Purification of cytochrome b-245 from human neutrophils

The low potential cytochrome b (b-245) of the microbicidal oxidase of phagocytic cells has been purified from neutrophils from patients with chronic myeloid leukaemia. Cells were homogenized in the presence of proteinase inhibitors and centrifuged to remove the cytoplasm. The pellets containing membranes, granules and other organelles (15 mg/ml) were then washed with buffered sodium cholate (5 mg/ml). Residual pellets were subsequently solubilized with the non-ionic detergent Triton N 101 (10 mg/ml) which extracted about 60% of the cytochrome b. About 10% of the cytochrome b was of mitochondrial origin which was removed on a column of n-amino-octyl-Sepharose that did not adsorb cytochrome b-245. Cytochrome b-245 was chromatographed on a column of heparin-agarose and eluted with NaCl to give a peak specific content of 11-16 nmol of cytochrome b-245/mg of protein, representing a 140-200-fold purification with a recovery of 15%. This technique results in the purification of approx. 100-150 nmol of highly purified cytochrome b-245 from (3-5) X 10(11) cells within 4 days. The most purified material gave a broad band with an apparent Mr of between 68 000 and 78 000 on sodium dodecyl sulphate/polyacrylamide gel electrophoresis, but gel filtration indicated an aggregated form of the protein in Triton N101 . Purified protein (14 nmol of haem/mg of protein) did not contain FAD or FMN and had no NADPH-dependent O2--generating activity.

Changes in the subcellular distribution of the cytochrome b-245 on stimulation of human neutrophils

Cytochrome b-245 of neutrophils has a bimodal distribution in sucrose density gradients. The lighter component (d = 1.14) is shown to be associated with the plasma membrane by the similarity between its density and that of markers of this organelle, as well as a parallel increase in the density of the cytochrome and plasma membrane after treatment with digitonin or dimethyl suberimidate. The cytochrome b-245 of monocytes and cytoplasts, the latter produced by the removal of nuclei and granules from neutrophils, was located only in the plasma membrane. The denser peak of cytochrome (d = 1.19), which contained approximately half of the cytochrome b of neutrophils, had a similar density-distribution profile to the specific granules. After hypo-osmotic disruption of this denser material, the cytochrome distributed with the density of membranes, suggesting an original location within the membrane of the intracellular structure. Redistribution of the cytochrome from the granules to the membranes was observed after stimulation of respiratory activity with soluble agents or opsonized particles. This translocation is not responsible for activation of the oxidase system. There was poor agreement between the kinetics of the transfer of cytochromes from the dense component to the membranes, and degranulation of specific-granule contents, suggesting that the cytochrome may be located in another intracellular structure or that its localization becomes further modified after granule fusion.

The subcellular localization of ubiquinone in human neutrophils

Ubiquinone-10 has recently been proposed as a component of the microbicidal oxidase system of neutrophil leukocytes [Crawford & Schneider (1982) J. Biol. Chem. 257, 6662-6668]. We have determined the subcellular localization of ubiquinone and could detect it only in the mitochondrial fractions. It was not enriched in phagolysosomes which were enriched in O2-. generating activity and cytochrome b-245. It is proposed that ubiquinone is unlikely to play a direct role in the electron transport chain located in the plasma membrane which functions to produce microbicidal oxygen radicals.

A variant form of X-linked chronic granulomatous disease with normal nitroblue tetrazolium slide test and cytochrome b

Chronic granulomatous disease was diagnosed in a boy who suffered from severe generalized infections. Family investigations revealed the inheritance of the disease to be X-linked. However, unlike other cases of X-linked chronic granulomatous disease, the membrane oxidase of the neutrophils from this patient was not totally defective and sufficient activity was left to result in a normal phorbol myristate acetate-stimulated nitroblue tetrazolium slide test. Also, unlike the usual findings in X-linked chronic granulomatous disease, cytochrome b was present in normal amounts in the neutrophils from this patient. The cytochrome was normal, judged from its midpoint potential of -245 mV and its ability to bind CO. It is thus apparent that X-linked chronic granulomatous disease may result from at least two different defects and that the phorbol myristate acetate stimulated nitroblue tetrazolium slide test fails to detect some cases.

