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Biomedical subjects

G Schaison

Publications and source records attributed to G Schaison.

At least 109 records · Page 6Linked to original sources
PubMed1991

Stimulatory effect of thyroid hormone on RA-induced granulocytic differentiation in leukemic cells.

Retinoic acid, vitamin D3, and dexamethasone are known inducers of myeloid leukemic cell differentiation. Recent evidence indicates that these drugs mediate their biological effects through binding to a nuclear receptor which belongs to the steroid/thyroid hormone receptor superfamily. This paper shows that the ligands of the other receptors of this family, estrogens, progesterone, androgens and thyroid hormone, do not induce leukemic cell differentiation. However, thyroid hormone potentiates, by one order of magnitude, the dose-response effect of retinoic acid in HL-60 cells.

Cell Differentiation↗
PubMed1991

Anterior and posterior hypopituitarism with pituitary stalk abnormalities.

Hypopituitarism and diabetes insipidus are often idiopathic conditions. A retrospective study of 6 cases of diabetes insipidus and 8 cases of partial or global idiopathic anterior hypopituitarism has shown that MRI is of considerable value to detect abnormalities of the pituitary stalk or hypothalamo-pituitary "relay". On the basis of MRI findings, some cases of idiopathic hypopituitarism can now be grouped together in a new entity which may be called hypopituitarism due to neonatal transection of the pituitary stalk.

Adolescent↗
PubMed1990

Late luteal administration of the antiprogesterone RU486 in normal women: effects on the menstrual cycle events and fertility control in a long-term study.

Twelve regularly cycling women, with contraindications to other methods of contraception, received RU486 (Roussel UCLAF, Romainville, France), once a month as a method of fertility control. The study was designed for 18 consecutive cycles. Each patient recorded basal body temperature, detected urinary luteinizing hormone peak, and collected saliva samples during each luteal phase for progesterone (P) determinations. A single dose of RU486, 600 mg, was given on the day before the expected date of the menses and 8 days later in case of continuing pregnancy after the first dose. Blood samples were collected for estradiol, P, and beta-human chorionic gonadotropin analyses on these two occasions. The compliance was poor and the results of only 137 cycles were obtained. The menstrual cyclicity was not significantly modified during this long-term study. Of the 137 cycles, 22 pregnancies occurred (16%), and 4 (18.2%) were not interrupted by the second dose of RU486. Thus, because of the high failure rate, use of RU486 at the time of the natural P withdrawal cannot be advocated as a "once-a-month" contragestive agent.

Adult↗
PubMed1990

Prevention of gram-positive and Candida albicans infections using teicoplanin and fluconazole: a randomized study in neutropenic children.

We have shown that the combination of teicoplanin (T) and ceftriaxone (C) given once daily as first-line empirical antimicrobial therapy is very effective (85%) and safe in febrile neutropenic children (ICAAC, 1988). Like others (ICAAC, 1989) we have stressed the new life-threatening problems with Streptococcus mitis and Strep. sanguis. Considering the regular sensitivity of Gram-positive organisms to T, it is possible that the introduction of the glycopeptide at the onset of aplasia may be helpful. The high incidence of fungal infection or superinfection supports the routine use of an effective antifungal agent when fever is still present or relapse occurs. Our study was designed to assess the prevention of (1) staphylococcal and streptococcal infections using T when the central catheter is being placed, and (2) candida infection by the simultaneous use of a new anti-mycotic agent fluconazole (F) administered once-daily. Patients were randomized into two arms of the study. Arm A received T 6 mg/kg/d and F 3 mg/kg/d starting when the catheter was put in place. If fever occurred, C 50 mg/kg/d and amikacin (A) 15 mg/kg/d were added and T increased to 10 mg/kg/d. If a febrile relapse occurred, amphotericin B was added. In arm B the combination of the three agents T 10 mg/kg/d, C 50 mg/kg/d and A 15 mg/kg/d was started only if there was fever. Amphotericin B was used in febrile relapses. Forty-six patients were eligible (23 in each arm; no statistically significant differences between the two groups). The mean age of the patients was 8 years and mean duration of aplasia 23 and 24 d. Results were as follows: arm A the duration of T + F alone was 10 d, 22 patients had a febrile episode with 1 Gram-positive, 11 Gram-negative and one candida strain isolated in eight patients. C + A were effective in 72% of these patients. There were no deaths. In arm B, fever occurred in all patients during the first 6 d, with eight Gram-positive and six Gram-negative organisms isolated in nine patients. C + T + A were successful in 83% of patients. A bacterial superinfection was documented in four patients, candida superinfection in seven patients and one patient died from Candida parakrusei septicaemia. When the total amount of C and A used in both arms was compared, there was a reduction in 20% of the two agents in arm A, but T was equivalent in both arms. Treatment was well tolerated in both arms.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1990

