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Biomedical subjects

P Hubert

Publications and source records attributed to P Hubert.

At least 181 records · Page 10Linked to original sources
PubMed1991

Rapid determination of 5-hydroxytryptamine in whole blood by liquid chromatography with fluorimetric detection.

A rapid and simple reversed-phase (using muBondapak C18 as the stationary phase) liquid chromatographic method with fluorimetric detection is described for the quantitation of 5-hydroxytryptamine in whole blood. The rapidity and simplicity of the method are explained by the absence of a pretreatment. 5-Fluoro-dl-tryptophan was used as internal standard. The mobile phase was 0.01 M phosphate buffer (pH 4.5) with 0.0025 M 1-heptanesulfonic acid and 20% methanol. The detection wavelength were 302 nm for excitation and 340 nm for emission. Analysis time was 10 min with retention times for 5-hydroxytryptamine of 9 min and for 5-fluoro-dl-tryptophan of 7 min. This method is proposed for biological exploration of psychiatric disorders involving 5-hydroxytryptamine and would be useful for tryptophan.

Chromatography, Liquid↗
PubMed1991

[Pierre Robin syndrome].

During the last few years, our knowledge of Pierre Robin syndrome has benefited from advances in embryonic neurobiology. It has been shown that the syndrome is related to an anomalous development of the foetal brainstem. A multidisciplinary study makes it possible to value prospectively the various anomalies with which it may be associated and to decide on a coherent treatment. This type of management should reduce the mortality and prevent the sequelae of Pierre Robin syndrome.

Humans↗
PubMed1991

Meningioma of the third ventricle. Computed tomography and magnetic resonance imaging.

Meningiomas of the third ventricle are rare intracranial neoplasms. We reported such a case in a 42 years old man without clinical evidence of increased intracranial pressure. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated the tumour sitting in the superior and anterior part of the third ventricle, bulging into the lateral ventricles. CT was more effective than MRI in the demonstration of calcifications whereas MRI proved to be superior in delineation of the tumour and its relation with surrounding structures.

Adult↗
PubMed1991

Automatic determination of diltiazem and desacetyldiltiazem in human plasma using liquid-solid extraction on disposable cartridges coupled to HPLC--Part I: Optimization of the HPLC system and method validation.

A sensitive and automated method for the analysis of diltiazem and desacetyldiltiazem in plasma has been developed using liquid-solid extraction (LSE) on disposable extraction cartridges (DECs) in combination with HPLC. After isolation from plasma, the analytes are separated on a highly deactivated octyl silica column with a mobile phase of methanol-0.05 M phosphate buffer (pH 7.4) (62:38, v/v). The analytes are monitored photometrically at 238 nm. The complete preparation of the plasma sample as well as the injection of the final extract on to the analytical column are performed automatically by means of a sample processor equipped with a robotic arm to which is attached a needle dispensing the different liquids. The internal standard solution is first added to the plasma sample. The DEC is then conditioned successively with methanol and phosphate buffer (pH 7.4). A 1.0-ml volume of sample containing the internal standard solution is applied on an extraction cartridge filled with cyanopropyl silica (50 mg). After the DEC has been washed with the same buffer, the analytes are eluted with 0.16 ml of methanol. A 0.14-ml volume of buffer is then passed through the DEC and 0.25 ml of the final extract is injected onto the HPLC column. The absolute recoveries of the drugs are about 90% and the limit of detection for diltiazem is 0.8 ng ml-1. Relative standard deviations of 2.6% (within-day) and 3.7% (between-day) have been obtained for this compound at a plasma concentration of 50 ng ml-1.

Automation↗
PubMed1991

Automatic determination of diltiazem and desacetyldiltiazem in human plasma using liquid-solid extraction on disposable cartridges coupled to HPLC--Part II: Optimization of liquid-solid extraction.

