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Biomedical subjects

J Humbert

Publications and source records attributed to J Humbert.

At least 37 records · Page 2Linked to original sources

Transport proteins and acute phase reactant proteins in children with sickle cell anemia.

Transport proteins, acute-phase reactant proteins (APRP), hematology, and anthropometry were studied in 34 sickle cell disease (SCD) children (20 boys, 14 girls) and 27 controls without growth deficits (13 boys, 14 girls) [corrected]. The age range was 1/2 to 16 1/2 years. Weight deficits (< 80%) by Waterlow's classification were observed in 41% of SCD boys and 25% of SCD girls, and height deficits (< 90%) were observed in 25% SCD boys and 25% girls. Mean white blood cell counts were significantly higher (P < .001) and hematocrit and hemoglobin (Hb) lower (P < .005) in SCD children than in controls. Although both groups had similar mean levels of albumin, transferrin, and APRP, SCD children had significantly lower mean levels of retinol-binding protein (RBP) (P < .001) and retinol-prealbumin (P < .001). Retinol-binding protein levels were abnormal in 18 (53%) SCD children and in only 23% controls (chi 2 = 14.06; P < 0.005); transferrin levels were abnormal in 20% of SCD children and in none of the controls. Children with SC and SF Hb phenotype had normal mean levels of RBP, whereas those with S beta thal and SS phenotype had levels below normal. Growth-retarded children by weight and height had reduced mean levels of RBP and prealbumin compared with growth-normal SCD children. The implication of primary protein-energy malnutrition on growth retardation in SCD children is under study.

Acute-Phase Proteins↗

Desmin sequence elements regulating skeletal muscle-specific expression in transgenic mice.

During the development of the mouse embryo, desmin is one of the first muscle proteins detected in both the heart and the somites. The expression of the desmin gene differs from most other muscle genes, since it is initiated in replicating myoblasts and accumulates as the muscle differentiates. We have characterized a muscle-specific enhancer which directs the expression of desmin in vitro in the myoblasts and myotubes of C2 cells but not in non-myogenic cells. We report here on the generation and characterization of transgenic mice bearing a transgene in which the 1 kb DNA 5' regulatory sequence of the desmin gene is linked to a reporter gene coding for Escherichia coli beta-galactosidase (Des1-nlacZ). The enhancer activity of the desmin promoter is very strong and the reporter gene expression is easily detected in tissue sections. We have demonstrated that the regulatory elements present in the transgene Des1-nlacZ are sufficient to direct muscle-specific and developmentally regulated expression of nlacZ in skeletal muscles. Endogenous desmin expression and transgene activity were found to be correlated during the development of skeletal muscles. The transgene was expressed in the committed mononucleate myoblasts as well as in the myotubes. In addition, we have shown that the desmin-derived sequences direct a highly selective expression of nlacZ in cells that leave the somites and invade the limb bud, indicating that the cells that migrate from the somites are already predetermined for myogenesis. In contrast, smooth and cardiac muscle cells were beta-galactosidase negative both during embryonic and foetal development. Interestingly, the transgene was found to be expressed in the conduction system of the heart, which exhibits many features characteristic of skeletal muscles.

Animals↗

Cell cycle regulation of histone H1O in CHO cells: a flow cytofluorimetric study after double staining of the cells.

The regulation of histone H1O content throughout the cell cycle of non-synchronized Chinese hamster ovary (CHO) cells has been studied using double fluorescent staining and flow cytofluorometry. In exponentially growing cells, the amount of H1O was found to be proportional to the DNA content of the cells, indicating that the protein is synthesized throughout the cell cycle. However, when cells were arrested in G1 at saturation density the amount of H1O was greater than that found in G1 cells of the exponentially growing population. In contrast, the levels of H1-1 were the same for G1 cells of both populations. These results show that the regulation of H1O accumulation differs from that of other histones.

Animals↗

The in vitro effects of Newcastle disease virus on the metabolic and antibacterial functions of human neutrophils.

