excellent. Atypical AS occurs in patients with symptomatic or cryptogenic generalized epilepsies and is characterized by a fluctuating confusional state with more prominent tonic and/or myoclonic and/or lateralized ictal manifestations than occur in typical AS. The EEG shows continuous or intermittent diffuse irregular slow SW or PSW complexes. The immediate prognosis is guarded, as these episodes tend to recur and to be resistant to medication. "De novo" absence status of late onset is characterized by toxic or metabolic precipitating factors in middle-aged or elderly subjects with no previous history of epilepsy. Patients often have a history of psychiatric illness with multiple psychotropic drug intake. The electroclinical characteristics and the immediate prognosis are variable. These episodes of AS generally represent acute symptomatic seizures and may not recur if the triggering factors can be controlled or corrected. Long-term antiepileptic drugs may thus not be needed. Absence status with focal characteristics occur in subjects with a pre-existing or newly developing partial epilepsy, most often of extra-temporal origin. The EEG shows bilateral but often asymmetric ictal discharges. The immediate prognosis is variable. Some of these cases are difficult to distinguish from complex partial status epilepticus of frontal lobe origin.

Acute Disease↗
PubMed1999

[High-dose ifosfamide in patients with stage IV non-small cell lung cancer: phase II trial from the Groupe français de pneumo-cancérologie (GFPC)].

PURPOSE: To assess the toxicity and efficacy of high dose ifosfamide in stage IV NSCLC. METHODS: In a previous trial, we have determined maximum tolerated dose for 3-days ifosfamide treatment by 3-weeks schedule as 9 g/m2 according to hematologic tolerance. We therefore set up a phase II to study the toxicity and efficacy of this schedule in chemotherapy naive metastatic NSCLC. Ifosfamide (+ mesna 1 g/m2) was administered by a two hour infusion (3 g/m2) for three days every three weeks. Patients received three mesna bolus infusions (1 g/m2) at 4, 8 and 12 hours after the end of ifosfamide infusion. Antitumoral efficacy was performed after 2 cycles and treatment could be pursued for responding patients until disease progression. From september 1995 to January 1997, 31 patients have been included in this study. Median age was 60.7 years +/- 1.33 (41-70) for 27 males and 4 females. Patients (pts) presented metastases in lung for 10 pts, bone for 10 pts, liver for 6 pts, adrenal for 4 pts and multiorgan metastatic localisation for 1 patient. Seven patients were unassessable: 1 lost for follow-up, 1 sudden death, 5 treatment interruptions before evaluation time and 3 toxic deaths (9.6%). TOXICITY: neutropenia grade 4 (10 pts and 1 death), cardiotoxicity grade 4 (1 pt) and 2 deaths following neurotoxicity grade 4. We achieve 4 partial responses (13%, 95CI: 3.6-29.8), 10 progressive diseases (32.3%, 95CI: 16.7-51.4) and 10 stabilizations (32.3%, 95CI: 16.7-51.4). Median response duration was 91 days +/- 55 d. Median survival was 9.3 months, e.g. 280 days (8-863). Overall survival at one year is 48%. CONCLUSION: This modality of high dose ifosfamide is as effective as standard monotherapy schedules in stage IV NSCLC. Unexpected toxicities particularly hematological ones could be due to a short duration of fractionated treatment. Results in term of survival leads us to further evaluate ifosfamide monotherapy treatment on a 5-day schedule basis.

Adult↗
PubMed1998

Acetaldehyde inhibits NF-kappaB activation through IkappaBalpha preservation in rat Kupffer cells.

