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Biomedical subjects

J Humbert

Publications and source records attributed to J Humbert.

At least 19 recordsLinked to original sources
PubMed2002

Analysis and quantification of prescribing and transcription errors in a paediatric oncology service.

OBJECTIVE: To analyse and quantify the omission errors linked to physicians' prescribing and errors linked to nurses' transcription and to identify the type and frequency of factors associated. No pharmacological factors are taken into account. DESIGN: Analysis of physicians' prescriptions and nurses' transcriptions in chemotherapeutic treatments (20 patient files) and non-chemotherapeutic treatments (20 patient files); retrospective study. SETTING: Paediatric onco-haematology unit. MAIN OUTCOME MEASURES: Categorisation of physicians' prescriptions as complete or incomplete, categorisation of the various nurses' transcriptions as correct or incorrect. RESULTS: Physicians' prescriptions were complete for 61.6% of non-chemotherapy treatments. As each prescription is transcribed twice, two nurses' transcription sheets are filled in by the nurses. At the first transcription 79.3% of non-chemotherapy prescriptions and 88.2% of chemotherapy prescriptions were transcribed correctly, while in the second sheet these percentages were respectively 96.2% and 93.7%. CONCLUSIONS: Too many sheets of paper generate confusion and increase the risk of errors. The several transcriptions are, in both types of treatment, sources of errors. The problems identified in this study allowed us to open a discussion as how to improve the physicians prescriptions and the nurses' transcription sheets.

Child↗
PubMed2001

Stroke in hemoglobin (SD) sickle cell disease with moyamoya: successful hydroxyurea treatment after cerebrovascular bypass surgery.

An 11-year-old boy with hemoglobin sickle disease (HbSD), bilateral stenosis of the intracranial carotid arteries, and moyamoya syndrome had recurrent ischemic strokes with aphasia and right hemiparesis. His parents (Jehovah's Witnesses) refused blood transfusions. After bilateral extracranial-intracranial (EC-IC) bypass surgery, hydroxyurea treatment increased hemoglobin F (HbF) levels to more than 30%. During a follow-up of 28 months, flow velocities in the basal cerebral arteries remained stable, neurologic sequelae regressed, and ischemic events did not recur. This is the first report of successful hydroxyurea treatment after bypass surgery for intracranial cerebral artery obstruction with moyamoya syndrome in sickle cell disease. The patient's religious background contributed to an ethically challenging therapeutic task. (Blood. 2001;97:2165-2167)

Anemia, Sickle Cell↗
PubMed2001

Hypothesis for generation of the unstable Hb Bucuresti (beta 42 Phe-->Leu) mutation.

INTRODUCTION: Unstable hemoglobin disorders are characterized by a congenital, mostly familial chronic hemolytic anemia with episodes of severe hemolysis during febrile illnesses. Usually, isopropanol and heat stability tests lead to the diagnosis which is confirmed by protein and gene sequencing. Generation of the mutations is still a subject of controversy. PATIENT, MATERIALS AND METHODS: We describe a 6-year-old Swiss child with congenital hemolytic anemia and a negative family history. Hemoglobin was studied by IEF, HPLC reverse phase chromatography, heat stability and isopropranol tests. DNA was sequenced in both coding and non-coding strands. RESULTS: An unstable Hb was diagnosed on the basis of positive heat stability and isopropranol tests. The TTT-->TTG mutation at codon 42 corresponding to a Phe-->Leu substitution was found on DNA sequencing. Paternity was confirmed indicating that we are dealing with a new mutation. CONCLUSION: So far, three different mutations at codon 42 of the beta-chain, and two at the corresponding position of the alpha-chain have been described, all leading to a hemolytic anemia. These mutations can either represent random phenomena occurring at an important location in the heme pocket, or may be secondary to the two highly homologous zones present in this region. These homologous zones may indicate a hot spot for point mutations created by abnormal crossing over or formation of loops, and an imperfect DNA repair process.

Amino Acid Substitution↗
PubMed2001

Successful treatment of neonatal rhesus hemolytic anemia with high doses of recombinant human erythropoietin.

The authors report the use of high-dose recombinant erythropoietin (r-HuEPO) in a full-term newborn baby with severe postnatal rhesus hemolytic anemia (RHA). Hemoglobin (Hb) value and reticulocyte count at day 13 of life were 59 g/L and 234 x 10(9)/L, respectively. Three days after the r-HuEPO (870 U/kg/d) administration, reticulocyte count had increased more than 4-fold and Hb rose to 73 g/L. r-HuEPO was gradually decreased after 18 days of treatment. No major side effect was observed. In selected cases of severe anemia due to hemolytic disorders, transfusions may be avoided by the use of high doses of r-HuEPO.