The kinetic measurement of phagocyte function in whole blood

A technique has been developed for the kinetic measurement on the same blood sample of a variety of functions of phagocytic cells. Adherence to glass, the clearance of a mixture of microorganisms and their subsequent solubilisation, and the secretion of granule contents from the cells were determined. The numbers of residual viable intracellular staphylococci were measured at the completion of the study. These methods were used to investigate phagocyte function in 33 normal subjects and 6 patients with chronic granulomatous disease.

Absence of cytochrome b-245 in chronic granulomatous disease. A multicenter European evaluation of its incidence and relevance

The heme-containing protein cytochrome b-245 has been proposed as a primary component of the microbicidal oxidase system of phagocytes that normally generates superoxide-free radicals but when defective is associated with chronic granulomatous disease. We measured this cytochrome in granulocytes from 27 patients with chronic granulomatous disease and from 64 members of their families. It was undetectable in all 19 of the men in whom the defect appeared to be located on the X chromosome. Female relatives who were heterozygous carriers had reduced concentrations of the cytochrome and variable proportions of cells that were unable to generate superoxide; these two characteristics were closely related (r = 0.93 in the 16 mothers and 0.85 in all 24 carriers, P less than 0.001). In contrast, in all eight patients (seven women) with a probable autosomal recessive inheritance the cytochrome was present but nonfunctional. The properties tested, including midpoint potential, carbon monoxide binding, and organelle distribution, were normal, but the cytochrome did not undergo reduction on cellular stimulation. Thus, absence or malfunction of the cytochrome b-245 may be the causal molecular defect in chronic granulomatous disease, implicating it in the microbicidal oxidase system.

Iodination by stimulated human neutrophils. Studies on its stoichiometry, subcellular localization and relevance to microbial killing

Myeloperoxidase of phagocytic leucocytes is thought to utilize H2O2 to oxidize halides, which then react with and kill ingested microbes. This hypothesis was based largely on the incorporation of radiolabelled iodide into cells that had phagocytosed bacteria. The present studies investigated the stoichiometry of these reactions and the subcellular localization and electrophoretic pattern of the cellular components that became iodinated. 1. The stoichiometry of the reactions are such that only a small proportion (less than 0.3%) of the total oxygen consumed is utilized for iodination. Iodination after stimulation with the soluble stimulus phorbol myristate acetate (PMA), which is not known to involve the azurophil granules and their contained myeloperoxidase, was comparable with that occurring after bacterial ingestion. 2. Analytical subcellular fractionation of cells that had phagocytosed bacteria localized about 25% of the radioactivity to the membranes, and most of the residual radioactivity distributed with the bacteria and dense granules. In cells stimulated with PMA, more of the radioactivity was associated with the membranes, but about half was still associated with the dense granules. 3. Autoradiographs after dodecyl sulphate/polyacrylamide-gel electrophoresis of cells stimulated with opsonized bacteria gave a similar distribution of iodinated components to that obtained with cells that had been stimulated with PMA or iodinated with Iodogen. These patterns of iodination were very different from those obtained when bacteria alone were iodinated with Iodogen or myeloperoxidase and H2O2. Preparations in which bacteria had been phagocytosed did not show evidence of iodination of bacterial proteins or coating opsonins. Thus positive evidence for the iodination of bacteria has not been produced, and the role of iodination in the microbicidal process of neutrophils remains to be established.