BACKGROUND AND AIMS: Treatment with acetaldehyde dehydrogenase inhibitors leads to increased liver acetaldehyde levels and prevents hepatic inflammation and necrosis in ethanol-fed rats. This is accompanied by IkappaBa preservation and decreased activation of nuclear factor (NF)-kappaB. The present in vitro study was aimed to clarify whether acetaldehyde has an effect on degradation of IkappaBalpha and activation of NF-kappaB in LPS-stimulated rat Kupffer cells. METHODS: Kupffer cells were isolated from male Sprague-Dawley rats and preincubated with various concentrations of acetaldehyde (25-100 microM). Thereafter the cells were stimulated with LPS, and cytosolic and nuclear fractions were prepared. IkappaBalpha and p65 proteins and activation of NF-kappaB were evaluated. RESULTS: In LPS-stimulated rat Kupffer cells, acetaldehyde diminished proteolytic degradation of IkappaBalpha, inhibited nuclear translocation of cytosolic p65 protein, and, accordingly, markedly decreased NF-kappaB activation. CONCLUSIONS: Acetaldehyde is clearly involved in the stabilization of IkappaBalpha protein and suppression of NF-kappaB activation in rat Kupffer cells. Acetaldehyde may form an adduct with IkappaBalpha, thus making the protein less susceptible to degradation.

Acetaldehyde↗
PubMed1998

Divided attention in major depression.

Depressive illness has been reported to interfere with effortful processing, which requires conscious attention. The aim of this study was to evaluate divided attention in depressed patients, as a function of the degree of difficulty of the task performed. Tasks designed to measure unimodal and bimodal reaction times were presented to 10 patients with major depression and 10 normal control subjects. Performance was evaluated both before treatment when the patients were depressed and after treatment when they had recovered. Unlike the unimodal trials, the bimodal reaction time tasks were designed to evaluate decision-making under conditions in which attention was divided between two perceptual channels. Reaction times were measured under two different conditions in order to assess the extent of the response delay induced by divided attention, modality shifting, and decision processing. During simple response tasks, the depressed patients displayed significantly greater lengthening of reaction times when their attention was divided between two perceptual channels. This cross-modal delay effect occurred both for stimuli of the same modality and when shifting between modalities. The cross-modal delay effect was evident only for the choice tests in both the depressed and the recovered patients, but only the recovered patients were as accurate as the control subjects. These results suggest that the need for decision processing in depressed patients results in a failure to allocate the mental resources required to complete interchannel shifting, when attention is divided between two perceptual channels. These data are consistent with the hypothesis that attentional regulation is impaired in major depression.

Adult↗
PubMed1998

Isolation of developmentally regulated genes by differential display screening of cDNA libraries.

mRNA differential display RT-PCR has been extensively used for the isolation of genes differentially expressed between RNA populations. We have assessed its utility for the identification of developmentally regulated genes in plasmid cDNA libraries derived from individual tissues dissected from early mouse embryos. Using plasmid Southern blot hybridisation as a secondary screen, we are able to identify such genes and show by whole-mount in situ hybridisation that their expression pattern is that expected from the differential display profile.

Animals↗
PubMed1998

Synthesis of 9-deoxo-4''-deoxy-6,9-epoxyerythromycin derivatives: novel and acid-stable motilides.

In our quest toward the discovery of highly potent and acid-stable motilides, novel 4"-deoxy derivatives of 9-deoxo-6, 9-epoxyerythromycin were designed, synthesized, and evaluated for their gastrointestinal prokinetic activities. These compounds, in their 9R configuration, were more potent than their 6,9-enol ether homologues in inducing well-coordinated smooth muscle contractions in an in vitro rabbit duodenal assay: e.g., (9R), (8S)-9-deoxo-4"-deoxy-3'-N-desmethyl-3'-N-ethyl-6, 9-epoxyerythromycin A (10) and (9R), (8S)-9-deoxo-4"-deoxy-3'-N-desmethyl-3'-N-ethanol-6, 9-epoxyerythromycin A (15) had a pED50 of 8.54 and 8.11 compared to a pED50 of 7.22 for compound 2 (ABT-229). Reduction of the 6,9-enol ether, which was aimed at improving the acid stability, afforded the most stable motilides to date with t1/2 of 5.5 h for 10 and 15. Compounds 10 and 15 bind specifically to rabbit antral smooth muscle motilin receptors with pIC50 values of 8.52 and 8.70.

Animals↗
PubMed1998

Role of ions and ion channels in the regulation of Atlantic croaker sperm motility.