Live Newcastle disease virus (NDV) was used to investigate the in vitro effects of a viral infection on phagocytosis, chemiluminescence generation, superoxide production, oxygen consumption, NADPH-oxidase activity, and intracellular killing of bacteria by Ficoll-Hypaque separated human neutrophils. Phagocytosis of oil red O particles by NDV-treated PMN was inhibited by 50%. Chemiluminescence by PMN was inhibited 79% after zymosan stimulation and 86% after tetradeconyl phorbol acetate stimulation. Superoxide generation was inhibited by 68%. Oxygen consumption was inhibited in the presence of NDV by 37% after stimulation with phorbol myristate acetate, while membrane-associated NADPH-enzyme activity was decreased by 19%. The percent of surviving intracellular S. aureus was significantly elevated in NDV-treated PMN after 60 and 120 min of incubation. Purified bacterial neuraminidase markedly suppressed chemiluminescence, while neuraminic acid blocked the effects of the virus. These observations suggest that infections with myxoviruses may suppress a number of vital neutrophil functions. It appears that the effects may be partly mediated by the interaction of viral neuraminidase with the external neutrophil membrane.

Adult↗

Enkephalin-like products in embryonic chicken retina.

Using sensitive and highly specific radioimmunoassays, Met-enkephalin (Met-ENK) and Leu-enkephalin (Leu-ENK) have been shown to exist together in the retina of chicken embryo. After high performance liquid chromatography (HPLC), a fraction of the retinal extracts seems to be authentic Met-ENK. Following a G-50 filtration, the Met-ENK immunoreactivity has been found associated to three peaks, the lightest having an apparent molecular weight similar to that of the Met-ENK.

Animals↗

Early hospital discharge of children with fever and neutropenia: a prospective study.

PURPOSE: We report a prospective study on brief IV antibiotic therapy in selected children with cancer experiencing fever and neutropenia (FN) after chemotherapy. PATIENTS AND METHODS: All children with FN (T degree > or = 38 degrees C; ANC < 0.5 x 10(9)/L) were hospitalized for treatment with broad spectrum IV antibiotics. They were divided into three groups: group A (no infection), group B (clinically documented infection), and group C (bacteremia). Children in group A (and some children in group B) were discharged before recovery of neutropenia, if afebrile and in good condition. RESULTS: Eighty-eight consecutive episodes of FN occurred in 30 children. Children in group A (44 episodes; 50%) received IV antibiotics for a median of 3 days; on 25 occasions (57%), IV antibiotics were stopped before recovery of neutropenia. In children in group B (30 episodes; 34%), early discharge was allowed in eight cases of minor infections (27%); six received oral antibiotics. Two children (group A) were rehospitalized for recurrent FN but recovered without complications. CONCLUSION: In chemotherapy-induced neutropenia, children hospitalized for fever but without documented infections and some children with minor infections can cautiously be discharged before evidence of bone marrow recovery if afebrile and in good general condition.

Anti-Bacterial Agents↗

Trimethoprim-sulfamethoxazole salvage for refractory listeriosis during maintenance chemotherapy for acute lymphoblastic leukemia.

A 5-year-old boy with acute lymphoblastic leukemia (ALL) and intolerance to oral trimethoprim-sulfamethoxazole (TMP/SMX) had Listeria monocytogenes bacteremia and meningitis develop during maintenance chemotherapy. Despite prompt administration of IV amoxicillin/gentamicin and microbiologic clearance of the bloodstream, the patient had no response to therapy after a course of 7 days. Intravenous TMP/SMX (10 mg/kg per day of TMP) was added to the antibiotic regimen after desensitization. Fever and meningeal signs rapidly resolved, and the patient was ultimately cured. Amoxicillin and gentamicin, although highly active and synergistic in vitro against L. monocytogenes, have limited intracellular penetration and activity. In contrast, TMP/SMX has bactericidal extracellular and intracellular activity against Listeria and excellent central nervous system penetration, and thus may be effective for the treatment of refractory listeriosis.

Aminoglycosides↗