Anemia, Hemolytic, Congenital↗
PubMed2001

Fatal myocardial aspergillosis in an immunosuppressed child.

A girl with resistant acute myeloid leukemia (AML) had a stem cell transplantation. Preceding transplantation, she had recurrent pneumonitis. No causative agent was identified. Despite several antibiotics including high-dose liposomal amphotericin-B, pulmonary infection progressed. Aspergillosis, always considered, could not be documented. She died from cardiac arrest on the second day after transplantation, with no forewarning of previous heart disease. Pericardial and myocardial aspergillosis was an autopsy finding. Pericardial and myocardial aspergillosis, rare manifestations of systemic aspergillosis, should be considered in any immunocompromised patient with long-lasting pulmonary infection, even in the absence of specific cardiac findings.

Amphotericin B↗
PubMed2001

Nurse practitioner preferences for distance education methods related to learning style, course content, and achievement.

The relationships among multiple distance delivery methods, preferred learning style, content, and achievement was sought for primary care nurse practitioner students. A researcher-designed questionnaire was completed by 86 (71%) participants, while 6 engaged in follow-up interviews. The results of the study included: participants preferred learning by "considering the big picture"; "setting own learning plans"; and "focusing on concrete examples." Several positive associations were found: learning on own with learning by reading, and setting own learning plans; small group with learning through discussion; large group with learning new things through hearing and with having learning plans set by others. The most preferred method was print-based material and the least preferred method was audio tape. The most suited method for content included video teleconferencing for counseling, political action, and transcultural issues; and video tape for physical assessment. Convenience, self-direction, and timing of learning were more important than delivery method or learning style. Preferred order of learning was reading, discussing, observing, doing, and reflecting. Recommended considerations when designing distance courses include a mix of delivery methods, specific content, outcomes, learner characteristics, and state of technology.

Achievement↗
PubMed2000

Electron microscopic improvement in the study of diarrheagenic Escherichia coli.

In the versatile single species of Escherichia coli, the diarrheagenic group displays a remarkable array of virulence traits. These comprise microbial attachment, production of secretory endotoxins or cell-destroying cytotoxins, direct epithelial cell invasion, and localized effacement of the epithelium. The knowledge of how enteric E. coli induce disease has become increasingly important in the world, because of new pathogen emergence, increasing threats of drug resistance, and growing awareness of their importance in malnutrition and diarrhea. Numerous research programs have demonstrated various mechanisms of pathogenesis. We point out how some pathogens are able to develop intercourse with their host through subversion of its cytoskeleton and signaling processes without toxin secretion or heavy invasiveness. In that domain, the cellular biology of infected cells owes fundamental data to the electron microscopic approach. Combined with advances in microbiology and molecular biology, this approach may provide answers to many unanswered questions.

Animals↗
PubMed1999

[Common anemias in neonatology].

We describe the four most common groups of neonatal anemia and their treatments, with particular emphasis on erythropoietin therapy. The hemolytic anemias include the ABO incompatibility (much more frequent, nowadays, than the Rh incompatibility, which has nearly disappeared following the use of anti-D immunoglobulin in postpartum Rh-negative mothers), hereditary spherocytosis and G-6-PD deficiency. Among hypoplastic anemias, that caused by Parvovirus B19 predominates, by far, over Diamond-Blackfan anemia, alpha-thalassemia and the rare sideroblastic anemias. "Hemorrhagic" anemias occur during twin-to-twin transfusions, or during feto-maternal transfusions. Finally, the multifactorial anemia of prematurity develops principally as a result of the rapid expansion of the blood volume in this group of patients. Erythropoietin therapy, often at doses much higher than those used in the adult, should be seriously considered in most cases of non-hypoplastic neonatal anemias, to minimise maximally the use of transfusions.

Adult↗
PubMed1999

Local low-dose urokinase treatment of acquired intracardiac thrombi in preterm infants.

We report three cases of intracardiac thrombi in preterm infants of very low birth weight, in whom local low-dose urokinase treatment achieved complete thrombolysis without any signs of systemic fibrinolytic activity or side-effects. This new treatment strategy seems to be safe, requires minimal monitoring of fibrinolytic activity, and may be a new option for thrombolysis in high-risk patients such as premature infants, patients recently operated on, and patients presenting with other contra-indications for systemic fibrinolytic therapy.