The effects of the osmolarity and ionic composition of the external media and ion-channel blockers on the induction of sperm motility in the marine teleost, Atlantic croaker (Micropogonias undulatus) were investigated. An in vitro sperm motility assay was developed to determine treatment effects on the percentage of motile sperm, sperm speed, and turning rate, using a computer-aided motion-analysis system. Maximum activation of sperm motility occurred in saline with an osmolarity of 680 mOs/kg. Potassium caused a decrease in the percentage of motile sperm, but only at high nonphysiological concentrations in the presence of high amounts of calcium. Calcium caused an increase in sperm velocity and turning rate. Percent motility was inhibited by the potassium-channel blockers, 4-aminopyridine and veratrine, the calcium-channel blockers, verapamil, diltiazem, and nifedipine; the sodium-channel blocker, amiloride, and the chloride-channel blocker, ethacrynic acid. In addition, the calcium-channel blockers caused a decrease in sperm velocity and turning rate. These results provide evidence for the role of potassium, calcium, and possibly sodium, and chloride ions in Atlantic croaker sperm motility. In addition, this study demonstrates that membrane-bound ion channels are involved in the motility of sperm from a marine teleost.

Animals↗
PubMed1998

Early views of the martian surface from the Mars Orbiter Camera of Mars Global Surveyor.

High-resolution images of the martian surface at scales of a few meters show ubiquitous erosional and depositional eolian landforms. Dunes, sandsheets, and drifts are prevalent and exhibit a range of morphology, composition (inferred from albedo), and age (as seen in occurrences of different dune orientations at the same location). Steep walls of topographic depressions such as canyons, valleys, and impact craters show the martian crust to be stratified at scales of a few tens of meters. The south polar layered terrain and superposed permanent ice cap display diverse surface textures that may reflect the complex interplay of volatile and non-volatile components. Low resolution regional views of the planet provide synoptic observations of polar cap retreat, condensate clouds, and the lifecycle of local and regional dust storms.

Carbon Dioxide↗
PubMed1998

Carbamazepine in the treatment of neuroleptic malignant syndrome.

BACKGROUND: Neuroleptic malignant syndrome (NMS) is a potentially lethal adverse effect to neuroleptic drugs. METHODS: We report on 2 cases where NMS dramatically improved with carbamazepine. Incidental removal and reapplication of carbamazepine attests to its effectiveness for this condition. RESULTS: A 34-year-old woman treated for a major depressive disorder experienced NMS with a phenothiazine. Her condition dramatically improved in 8 hours after she was administered carbamazepine. Since carbamazepine was discontinued, NMS recurred in 10 hours and remitted anew within less than 24 hours after reintroduction. A 31-year-old woman experiencing a schizoaffective disorder displayed NMS with aphenothiazine and a butyrophenone. NMS completely resolved within 8 hours after she was administered carbamazepine. NMS recurred within 12 hours after carbamazepine discontinuation. CONCLUSIONS: These data thus account for a cause-effect relationship between carbamazepine administration and NMS relief, and argue against the neuroleptic withdrawal to be responsible by itself for NMS relief.

Adult↗
PubMed1998

Evidence for a subsurface ocean on Europa.

Ground-based spectroscopy of Jupiter's moon Europa, combined with gravity data, suggests that the satellite has an icy crust roughly 150 km thick and a rocky interior. In addition, images obtained by the Voyager spacecraft revealed that Europa's surface is crossed by numerous intersecting ridges and dark bands (called lineae) and is sparsely cratered, indicating that the terrain is probably significantly younger than that of Ganymede and Callisto. It has been suggested that Europa's thin outer ice shell might be separated from the moon's silicate interior by a liquid water layer, delayed or prevented from freezing by tidal heating; in this model, the lineae could be explained by repetitive tidal deformation of the outer ice shell. However, observational confirmation of a subsurface ocean was largely frustrated by the low resolution (>2 km per pixel) of the Voyager images. Here we present high-resolution (54 m per pixel) Galileo spacecraft images of Europa, in which we find evidence for mobile 'icebergs'. The detailed morphology of the terrain strongly supports the presence of liquid water at shallow depths below the surface, either today or at some time in the past. Moreover, lower-resolution observations of much larger regions suggest that the phenomena reported here are widespread.

