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Biomedical subjects

P Noël

Publications and source records attributed to P Noël.

At least 19 recordsLinked to original sources
PubMed2005

Migration of adjustable gastric banding from a cohort study of 4236 patients.

BACKGROUND: Experience was gained management of intra-gastric migration of adjustable gastric banding. METHODS: From July 1996 to January 2003, 4236 patients who underwent laparoscopic adjustable gastric banding were proposed for routine follow-up. Gastrograms were performed in case of band adjustment. Radiological controls and endoscopy were performed according to symptoms. RESULTS: A total of 45 cases of band migration (1.6%) were diagnosed during follow-up. All but one of the migrated bands were removed laparoscopically either by a dissection outside the stomach or through a short gastrotomy. Mortality was 0% and morbidity 8% (n = 4). CONCLUSION: The risk of an intragastric band migration remains low in the literature but could grow on account of the longer follow-up of patients. The retrieval of the band is the gold standard and must be planned promptly or delayed according to symptoms.

Adolescent↗
PubMed2000

Head stability during whole body movements in spastic diplegia.

Head angular stability is essential for postural control in whole body movement. Using the opto-electronic ELITE system, we have studied head orientation during the movements of squatting from the standing position and straightening-up from the squatting position in 12 children with spastic diplegia and 12 age-matched controls. Although no instruction was given regarding the head, diplegic children consistently performed excessive neck flexion in the squatting movement and excessive hyperextension in the straightening-up movement, whereas normal children maintained the initial orientation throughout both movements. We discuss pathophysiological implications.

Cerebral Palsy↗
PubMed2000

Multistep production of bioengineered skin substitutes: sequential modulation of culture conditions.

Many studies are being conducted to define the role of growth factors in cutaneous physiology in order to add cytokines in a timely fashion for optimal tissue engineering of skin. This study is aimed at developing a multistep approach for the production of bioengineered skin substitutes, taking into account the effects of various growth factors according to the culture time. The use of a serum-supplemented medium throughout the whole culture period of skin substitutes was compared to the sequential use of specific additives at defined culture steps. Histological analysis revealed that serum was necessary for keratinocyte proliferation and migration on dermal substitutes during the first 2 d after their seeding. However, the serum-free medium presented some advantages when supplemented with different additives at specific culture steps. Interestingly, ascorbic acid added to the dermal substitutes before and after keratinocyte seeding maintained their cuboidal morphology in the basal epidermal layer. In the absence of serum, collagen matrix degradation slowed down, and a better multilayered epidermal organization was obtained, notably with retinoic acid. Stratum corneum formation was also enhanced by fatty acids. Thus, sequential addition of exogenous factors to the medium used to produce skin substitutes can improve their structural features and functional properties in vitro.

Animals↗
PubMed1999

Spironolactone-related inhibitors of type II 17beta-hydroxysteroid dehydrogenase: chemical synthesis, receptor binding affinities, and proliferative/antiproliferative activities.

The family of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) catalyzes the formation and inactivation of testosterone (T), dihydrotestosterone (DHT), and estradiol (E2), thus playing a crucial role in the regulation of active steroid hormones in target tissues. Among the five known 17beta-HSD enzymes, type II catalyzes the oxidation of E2 into estrone (E1), T into androstenedione, DHT into androstanedione, and 20alpha-dihydroprogesterone into progesterone. Specific inhibitors are thus an interesting means to study the regulation and to probe the structure of type II 17beta-HSD. In this context, we have efficiently synthesized a series of 7alpha-thioalkyl and 7alpha-thioaryl derivatives of spironolactone that inhibit type II 17beta-HSD. These new C19-steroidal inhibitors possess two important pharmacophores, namely 17-spiro-gamma-lactone and a bulky side-chain at the 7alpha-position. It was found that a para-substituted benzylthio group at the 7alpha-position enhances the inhibitory potency of spironolactone derivatives on type II 17beta-HSD. In fact, the compound with a para-hydroxy-benzylthio group showed an IC50 value of 0.5 microM against type II 17beta-HSD, whereas the compound with a para-[2-(1-piperidinyl)-ethoxy]-benzylthio group inhibited this enzyme with an IC50 value of 0.7 microM. The latter inhibitor is more selective than the former because it did not show any inhibitory potency against P450 aromatase as well as any affinity towards four steroid receptors (AR, PR, GR, ER). As a result, this inhibitor did not show any proliferative effect on androgen-sensitive Shionogi cells and estrogen-sensitive ZR-75-1 cells. These findings contribute to a better knowledge of the structure of type II 17beta-HSD and offer an interesting tool to study the regulation of this enzyme in several biological systems.