Female↗
PubMed1999

Induction of immune tolerance with recombinant factor VIII in haemophilia A patients with inhibitors.

We report on 11 patients (nine unrelated and a brother pair) with severe haemophilia A and factor VIII (FVIII) inhibitor, in whom immune tolerance (IIT) was induced with recombinant FVIII (r-FVIII). Their age ranged from 11 months to 47 years. The number of exposure days (ED) at inhibitor detection varied from 11 to 130. Nine of the 11 patients were high responders ¿>10 Bethesda units (BU) with peak inhibitor levels ranging from 10 to 566 BU. The other two were low responders with peak levels between 0.7 and 2 BU. Before inhibitor detection, the patients had been receiving products of various purities. The IIT regimens were very heterogeneous, and the treatment schedule varied from a short period with 50 IU kg-1 every 2 days, followed by 100 IU kg-1 every 2 days and then 220 IU kg-1 daily. The outcome was considered successful when the inhibitor level fell to 0.6 BU or lower after IIT treatment. The outcome overall was successful in nine out of 11 patients (81.8%), with the nine successful cases comprising seven of the nine high responders (77.8%) and the two low responders. Definite failure of IIT was observed in one high responder after two different IIT regimens. A second high responder is still on IIT treatment. All patients in whom IIT was successful are currently receiving r-FVIII on demand or prophylactically at various dosages. Despite the variability of the patient characteristics and the IIT schedules, this study demonstrates that r-FVIII represents an effective alternative for the eradication of inhibitors through IIT.

Adolescent↗
PubMed1999

[Falciform anemia and Plasmodium falciparum malaria: a threat to flap survival?].

Plasmodium falciparum malaria, a parasitic disease, and sickle cell anemia, a hereditary disease, are two diseases affecting erythrocyte cycle, occurring with a high prevalence in tropical Africa. They may induce microthrombosis inducing vaso-occlusion, organ dysfunction and flap necrosis. During the acute phase of Plasmodium falciparum malaria, destruction of parasitized and healthy erythrocytes, release of parasite and erythrocyte material into the circulation, and secondary host reaction occur. Plasmodium falciparum infected erythrocytes also sequester in the microcirculation of vital organs and may interfere with microcirculatory flow in the flap during the postoperative period. The lower legs of homozygous sickle cell anemia patients are areas of marginal vascularity where minor abrasions become foci of inflammation. Inflammation results in decreased local oxygen tension, sickling of erythrocytes, increased blood viscosity and thrombosis with consequent ischemia, tissue breakdown and leg ulcer. Tissue transfer has become the procedure of choice for reconstruction of the lower third of the leg although flaps may become necrotic. The aim of this study is to analyse circumstances predisposing to surgical complications and to define preventive and therapeutic measures. A review of the literature will describe the current research and the new perspectives to treat sickle cell anemia, for example hydroxyurea and vasoactive substances (pentoxifylline, naftidrofuryl, buflomedil).

Anemia, Sickle Cell↗
PubMed1998

Prognostic significance of sex in childhood B-precursor acute lymphoblastic leukemia: a Pediatric Oncology Group Study.

PURPOSE: In childhood B-precursor acute lymphoblastic leukemia (ALL), possible interactions among sex, time, and widely used prognostic factors (age, WBC count, and DNA index) were investigated for the first 5 years after diagnosis. PATIENTS AND METHODS: All eligible patients aged 1 to less than 22 years, registered between February 1986 and September 1994 in two B-precursor ALL studies from the Pediatric Oncology Group (POG), were included in the analysis. Cutpoints for age (3.0, 5.0, and 10.0 years), WBC count (10, 50, and 100 x 10(9)/L), and DNA index (DI; 1.16) were defined. Four time periods after diagnosis (years 1, 2, 3, and 4 and 5 combined) were selected for the study of prognostic significance over time. The cut-off date for analysis was April 1996. RESULTS: A total of 3,717 children (2,010 boys and 1,707 girls) were included in the outcome analysis. No major differences between the sexes were observed in age, duration of symptoms before registration, WBC count, hemoglobin level, platelet count, ploidy, presence of CNS disease at diagnosis, or induction failure rate. Event-free survival (EFS) differences between sexes became significantly different from 2 years following diagnosis. At 5 years, in all subsets analyzed, boys fared worse than girls, although not all differences were statistically significant. Major sex differences in EFS were observed in older children (10 to 22 years), in patients with intermediate WBC counts (10 to 50 x 10(9)/ L), and in children who fit both of these subgroups, in whom the 2-year EFS was almost 20% higher in girls than in boys, reaching a 38% difference at 5 years. CONCLUSION: This study shows an outcome interaction among sex, time, and commonly used prognostic variables. The important sex difference observed at 2 and 5 years suggests that more intensive consolidation and/or maintenance therapy in some boys with B-precursor ALL should be investigated.