An automatic liquid-solid extraction (LSE) procedure to be coupled to HPLC for the determination of diltiazem and desacetyldiltiazem in plasma has been developed. The LSE operations are performed on disposable extraction cartridges (DECs) by means of a sample processor equipped with a robotic arm holding a needle through which the different liquids are dispensed. The operating parameters of LSE have been optimized with respect to recovery, detectability and reproducibility by using, whenever possible, aqueous solutions of the analytes. Different kinds of DECs have been tested. For the compounds studied, DECs filled with 50 mg of cyanopropyl silica have been selected. The influence of the pH of the buffer used in the washing step has been studied, leading finally to the selection of the same phosphate buffer (pH 7.4) as in the HPLC mobile phase. The minimum volume of methanol which still gives a nearly complete elution of the analytes from the extraction cartridges has been determined. Under these conditions, a high sensitivity can be obtained without an evaporation step. Moreover, the volume of buffer to be added to the methanolic eluate before injection into the HPLC system has been optimized in such a way that a focusing effect is obtained at the top of the analytical column while the dilution of the extract is minimized.

Automation↗
PubMed1991

[Cerebral anoxia in near-drowning of children. The prognostic value of EEG].

The retrospective electroclinical evaluation of anoxia by near-drowning in 23 children observed between 1985 and 1989 revealed 2 groups, each with a distinct evolution: the first group, with good prognosis of 17 children, which recovered consciousness without neurological complications between 2 d and 1 wk after the accident. The second group of 6 children with a poor outcome--either i), death; or ii), state of permanent injury; or iii), a high level of clinical deficits. The gravity of the early clinical state, the estimated duration of cardiorespiratory arrest, the severity of the hypothermia, the seizures and the paroxysmic activity, do not determine the severity of near-drowning encephalopathy. The EEG patterns described in correlation with the group and the clinical outcome permitted determination of prognostic criteria. A good prognostic consisted of the following: moderate background activity, sleep patterns, response to auditory and painful stimulations, and numerous beta rhythms. A bad outcome was defined by: high voltage, rhythmic delta waves; biphasic sharp waves; monotonous EEG, "burst-suppression" pattern, absence of beta rhythms. The importance of EEG recordings is emphasized performed as early as possible and until 3 or 7 d after the near-drowning. Any modification in the EEG, with attenuation or disappearance of fast frequencies and painful reactivity, appearance or enhancement of slow and biphasic sharp waves, are ominous signs and may be accompanied by the appearance of cerebral oedema and decerebration.

Child↗
PubMed1991

Lipid-induced insulin resistance in cultured hepatoma cells is associated with a decreased insulin receptor tyrosine kinase activity.

We have shown previously that experimental modifications of the cellular lipid composition of an insulin-sensitive rat hepatoma cell line (Zajdela Hepatoma Culture, ZHC) affect both binding and biological actions of insulin. Discrepancies between insulin binding and actions implied a postbinding defect, responsible for the observed insulin resistance in lipid-treated cells. To elucidate the mechanism for this defect, we have studied insulin binding and insulin receptor kinase activity in partially purified receptor preparations from ZHC cells grown either in normal medium or in medium supplemented with linoleic acid or 25-hydroxycholesterol. Insulin binding to the lectin-purified insulin receptor showed only a small alteration in receptor affinity for the preparations from lipid-treated cells. Insulin-stimulated autophosphorylation of the beta-subunit of the insulin receptor, as well as insulin-induced phosphorylation of the artificial substrate poly(Glu,Tyr)4:1, was significantly decreased in the preparations from lipid-modified cells. Although differences in basal levels were observed, the magnitude of the insulin-stimulated kinase activity was significantly decreased in receptor preparations from lipid-treated cells. These findings indicate that experimental modification of the lipids of cultured hepatoma cells can produce in insulin receptor kinase activity changes that are proportional to the reduced insulin action observed in these cells.

Adenosine Triphosphate↗
PubMed1991

[Hepatic and renal transplantation in the treatment of type I hyperoxaluria].