17-Hydroxysteroid Dehydrogenases↗
PubMed1999

Adaptive motor strategy for squatting in spastic diplegia.

Motor strategies, defined by kinetic, kinematic and/or muscle activation patterns, reflect neural planning of movement, which takes into account central as well as peripheral constraints. Major alteration is expected in cerebral palsy, a condition characterized by abnormal posture and movement secondary to early lesion of the brain. The objective of this study was to characterize the motor strategies involved in disruption of posture in cerebral palsy of the spastic diplegia type and compare them with normal controls. The optoelectronic ELITE system was used to record and analyse the movement of squatting from the standing position with the arms extended forward in 11 children with spastic diplegia aged between 3 and 12 years and 11 age-matched normal controls. Normal children maintained gaze and arm horizontality and trunk verticality throughout the movement. The knee followed an oblique trajectory. Its angular velocity profile showed a short, single-peaked, ascending phase. The onset of movement was preceded by deactivation of the semimembranous muscle. In diplegic children, gaze and arm horizontality and trunk verticality were lost. The ankle was rigidified, resulting in spatial fixation of the knee. The ascending phase of the knee velocity profile was prolonged and multi-peaked. There was widespread muscle co-contraction from the outset of movement. No anticipatory deactivation was evidenced, but anticipatory bursts appeared in the soleus. Patients with cerebral palsy have to organize a limited motor repertoire from a restricted neural potential. Consequent motor strategies presently demonstrated in spastic diplegia are distinct and appear as an original alternative to those of normal subjects.

Biomechanical Phenomena↗
PubMed1998

[Corticosteroid-induced epidural lipomatosis. Efficacy of medical treatment].

We describe a further case of cauda equina compression secondary to steroid-induced epidural lipomatosis in a patient treated for IBD. The diagnosis was rapidly confirmed by MRI allowing conservative management by corticosteroid withdrawal as well as use of hygiene and dietary measures. Therapeutic efficacy was noted on a clinical basis and confirmed by repeated follow-up MRI exams which showed regression of fat accumulation. Symptomatic epidural lipomatosis is probably underestimated because physicians concerned by steroid treatment are not fully informed about this potentially severe and usually iatrogenic disease. Also, proper medical attention to the first neurological symptom in these patients might help limit therapeutic management to a medical measurer, before requiring surgical decompressive surgery.

Adult↗
PubMed1997

Magnetic transcranial stimulation: dissociation of excitatory and inhibitory mechanisms in acute strokes.

Magnetic transcranial stimulation was applied to 12 normal subjects and 30 patients (24 acute and 6 chronic) with hemiparesis contralateral to an ischaemic stroke. In the 24 acute patients, the recordings were made at the 7th day on the contralateral first dorsal interosseous (FDI) muscle. We studied the amplitudes of the motor evoked potential (MEP) responses and the post-MEP silent period durations (SPD) at different levels of stimulation intensity (SI) and voluntary isometric contraction (VIC). The evolution of these parameters was matched to the clinical status of the 24 acute patients evaluated 7, 30 and 90 days after the stroke (D7, D30 and D90). Our results may be summarised as follows: (1) in all cases, the MEP-amplitudes increased with facilitation and SI; (2) in the normal subjects and in patients who did recover, the SPD augmented with stronger SI but was found to be independent on the strength of voluntary contraction; (3) in the acute patients with poor recovery, as well as in the chronic patients with spasticity, the SPD decreased with stronger VIC. It may be concluded that MEP-amplitudes and SPD patterns point out excitatory and inhibitory mechanisms which may be differently affected in cerebral injuries. The association between shortening of the SPD with increasing VIC of the target muscle and poor recovery of the stroke after 3 months could be a useful clinical test to predict eventual recovery early after a stroke.

