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Biomedical subjects

J Hakim

Publications and source records attributed to J Hakim.

At least 145 records · Page 8Linked to original sources
PubMed1981

The liver-protective enzymes against reduced forms of oxygen in phenobarbital-treated rats.

It is well known that phenobarbital treatment increases the production of superoxide anion by liver microsomes. Since the toxicity of superoxide anion and of its product, hydrogen peroxide, is well documented we measured the activities of the liver enzymes which protect the cell against the reduced forms of oxygen and the microsomal content of lipoperoxides in phenobarbital-treated rats. It was found that no lipoperoxides accumulate in the microsomes and that glutathione peroxidase, glutathione reductase activities, and the peroxidative activity of cytochrome P-450 were increased while catalase and superoxide dismutase activities were not modified.

Animals↗
PubMed1980

[Physiology and pathology of bactericidal activity in human polymorphonuclear neutrophils (author's transl)].

Blood polymorphonuclear neutrophils defend man against aggressions from pathogens. Under the combined influence of granulocytic and non-granulocytic factors, the defensive process develops by steps: the neutrophil moves towards the pathogenic organism which, one reached, is engulfed and killed. The killing systems of the cell are either oxygen-dependent or independent. the oxygen-dependent system is triggered off by stimulation of the cell membrane and involves various reactions, including cyanide-resistant oxygen consumption, production of activated oxygen, oxygen peroxide and halogenisation of the pathogen membrane. Impairment of the killing activity requires quantitative assessment of its various components in the presence of autologous or control serum with the view of: determining the origin (granulocytic or non-granulocytic) of the impairment, and identifying the step in oxygen metabolism that is affected. In the vast majority of non-granulocytic insufficiencies the cause lies in defective opsonins. In granulocytic insufficiencies, global failure of the system indicates chromic granulomatous disease, a syndrome that is now being dismembered. Defective halogenisation should lead to testing for deficiency of myeloperoxidase or abnormal degranulation. The non oxygen-independent bactericidal system, although highly effective in vitro, appears to be less important in vivo than the oxygen-dependent system. Little is known of its pathology.

Blood Bactericidal Activity↗
PubMed1979

Metabolic activity of human polymorphonuclear leucocytes: relation to ingestion rate.

The ingestion rate and oxygen-dependent metabolic activities of normal human polymorphonuclear leucocytes were measured with heat-killed Klebsiella as the particle. Since the experimental conditions were similar for each measurement, it was possible to make direct correlations between each oxygen-dependent reaction and (1) ingestion rate and (2) the other oxygen-dependent reactions. In the controls, oxygen-uptake was more reliably correlated (r = 0.960) with ingestion rates than with (in order of reliability) hydrogen peroxide produced (r = 0.860) and iodination (r = 0.858 and 0.813 for 100 and 20 micromol/l iodide respectively). Hydrogen peroxide production (r = 0.988), nitroblue tetrazolium reduction (r = 0.969) and cytochrome c reduction (r = 0.862) were more reliably correlated to oxygen-uptake than to ingestion rate, and iodination was better related to hydrogen peroxide production (r = 0.90 and 0.819 for 100 and 20 micromol/l iodide respectively) than to ingestion rate. From these findings it was possible to locate primary defects in abnormal polymorphonuclear leucocytes from individual patients with pyogenic infections, idiopathic refractory anaemia or idiopathic oesteomyelofibrosis with splenomegaly, even when several deficiencies existed.

Anemia↗
PubMed1978

NADPH-oxidation activities in subcellular fractions isolated from resting or phagocytozing human polymorphonuclears.

Using a fluorometric assay for the determination of oxidized pyridine nucleotides (NAD[P]+), total and cyanide-resistant NADPH-oxidative activities have been measured in subcellular fractions isolated from resting and phagocytosing human polymorphonuclears. Enzymatic activies responsible for the oxidation of the NADPH have been recovered in the heavy particles (15,000g/15 min), the low-density particles (100,000g/30 min), and the cytosolic fraction. Stimulation of the cells with opsonized zymosan had a different effect on the NADPH-oxidative activities of these subcellular fractions, which suggests the involvement of various types of enzymatic systems in the oxidation of NADPH. The cytosolic fraction interacted strongly with the enzymatic activities occurring in the sedimentable fractions and is therefore thought to play a central role in the regulation of the activation of the oxidative metabolism associated with phagocytosis.

Cell Fractionation↗