The association of FAD with the cytochrome b-245 of human neutrophils

A plasma membrane fraction prepared from human neutrophils had a fluorescence resembling that of a fluorescent flavoprotein, with emission maximum near 520nm and excitation maxima near 380 and 460nm. The fluorescence emission and excitation properties of Triton N-101-solubilized membrane fraction resembled those of FAD. FAD was present in the membranes at a concentration of 417pmol/mg of protein and cytochrome b(-245) at a concentration of 407pmol/mg of protein. In a 110-fold purified preparation of cytochrome b(-245) the ratio of FAD:cytochrome b was 1:1. Analytical gradient centrifugation of neutrophil homogenates shows a coincidence of two cytochrome b peaks and two peaks of fluorescence, corresponding with plasma membrane and specific granule fractions; most of the FAD was non-fluorescent and located in fractions lighter than the plasma membrane. Plasma membrane fractions prepared from neutrophils of patients suffering from the X-linked form of chronic granulomatous disease lacked cytochrome b and contained 194pmol of FAD/mg of protein; plasma membrane fractions prepared from neutrophils of patients with the autosomal recessive form of chronic granulomatous disease contained both cytochrome b(-245) and FAD in the normal range of concentrations in a ratio of 1:1. Phagocytic vesicles were prepared from normal neutrophils and found to contain FAD and cytochrome b in a ratio 2.22:1, suggesting that activation of neutrophils many involve the incorporation of an additional flavin into the membrane. Under anaerobic conditions in the presence of EDTA to act as an electron donor to a flavin, the cytochrome b(-245) of neutrophil membranes was partly (12%) photoreducible, an effect increased to 100% by the addition of FMN. The extent of reduction of cytochrome b in an anaerobic neutrophil homogenate containing NADH increased from 30% to 70% on illumination. We suggest that these results indicate a close association between FAD and cytochrome b(-245) and support a scheme for electron transport thus: [Formula: see text]

Development of cytochrome b and an active oxidase system in association with maturation of a human promyelocytic (HL-60) cell line

The human HL-60 myeloid leukaemia cell line developed, during maturational changes induced by dimethyl sulphoxide, an enhanced capacity for phorbol myristate acetate- stimulated oxidative activity and acquired a cytochrome b. Titration of the absorbance at 559 nm at potentials of-190 to -370 mV indicated that this cytochrome had a very low potential, differentiating it from mitochondrial and endoplasmic reticulum cytochromes and identifying it as the cytochrome b(-245) that has been recently found in other phagocytic cells. Subcellular fractionation studies of mature HL-60 cells showed that cytochrome b had a dual distribution within the cell. The lighter peak of activity was associated with the plasma membrane markers, adenylate cyclase and receptors for the N- formal-L-methionyl-L-leucyl-L-phenylalanine (f-Met-Leu-Phe) peptide. The denser components localized with the mitochondria but were distinct from mitochondrial cytochromes because whereas the activity of cytochrome c oxidase fell during HL-60 cell maturation, that of this cytochrome b was markedly increased. Concentrations of myeloperoxidase were unrelated to activity of the oxidase system and decreased as the cell matured. The increase in the concentrations of cytochrome b with cellular maturation parallelled the increase in the stimulated nonmitochondrial respiratory activity of these cells. The turnover of the hexose monophosphate shunt of immature cells was increased by the oxidising agents, methylene blue and tert-butylhydroperoxide, indicating that these immature cells have stimulated nonmitochondrial respiratory activity by maturing HL-60 cells is associated with, and is probably dependent upon, the acquisition by these cells of the cytochrome b(-245) oxidase system.

The action of cells from patients with chronic granulomatous disease on Staphylococcus aureus

Contrary to current opinion, neutrophil leucocytes from patients with the inherited immunodeficiency syndrome chronic granulomatous disease (CGD) killed 80% of ingested Staphylococcus aureus. Bacterial killing was not impaired by increasing the ratio of bacteria to cells from 1:1 to 10:1. The organisms that survived within the patients' cells did not themselves appear to constitute an unduly resistant subpopulation because they were killed when exposed to fresh cells, and no growth phase of a synchronous culture was found to be particularly resistant. The pH within the phagocytic vacuoles of CGD neutrophils and monocytes is abnormally low and methylamine, which has been shown to normalise this vacuolar pH, improved killing. Clumped bacteria appeared to be more resistant to killing than dispersed ones, suggesting that organisms near the centre of a clump might be protected from the toxicity of the compromised killing systems in cells of these patients.