Acute Disease↗
PubMed1997

Magnetic transcranial stimulation: clinical interest of the silent period in acute and chronic stages of stroke.

There is little information on the silent period during facilitation of the target muscle at the acute stage of stroke and the ultimate clinical status. We studied 69 subjects with transcranial magnetic stimulation: 20 matched controls and 49 hemiparetic patients investigated 7 and 90 days after the stroke (D7, D90). We measured the silent period duration (SPD) in the first dorsal interosseous muscle at 10 and 100% of maximal voluntary isometric contraction (VIC). The SPD index (the ratio of SPD at VIC 100% by SPD at VIC 10%) at D7 was matched with the clinical outcome at D90. Two patterns of responses could be determined at D7. In the normal subjects and in 27 out of 32 patients who eventually recovered satisfactory function at D90, the SPDs were stable during facilitation (SPD index 100%). On the contrary, in 10 out of the 17 patients with a poor functional outcome, the mean SPD decreased when VIC was increased (SPD index 80%); besides, their muscle tone was significantly increased at D90. Similar patterns were still present in the patients at D90: the mean SPD indexes were not significantly different from D7. We conclude that in the early stage of stroke, a low SPD index appears to be correlated with the eventual occurrence of spasticity.

Aged↗
PubMed1996

Origin of N18 and P14 far-fields of median nerve somatosensory evoked potentials studied in patients with a brain-stem lesion.

Somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded in 3 patients with a brain-stem or medullary lesion documented by clinical and CT or MRI evidence. The positive P14 and negative N18 scalp far-fields were preserved. The results suggest that P14 reflects the spike volley in caudal medial lemniscus, and that the N18 neural generators are located in the medulla, probably in the dorsal column nuclei and/or the accessory inferior olives.

Adult↗
PubMed1996

Magnetic transcranial stimulation in acute stroke: early excitation threshold and functional prognosis.

Magnetic transcranial stimulation was used in 90 subjects (60 acute ischaemic sylvian strokes and 30 healthy controls) in order to evaluate the clinical value of the excitation threshold (ET) in the estimation of functional prognosis. ET mean values recorded 7, 30 and 90 days after stroke (at D7, D30 and D90) in two distal muscles of the upper limbs of the patients were compared with results obtained in 30 healthy control subjects. The data from the patients who ultimately achieved a satisfactory functional recovery at D90 were compared with those from patients who had not recovered in that time. Our results suggest that ET evolution differs according to functional outcome: (1) ET mean values were increased in the stroke patients at D7, but ET was constantly lower at D30 and D90 in patients who recovered than in those who did not. (2) ET temporal evolution showed a gradual decrease of the mean values from D7 to D90 in both stroke groups. This ET decrease was more marked in the patients who recovered from D30 to D90, but with only minor change after D30. (3) The localisation of the lesion had no significant effect on ET mean values at D7, D30 or D90. We conclude that the predictive value of ET estimation might be utilised at D30 in patients with ischaemic sylvian strokes.

Adult↗
PubMed1995

Magnetic transcranial stimulation in non-haemorrhagic sylvian strokes: interest of facilitation for early functional prognosis.

Magnetic transcranial stimulation was applied to 40 patients in the early stage of a non-haemorrhagic sylvian stroke. Results were evaluated with regards to the clinical outcomes at days 7, 30 and 90. The presence or absence of an early response had a critical prognostic significance. Response latency and amplitude parameters and the excitation threshold were of little value. Facilitation in patients unresponsive at rest was another determinant parameter since 9 out of 10 such cases ultimately recovered.

Adult↗
PubMed1994

A Sec62p-related component of the secretory protein translocon from Drosophila displays developmentally complex behavior.