Syndromes of inappropriate macrophage activation in childhood.

The concept of inappropriate macrophage activation (IMA) embraces the clinicopathologic conditions associated with non-malignant lymphohistiocytic proliferation: familial lymphohistiocytosis (FLH) and hemophagocytic syndromes associated with viral, bacterial, fungal or parasitic infections in both immunodeficient and immunocompetent patients. IMA is also observed during the clinical course of primary immunodeficiencies (Chediak Higashi). The mechanisms of IMA are still unknown. Prognosis varies according to the immune status of the patients but is often very poor. Steroids but principally VP16-213 can slow the macrophage hyperactivation. Allogenic bone marrow grafting is indicated in FLH.

Arthritis↗
PubMed1990

Detection of minimal residual disease in leukemias: a critical approach.

The detection of minimal residual disease (MRD) represents a major goal in leukemias with great potential applications: identification of patients at high risk of relapse, earlier detection of relapses, possible improvement of autologous bone marrow transplantation (determination of the best time for bone marrow harvest and assessment of its quality). Theoretical requirements for a model of MRD detection exist and are recalled. Numerous methods (cytology, immunology, cytogenetics, clonogenic assays, molecular biology) have been used. All share limitations which may concern sensitivity, specificity, reproducibility, conveniency. Progresses will be brought by more sophisticated methods in immunology (double staining with or without flow cytometry) and above all molecular biology (revolutioned by polymerase chain reaction applications).

Antibodies, Monoclonal↗
PubMed1990

[Efficacy of the combination of ceftazidime/vancomycin in the first line treatment of infection in neutropenic children].

UNLABELLED: Infection is the first reason of mortality in children with bone marrow aplasia. It justifies the immediate treatment initiation before bacteriological cultures results. First line probabilistic treatment must have a bactericidal activity on the pathogens and must be atoxic. The empirical therapy consisted of ceftazidime 100 mg/k/d and vancomycine 40 mg/k/d three times a day. We treated 41 patients, ranged from 0.5 to 17 years (mean 9.5 years). 27 lymphoblastic leukaemias, 10 myeloblastic leukaemias, 4 lymphomas, presenting post therapeutic prolonged aplasia: PMN less than 500/mm3. 23 strains were isolated from 15 patients. 12 Gram+: 7 ceftazidime sensitive, 12 vancomycine sensitive and 11 Gram-: 10 ceftazidime sensitive. Only one is resistant to ceftazidime + vancomycine. Apyrexia was obtained in less than 48 hours in 36 patients. Mean treatment duration was 16 days. Hyperthermia relapsed 17 times and was susceptible to ampho B ten times, although no candida was isolated. When ceftazidime + vancomycine combination failed, other antibiotic treatment was ineffective. There were 4 superinfections (2 in blood, 1 enteric, 1 pharyngeal) and 2 germs were ceftazidime resistant. IN CONCLUSION: ceftazidime + vancomycine combination is a very effective treatment of infection in the neutropenic children: 88% success. 95% of the germs are sensitive to, at least, one of the 2 antibiotics. There are very few superinfections. Tolerance is excellent.

Adolescent↗
PubMed1990

Monosomy-7 in childhood hemopoietic disorders.