Hyperoxaluria type I (HPI) is a metabolic disorder secondary to liver alanine glyoxylate aminotransferase deficiency. Renal failure occurs due to the excessive production and precipitation of oxalate in the kidney. Combined liver-renal transplantation is the correct treatment for this condition when end-stage renal failure occurs as with renal transplantation alone the risk of recurrence of the same pathology in the transplanted kidney would be high. We report the case of a 4 year-old child with HPI suffering from terminal renal failure in whom a hepato-renal transplantation was performed: six months later, creatinine clearance was 62 ml/min/1.73 m2 and liver function tests were normal.

Actuarial Analysis↗
PubMed1991

[Spinal lipoma associated with a neuromuscular hamartoma. Report of one case].

A 6 year-old boy with urinary incontinence, sensory loss and spastic weakness in lower limbs underwent surgical repair for low-lying spinal cord ending in an intradural lipoma. Within the lipoma, bundles and fascicles of striated muscles fibers were intimately associated with nerve fibers. This extremely rare histological appearance has been reported as benign "triton tumor". Our case allows a discussion of its histogenesis.

Child↗
PubMed1991

[Disseminated mucormycosis in pediatrics].

The case of a 14 month-old infant presenting with hereditary lymphohistiocytosis is reported. After several days of post-chemotherapy aplasia a peritoneal, cutaneous (blackish necrosis), then pleuropulmonary involvement occurred. Fiberendoscopy showed an esophageal necrosis responsible for a pleural fistula. The child died after a few weeks, despite antifungal treatment. Post mortem examination found disseminated abscesses related to mucormycosis. The 41 pediatric cases in the world-wide literature are recorded.

Female↗
PubMed1991

[Isolated exertion headache and Chiari's malformation].

A 47 year-old woman had been suffering from exertional headache for 2 1/2 years. Neurological examination was normal. X-rays of the skull and cranio-cervical junction and CT were normal. MRI sagittal sections disclosed a Chiari type I malformation. The headache disappeared after occipital craniectomy and atlas laminectomy.

Arnold-Chiari Malformation↗
PubMed1990

Increased immunogenicity of human renal carcinoma cells following treatment with cholesterol derivatives.

Tumor cells isolated from human renal cell carcinoma biopsies were treated with cholesteryl hemisuccinate or 25-hydroxycholesterol and the subsequent changes in their membrane fluidity and capacity to induce skin reactivity in the homologous patient were investigated. Both cholesterol derivatives were found equally efficient in decreasing membrane fluidity when measured by fluorescence polarization of diphenylhexatriene. Using trimethylammonium-diphenylhexatriene, a specific cell surface probe, 25-hydroxycholesterol, appeared much more efficient than cholesteryl hemisuccinate in inducing a membrane rigidification in the carcinoma cells. Cells treated with cholesteryl hemisuccinate induced a strong positive skin reaction compatible with delayed-type hypersensitivity in 54% of the patients, whereas 25-hydroxycholesterol-treated cells were less potent (36% positive skin reactions). Thus, manipulation of the physicochemical state of the membrane of human renal carcinoma cells could increase their immunogenicity in the autologous patient, although this seemed not to be related only to membrane rigidification.

Aged↗
PubMed1990

[Stimulation of antigenicity of renal adenocarcinoma cells].

It was hypothesized that membrane rigidification of tumor cells could enhance the expression of tumor associated antigens (6) For this purpose, we treated in vitro hypernephroma cell with cholesterol hemisuccinate (CHS) or 25-hydroxysterol (250HC) and we evaluated their immunogenicity by skin-tests in 26 patients after radical nephrectomy. The skin-tests were positive in 50% cases with CHS treated cells, and in 35% with 250HC treated cells. The immune responses were characterized as delayed hypersensitivity. However determinations of all membrane fluidity suggested that membrane rigidification was not the unique factor involved. These results could therefore be of clinical interest in the treatment of renal carcinoma by active immunotherapy.

Adenocarcinoma↗
PubMed1990

[The subperiosteal subtemporal approach in the surgical treatment of craniostenosis. Apropos of 9 cases].