The isolation and characterization of a Drosophila melanogaster gene (Dtrp1) that encodes a protein displaying the properties of both a structural and functional homolog of the yeast endoplasmic reticulum membrane-bound translocation protein Sec62p is reported. We show that Dtrp1 can not only rescue the lethality associated with a SEC62 gene knockout in yeast, but also complement the sec62-associated defective transport of a precursor polypeptide from the cytoplasm into the lumen of the endoplasmic reticulum. Expression of the Dtrp1 gene throughout Drosophila development is characterized by peaks in mid-embryo-genesis and mid-pupation, followed by a sustained period of mRNA accumulation in adults. The examination of male reproductive tissues showed a very high level of preferential expression of a 1.6 kb message, while a 2.2 kb message was confined almost exclusively to the non-reproductive tissues. Within the reproductive tract itself the 1.6 kb message was expressed in testes, ejaculatory duct and particularly strongly in the paragonial glands. Since these latter organs are specialized secretory tissues we suggest that the 1.6 kb message may encode a protein isoform that performs a unique, tissue-specific role in the protein translocation pathway. Such observations may indicate a hitherto unexpected diversity in components of the protein translocation pathway in respect to stage, tissue and, potentially, substrate specificity.

Amino Acid Sequence↗
PubMed1994

Neurophysiologic detection of a unilateral motor deficit occurring during the noncritical phase of scoliosis surgery.

STUDY DESIGN: A four-path neurophysiologic monitoring system was designed for spinal cord monitoring during spinal surgery. It was used mainly during scoliosis surgery. OBJECTIVE: To evaluate the efficacy of this technique. METHODS: Sensory and motor pathways were continuously monitored bilaterally from skin incision to awakening, with independent evaluation of the right and left pathways for each modality. RESULTS: This monitoring technique detected a transient unilateral motor deficit that occurred during the dissection phase of spinal surgery for scoliosis before any instrumentation or mobilization of the spine.

Adolescent↗
PubMed1994

Acute lymphocytic leukemia in adults: a retrospective study and analysis of current management options.

OBJECTIVE: To examine current therapeutic modalities for acute lymphocytic leukemia (ALL) in adults, analyze prognostic variables, and offer treatment recommendations. DESIGN: We reviewed our experience with 90 adult patients with ALL examined at the Mayo Clinic between 1982 and 1992 and used it as a background for discussion of prognostic factors and management options in adult patients with ALL. MATERIAL AND METHODS: The pretreatment characteristics of patients, types of induction chemotherapy, and postremission treatment, including bone marrow transplantation (BMT), were analyzed for prognostic significance for each of three outcomes: complete remission (CR) rate, duration of CR, and overall survival of patients. RESULTS: Of the 90 study patients, 80 had received induction chemotherapy. Overall long-term survival for treated patients was 25%. None of the 10 patients younger than 18 years of age underwent BMT, and their long-term survival was 80%. Of the other 70 patients, who were 18 years old or older, 42 (60%) had a CR with induction chemotherapy. Of these 42 patients, 31 did not undergo BMT, and their long-term survival was less than 13%. BMT was done in six patients during a first CR (with 100% survival), in four during a later CR (with 50% survival), and in six with disease (with 17% survival). The median age of patients who received chemotherapy was 50 years (range, 19 to 87) and that of patients who underwent BMT was 34 years (range, 18 to 46). Overall, age was the only significant prognostic factor. CONCLUSION: With our application of current chemotherapy, the outcome in adult patients (18 years old or older) with ALL was dismal. The results were considerably better in patients younger than 18 years of age or in those who underwent BMT as post-remission therapy. Comprehensive assessment of our experience and that in the literature, however, did not resolve issues about current management. Participation of patients in comparative trials is critical for determining the best therapy for ALL in adults.

Adolescent↗
PubMed1994

Incidence of leukemia in Olmsted County, Minnesota, 1975 through 1989.