Acquired pure monosomy-7 is associated with various myeloproliferative disorders (MPD), myelodysplasias (MDS), and acute myeloblastic leukemias (AML) in children and a poor prognosis. A series of 14 malignant blood disorders with pure monosomy-7 in children (eight MPD, two refractory anemia with excess of blasts, (RAEB), and four AML) is reported and compared with cases in the literature. The median age is significantly different in the patients with MPD and those with MDS or AML: 23, 80.5, and 112 months, respectively. The outcomes of MPD and RAEB are characterized by a high risk of rapid blastic transformation and resistance to polychemotherapy. Bone marrow transplantation (BMT) seems to be the best treatment, and one survival of two years in complete remission after autologous BMT in a child with AML is reported. Several myeloid cell lineages are involved in the proliferation, which partly explains the difficulties of cytologic classification and suggests that a pluripotent stem-cell is at the origin of the disease.

Adolescent↗
PubMed1990

[Unusual cause of ascites: the POEMS syndrome].

A 39-year-old woman presented with polyneuropathy, hepatomegaly, splenomegaly, endocrinopathy, monoclonal protein and skin changes, several of the many clinical features of the recently described POEMS syndrome. In addition, she had a Castleman's disease (angiofollicular lymph node hyperplasia). In this case ascites was a main presenting feature. Thus, the POEMS syndrome must be added to the list of rare causes of ascites. Electron microscopy of the liver showed perisinusoidal fibrosis.

Adult↗
PubMed1989

[GnRH and its analogs--structure, mechanism of action and therapeutic applications].

In the last decade, much has been learned about the physiology and cellular biology of GnRH. In addition more than 2000 analogs agonists and antagonists have been synthesized. The GnRH precursor cDNA has been cloned from human placenta and hypothalamus mRNA's. The GnRH gene is located on the short arm of chromosome 8. The mechanism of action of GnRH requires Ca and its two intracellular receptors calmodulin and protein kinase C. The physiological effect of GnRH is to induce the release of both gonadotropins and to increase the alpha and beta subunit mRNA. In addition, GnRH stimulates terminal glycosylation of LH and FSH. Pulsatile GnRH exposure induces an up regulation of the receptors. In contrast continuous GnRH or GnRH agonist administration induces a receptor loss and a pituitary desensitization. The process of desensitization is unclear and requires some post receptor events which remain to be elucidated. Changes in the aminoacid composition of GnRH result in 2 classes of analogs agonists and antagonists. Both are used to induce a reversible medical castration. GnRH agonists lead to an initial rise in gonadotropins and gonadal steroid secretion. They are not able to suppress bioactive FSH. In contrast, GnRH antagonists compete with GnRH for its receptors and have an immediate and sustained suppressive effect on LH and FSH secretion. GnRH analogs are useful tools to study the gonadotropin regulation.

DNA↗
PubMed1989

Effects of a pure antiandrogen on gonadotropin secretion in normal women and in polycystic ovarian disease.

To assess the role of androgens in gonadotropin regulation in women, we studied the effects of a pure nonsteroidal antiandrogen, Anandron (Cassenne, Paris, France). Nine normally cycling women (group 1) with acne and/or seborrhoea and nine patients with polycystic ovarian disease (PCOD) (group 2) received Anandron (100 mg twice a day) and a placebo. Both treatments were administered orally, in a cross-over randomized design, for two consecutive cycles (group 1) or months (group 2) separated by one cycle or 1 month. Luteinizing hormone (LH) pulse frequency and amplitude (cluster analysis), basal and gonadotropin-releasing hormone (GnRH)-stimulated plasma LH/follicle-stimulating hormone (FSH) levels were determined on day 5 of each treatment or placebo cycle. On days 5, 10, 20, and 24 of each cycle or month, plasma estradiol (E2), estrone (E1), testosterone (T), dihydrotestosterone (DHT), androstenedione (A), dehydroepiandrosterone sulfate (DHAS), sex hormone-binding globulin (SHBG) levels, and urinary androstanediol glucuronide (3 alpha-diol G) were measured. Plasma progesterone (P) levels were determined on days 20 and 24 of each cycle (group 1) and on days 5, 10, 20, and 24 (group 2). In both groups, seborrhea and acne decreased markedly within the first month and practically disappeared after 2 months of Anandron treatment. No adverse side effects were reported. None of the normal patients had any disturbance of menstrual cycles as assessed by basal body temperature shift, ultrasonography, and plasma P levels. In PCOD patients, cycles remained anovulatory.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effects of vasoactive intestinal polypeptide, TRH, and dopamine on prolactin secretion in estrogen-primed postmenopausal women.