The authors describe the approach consisting of direct subperiosteal, subtemporal cleavage based on existing anatomical continuity between the subtemporal plane and the cranial periosteum in young children. This allows for downward cleavage up to the level of the malar processes, for dissecting both orbits as well as the external columns. Frontoorbital remodeling which is needed for management of craniostenosis may be readily carried out with the improved field of vision. It will suffice, then, to depress the scalp and to suture the skin to obtain perfect repositioning of the temporal muscle, remaining one piece with the cutaneous plane and maintained steady thanks to the salvaged continuity of the periosteum with the subtemporal plane. Utilization of this approach avoids having to cleave the temporal muscle superficially, to section and then reinsert it to the bony frontoorbital fascia after remodeling, thereby constituting a simplified technique of craniostenosis management. Experience gained in craniostenotic children treated via this direct subperiosteal subtemporal approach opens the way for possible applications in adult traumatology patients, as well as for the constitution of unilateral pterion flaps without jeopardizing the frontal ramus of the facial nerve.

Cranial Sutures↗
PubMed1989

A fully automated high-performance liquid chromatographic method for the determination of indomethacin in plasma.

A fully automated method is described, which enables the determination of indomethacin in plasma by reversed-phase HPLC following on-line sample enrichment and clean-up on a short pre-column. The plasma sample is introduced directly into the column switching system. The pre-column, filled with a pellicular bonded phase, is first washed with phosphate buffer, pH 7.4. The compounds retained on the pre-column are then eluted in the fore-flush mode and separated on an octadecylsilica column with a methanolic phosphate buffer (pH 7.4) mobile phase. Indomethacin is determined spectrophotometrically at 254 or 260 nm. The effect of changes in the pH and flow rate of the washing eluent are studied. Under the conditions selected, memory effects can be avoided, the absolute recovery of the drug is 70% and the limit of detection 10 ng ml-1 for a 100 microliter injection of plasma. At a concentration of 100 ng ml-1, the relative standard deviations (RSD) are 1.7% (within-day) and 3.5% (between-day), respectively.

Autoanalysis↗
PubMed1989

[Severe respiratory syncytial virus infections. Study of 87 infants hospitalized in an epidemic].

During a winter epidemic, 87 infants were admitted to Necker-Enfants-Malades hospital with a severe respiratory syncitial virus (RSV) infection. These infants fell into two groups: 37 infants without any medical history and 50 showing an underlying pathology (immune deficiencies, heart disease, CNS disorders, digestive malformations, allergic manifestations). Of the 37 infants with no medical history, most were below the age of 6 months and the RSV infection was manifested clinically by bronchiolitis or bronchitis. Most of the infants in the other group were more than 6 months of age and presented mostly with pneumonia or bronchiolitis. A respiratory distress syndrome was observed in 17 of the 87 infants, and virtually all of them were younger than 6 months. No significant difference was observed between the two groups with regards to the incidence of respiratory distress. Pulmonary infections complicating the course of the illness, most often due to commensal flora bacteria of the upper respiratory tract, were observed in 19 infants but with no greater frequency in the group at risk. Direct detection of viral antigens in nasopharyngal secretions not only enabled rapid diagnosis in all the infants but also allowed antiviral therapy to be started rapidly. Antiviral treatment by ribavirine, administered over a period of 5 days in 20 mg/ml doses by aerosol was instituted in 10 patients whose course might have become serious. In 8 of these patients, disappearance of the virus from secretions and recovery occurred. Two patients in the group at risk died despite treatment, with one case being considered a true therapeutical failure since the virus was still present in nasopharyngeal secretions.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Hospitalized↗
PubMed1989

[Intracerebellar schwannoma. Apropos of a case. Review of the literature].

Intracranial schwannoma represents 8% of all primary brain tumors. It usually develops from the Schwann cells of a cranial nerve. Hemispheric intraparenchymal localisations are quite rare; 15 cases have been reported (3, 5, 12, 10, 14, 15, 18, 19, 23, 26, 28, 29) including one intraventricular localization (8). Intracerebellar localization is even by more exceptional. In 1977, one case was reported by Komminoth (16). Since then only one other case has been published in 1987 by Sarkar (25). In this paper, we report a third case.

Cerebellar Neoplasms↗