Extraterrestrial Environment↗
PubMed1998

Episodic plate separation and fracture infill on the surface of Europa. Galileo Imaging Team.

Images obtained by the Voyager spacecraft revealed dark, wedge-shaped bands on Europa that were interpreted as evidence that surface plates, 50-100 km across, moved and rotated relative to each other. This implied that they may be mechanically decoupled from the interior by a layer of warm ice or liquid water. Here we report similar features seen in higher resolution images (420 metres per pixel) obtained by the Galileo spacecraft that reveal new details of wedge-band formation. In particular, the interior of one dark band shows bilateral symmetry of parallel lineaments and pit complexes which indicates that plate separation occurred in discrete episodes from a central axis. The images also show that this style of tectonic activity involved plates < 10 km across. Although this tectonic style superficially resembles aspects of similar activity on Earth, such as sea-floor spreading and the formation of ice leads in polar seas, there are significant differences in the underlying physical mechanisms: the wedge-shaped bands on Europa most probably formed when lower material (ice or water) rose to fill the fractures that widened in response to regional surface stresses.

Geological Phenomena↗
PubMed1998

Aminobacterium colombiensegen. nov. sp. nov., an amino acid-degrading anaerobe isolated from anaerobic sludge.

A new gram-negative, non-sporulating, mesophilic, amino acid fermenting bacterium, designated strain ALA-1(T) (T = type strain), was isolated from an anaerobic lagoon of a dairy wastewater treatment plant. The strain is curved (3-4 microm x 0.2-0.3 microm) and occurs singly or in pairs. Optimum growth occurs at 37 degrees C and pH 7.3. The G+C content of the DNA is 46 mol %. The strain requires yeast extract for growth, grows poorly on casamino acids, peptones, cysteine, and alpha-ketoglutarate, but readily grows on serine, threonine, glycine and pyruvate. When cocultured with the hydrogenotrophic methanogen Methanobacterium formicicum, strain ALA-1(T) oxidized alanine, glutamate, leucine, isoleucine, valine, aspartate, and methionine. Phylogenetic analysis revealed that it forms a distinct and independent line of descent in the vicinity of Dethiosulfovibrio peptidovorans, Dictyoglomus thermophilum, and Anaerobaculum thermoterrenum which are members of the low G+C containing gram-positive bacteria. The phylogenetic results concur with the phenotypic and genomic data which reveal that it is a novel strain. Based on these findings, we designate strain ALA-1(T) as Aminobacterium colombiense (DSM 12261) gen. nov., sp. nov.

Journal Article↗
PubMed1998

Eubacterium aggreganssp. nov., a new homoacetogenic bacterium from olive mill wastewater treatment digestor.

A strictly anaerobic, homoacetogenic, gram-positive, non spore-forming bacterium, designated strain SR12(T) (T = type strain), was isolated from an anaerobic methanogenic digestor fed with olive mill wastewater. Yeast extract was required for growth but could also be used as sole carbon and energy source. Strain SR12(T) utilized a few carbohydrates (glucose, fructose and sucrose), organic compounds (lactate, crotonate, formate and betaine), alcohols (methanol), the methoxyl group of some methoxylated aromatic compounds, and H2 + CO2. The end-products of carbohydrate fermentation were acetate, formate, butyrate, H2 and CO2. End-products from lactate and methoxylated aromatic compounds were acetate and butyrate. Strain SR12(T) was non-motile, formed aggregates, had a G+C content of 55 mol % and grew optimally at 35 degrees C and pH 7.2 on a medium containing glucose. Phylogenetically, strain SR12(T) was related to Eubacterium barkeri, E. callanderi, and E. limosum with E. barkeri as the closest relative (similarity of 98%) with which it bears little phenotypic similarity or DNA homology (60%). On the basis of its phenotypic, genotypic, and phylogenetic characteristics, we propose to designate strain SR12(T) as Eubacterium aggregans sp. nov. The type strain is SR12(T) (= DSM 12183).

Journal Article↗