Prolactin secretion is influenced by at least three important hypothalamic neurotransmitters: TRH, vasoactive intestinal polypeptide and dopamine. The purpose of this study was to determine whether, in estradiol-primed postmenopausal women, the PRL response to TRH, vasoactive intestinal polypeptide, and dopamine differed. Ten postmenopausal women were studied during treatment with estradiol benzoate at a dose of 0.625 mg per day during 15 days. TRH (200 micrograms iv), saline infusion, vasoactive intestinal polypeptide (75 micrograms infused iv during 15 min), coadministration of vasoactive intestinal polypeptide and TRH, and dopamine (4 micrograms.kg-1.min-1 iv for 3 h) were administered for 5 consecutive days before and during the last 5 days of estradiol benzoate treatment. Before estradiol benzoate administration, the PRL, response to TRH was significantly greater than that of vasoactive intestinal polypeptide. Estradiol benzoate treatment increased significantly the PRL release induced by TRH (p less than 0.01), but did not modify the response to vasoactive intestinal polypeptide. At the end of estradiol benzoate treatment, the maximal increase in PRL after the combined (vasoactive intestinal polypeptide + TRH) test was greater than that obtained with TRH alone and occurred earlier (p less than 0.04). Dopamine suppressed PRL secretion to a similar extent after estradiol benzoate treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Dopamine↗
PubMed1989

Bone marrow transplantation for genetic and metabolic disorders.

Bone marrow transplantation (BMT) was primarily used for the treatment of hematologic malignancies and aplastic anemias. BMT has been successfully applied as curative treatment in a series of lethal congenital disorders but among more than 1000 inherited metabolic diseases only 20 of them can be corrected by transplantation. The inborn error must be expressed in the stem cells. The genetic disorders that can be cured include congenital immune deficiencies, osteopetrosis, and congenital lysosomal storage diseases, mucopolysaccharidosis and lipidosis. BMT with an HLA matched donor is successful in 60% of patients with severe combined immune deficiency and Wiskott Aldrich syndrome. Results are good in osteopetrosis if BMT is performed early. Encouraging results have been reported in Hurler disease and in Gaucher disease.

Bone Marrow Transplantation↗
PubMed1989

[Parvovirus infections in children with hemolytic anemia].

Acute episodes of erythroblastopenia in children with chronic hemolytic anemias have been recognized for a considerable length of time. In 1981, a small virus with a single strand of DNA, parvovirus B 19, was identified as the causative agent in most such episodes. Other diseases have been ascribed to parvovirus B 19, including erythema infectiosum or fifth disease, polyarthralgia, fetal death. Schonlein-Henoch disease, and bone marrow aplasia. In acute attacks of erythroblastopenia, anemia is the most prominent manifestation, but coexistence of neutropenia and thrombopenia has been reported. Hematologic disorders last for approximately ten days. The diagnosis of recent parvovirus B 19 infection rests on detection of specific IgM antibodies, or direct visualisation of the virus by electron microscopy. More recently, detection of the viral genome using molecular hybridization techniques has been achieved. In vitro studies have confirmed the inhibiting effect of parvovirus B 19 on red cell line progenitors, particularly CFU-E, but the exact mechanism of the inhibition remains uncertain. Other diseases due to parvovirus B 19 or other parvoviruses probably remain to be discovered.

Anemia, Hemolytic↗