OBJECTIVE: To determine the incidence of leukemia in Olmsted County, Minnesota, for a recent 15-year period and to compare the data with reported rates for the previous 40 years. DESIGN: We conducted a population study of leukemia diagnosed between 1975 and 1989 in residents of Olmsted County by review of medical records identified through diagnostic indexes, death certificates, autopsy files, and histologic preparations. MATERIAL AND METHODS: Diagnoses of leukemia were categorized into various subtypes, and age- and sex-specific incidence rates were calculated for leukemia as a whole and for each subtype. In addition, incidence rates were age- and sex-adjusted to the 1970 US white population for comparison with earlier published rates. Age and annual trends as well as sex differences were assessed with the generalized linear interactive model approach. RESULTS: During 1975 through 1989, the mean annual incidence rate for leukemia was 12.3 per 100,000 population in Olmsted County. When adjusted for age and sex, the rate per 100,000 was 13.6, in comparison with a similarly adjusted rate of 11.8 for the previous decade (1965 through 1974). The rates for chronic myelogenous leukemia and acute lymphocytic leukemia remained stable throughout the entire study period; however, rates for acute myelogenous leukemia and chronic lymphocytic leukemia increased, most prominently in patients 50 years of age or older. This increased rate occurred in both males and females, but the incidence rates for both subtypes began increasing earlier for males than for females. CONCLUSION: Although we cannot rule out an actual increase in incidence rates for these types of leukemia in the elderly population, we believe that the increase in persons older than 50 years of age reflects social change in improved health care and its better utilization by elderly persons, as well as the ability to diagnose leukemia earlier than in the past.

Adolescent↗
PubMed1994

Incidence of chronic lymphocytic leukemia in Olmsted County, Minnesota, 1935 through 1989, with emphasis on changes in initial stage at diagnosis.

OBJECTIVE: To determine whether the stage at the time of diagnosis of chronic lymphocytic leukemia (CLL) had changed during a 55-year period. DESIGN: We conducted a study of the cohort of residents of Olmsted County, Minnesota, who had been diagnosed as having CLL during the period from 1935 through 1989. MATERIAL AND METHODS: By analysis of medical records, patients with CLL were characterized by Rai stage, absolute lymphocyte count, age at diagnosis, need for therapy, and reported cause of death in nonsurvivors. Trends for these variables were analyzed by decade throughout the study period. RESULTS: The overall annual incidence rate of CLL per 100,000 population in Olmsted County increased from 2.6 in the 1935 through 1944 period to 5.4 in the 1975 through 1984 period; however, the increasing rate was found only for those 50 years of age or older and was especially dramatic for those 75 years old or older. Analysis of Rai stage over time demonstrated an increase in the proportion of cases diagnosed as Rai stage 0. In addition, the median absolute lymphocyte count decreased, the median time to initiation of therapy increased, and the median age of patients with Rai stage 0 CLL at the time of diagnosis increased over time. Overall, 54% of patients had received therapy for CLL by the time of last follow-up. Among the nonsurvivors, CLL was documented as the underlying or a contributing cause of death in 69%. CONCLUSION: The overall increase in CLL was thought to be due to enhanced methods of early diagnosis and improved health care for the elderly population. Thus, artifact may best explain the observed trend, although we cannot exclude the possibility of an actual increase in incidence rates over time.

Adult↗
PubMed1994

Bilateral cerebral mediofrontal hypoactivity in Tc-99m HMPAO SPECT imaging.

Fifteen patients who had bilateral mediofrontal hypoactivity and 30 control subjects without this SPECT anomaly underwent Tc-99m HMPAO brain SPECT imaging. Bilateral mediofrontal hypoactivity was found in various neurologic disorders, including subcortical arteriosclerotic encephalopathy, lacunar state, chronic alcoholism, progressive nonvascular dementia, carbon monoxide poisoning, and diabetes mellitus. This SPECT abnormality was, however, specifically associated with three clinical signs: motor disabilities predominating in the lower limbs, urinary incontinence, and akinetic mutism.

Akinetic Mutism↗