Adolescent↗
PubMed1997

The importance of intermediate filaments in the adaptation of tissues to mechanical stress: evidence from gene knockout studies.

Research over the past few years on the function of intermediate filaments in cells in culture has not produced convincing results, because the key role of intermediate filaments is within tissues and at certain periods of development. Only recently the technique of gene knockout has been used to examine intermediate filaments in mice and has provided the first evidence that intermediate filaments are directly involved in cell resilience and the maintenance of tissue integrity. Knockout of the gene encoding keratin K8 is lethal in the embryo, and results in hepatic or intestinal lesions, while knockout of the K14 or K10 genes leads to rupture of stratified epithelia. Knockout of the gene encoding desmin causes the rupture of skeletal and cardiac muscle, and collapse of blood vessel walls. Knockout of the gene coding for GFAP leads to a loss of cerebral white matter, and knockout of the gene coding for vimentin causes degeneration of the cerebellar Purkinje cells. The results reveal the lack of compensation by another intermediate filament. Tissues without intermediate filaments fall apart; they are mechanically unstable, unable to resist physical stress, and this leads to cell degeneration. By maintaining the shape and plasticity of the cell, the intermediate filament network acts as an integrator within the cell space. The state of mechanical force imposed on a tissue or a cell can alter the shape of certain elements of the cytoskeleton and thus participate to the control of cell functions.

Adaptation, Physiological↗
PubMed1996

RU 3117 a steroidal compound with high affinity for sigma sites in rat testis membranes.

RU 3117 belongs to a new series of steroids which exhibited a high relative binding affinity (RBA) for (+)[3H]PPP sites in rat testis membranes; its RBA was about 40 times higher than that of progesterone. Furthermore, it is devoid of any binding to classical steroid receptors; therefore in order to study its binding parameters on rat testis membranes it was tritiated. [3H]RU 3117 bound at least two distinct sites with Ka values of 0.4 +/- 0.06 x 10(9) M(-1) and 1.3 +/- 0.2 x 10(7) M(-1). Using this marker, competition studies with cold haloperidol showed that a part of this binding was haloperidol-sensitive, whereas another part was haloperidol-resistant. Interestingly, progesterone described as a sigma ligand competes with [3H]RU 3117 binding, with an RBA of 1.6%. When haloperidol was preincubated (250 nM) with rat testis membranes, in order to mask the sigma sites, we observed that DTG (1,3-di-O-tolylguanidine) and haloperidol displayed a very low RBA (< 0.1%) and were not able totally to displace the [3H]RU 3117 binding up to 50 microM. Furthermore, benztropine exhibited a significant RBA of 19% but its displacement curve showed a plateau (500-50,000 nM). These results showed that part of the haloperidol-resistant sites was benztropine sensitive but another part was displaced neither by haloperidol nor by benztropine. The presence of these remaining binding sites was confirmed by preincubating a mixture of haloperidol and benztropine with testis membranes. Under these conditions, [3H]RU 3117 displayed a Ka of 1.0 +/- 0.01 x 10(7) M(-1), and we observed that these sites were recognized, up to now, only by the steroids RU 1968 and RU 54173 which are also devoid of any binding to classical nuclear steroid receptors.

Animals↗
PubMed1994

RU 58841, a new specific topical antiandrogen: a candidate of choice for the treatment of acne, androgenetic alopecia and hirsutism.

A new topically active non-steroidal antiandrogen, RU 58841 has been synthesized. It displays high affinity for the hamster prostate and flank organ (F.O.) androgen receptors. In vivo, when topically applied, it exerts a potent dose-dependent regression of F.O. area at a dose as low as 1 microgram/animal while being devoid of antiandrogenic activity on deep accessory sex organs and of any effect on testosterone level up to 100 micrograms/animal. In the same species, after subcutaneous administration, it induces at the dose of 300 micrograms/animal, a small decrease in F.O. area equivalent to that of 1 microgram applied topically and a weak systemic activity. In intact rats, no effects were observed up to 1 microgram/animal whatever the route of administration. These results suggest that RU 58841 might useful for the topical treatment of androgen-dependent skin disorders such as acne, androgenetic alopecia and hirsutism.

Acne Vulgaris↗