The enzymic reduction and kinetics of oxidation of cytochrome b-245 of neutrophils

1. The absorption coefficient of human neutrophil plasma-membrane reduced-minus-oxidized cytochrome b-245 was determined [delta epsilon (mM; 559-540 nm) = 21.6 cm-1]. 2. Neutrophil polymorphonuclear leucocytes (neutrophils) were prepared from human, ox, horse and pig blood. In each case plasma-membrane fractions were found to contain low-potential cytochrome b. When membranes from horse neutrophils were incubated anaerobically with either NADH or NADPH the cytochrome b became reduced. Prior stimulation of the cells with phorbol myristate acetate did not increase the rate or extent of cytochrome b reduction in isolated membranes, but did increase both the rate and extent of reduction by NADPH in Triton-treated cells. 3. A cytochrome b was present also in the specific granule fraction of human neutrophils. Its Em (pH 7.0) was found to be -248 mV, very similar to that of the plasma-membrane cytochrome b. 4. The rate of oxidation of reduce cytochrome b-245 by air-saturated buffer, was determined by using stopped-flow techniques. In intact membranes t 1/2 for oxidation was 4.7 ms. This rate is sufficiently rapid to support the view that cytochrome b-245 is the oxidase in the respiratory burst of neutrophils. 5. Plasma-membrane cytochrome b of human neutrophils formed a complex with CO. At room temperature and 1 atm of CO approx. 40% of the cytochrome formed a complex; approx. 60% binding was measured at the increased concentration of dissolved CO achieved at 5 degrees C. The concentration of CO giving 50% binding was 1.18 mM.

Inhibition of lipid peroxidation by the iron-binding protein lactoferrin

Lactoferrin containing physiological amounts of iron is an inhibitor of lipid peroxidation induced by iron(III) salts and ascorbic acid. It might therefore help to protect neutrophils, inflammatory foci and secretions from metal-ion-dependent oxidative damage.

Indium-111 tagged leucocytes in the diagnosis of inflammatory bowel disease

The distribution of autologous leucocytes labelled with the gamma-ray emitting radioisotope indium-111 was studied in 25 patients with inflammatory bowel disease, 15 with Crohn's disease, and 10 with ulcerative colitis. In all instances the bowel lesion was identified. Radioactivity rapidly accumulated in the lesions over the first 2 h and then passed into the lumen of the bowel within the next 48 h, being redistributed from the liver and spleen. Normally, about 1% of the radioactivity passes into the stools in the 48 h after injection whereas approximately 20% of the administered radioactivity was found in the stools of the patients with inflammatory bowel disease. This noninvasive technique can show the extent of disease in patients too ill for conventional procedures. It can display abscesses and other lesions, and can be performed in outpatients.

Cytochrome b-245 of neutrophils is also present in human monocytes, macrophages and eosinophils

A cytochrome b with a midpoint oxidation-reduction potential of -245mV (cytochrome b-245) that is a major component of the microbicidal oxidase system of human neutrophil leucocytes has been identified in human eosinophils, monocytes and macrophages at concentrations similar to that found in human neutrophils. It was absent from a variety of other cells. This cytochrome is present in phagocytic leucocytes and probably plays an important part in the specialized activities of these cells.

The respiratory burst of phagocytic cells is associated with a rise in vacuolar pH

Neutrophil leukocytes are the body's major defence against bacteria, which they phagocytose and kill. It has been found that phagocytosis and killing are accompanied by a dramatic rise in non-mitochondrial respiration; and that the efficiency of killing is impaired in the absence of oxygen. It is also impaired in neutrophils from patients with chronic granulomatous disease (CGD), where the respiratory burst is absent. This has been difficult to reconcile with their normal content of granule proteins that kill bacteria in vitro. Indeed, CGD cells are essentially normal both morphologically and constitutionally except that they lack a functional very low potential cytochrome b (b-245), which is a component of the oxidase system responsible for the respiratory burst of normal cells. Activation of the oxidase is associated with the generation of various reduced oxygen species which have been widely thought to be responsible for the killing of phagocytosed microorganisms either directly, or by acting as substrates for myeloperoxidase-mediated halogenation. We report here, however, that a major consequence of the defective function of this oxidase in neutrophils and monocytes from CGD patients is an absence of the normal initial rise, and an unusually rapid and extensive fall in pH which is itself associated with the impairment of the killing and digestion of intracellular staphylococci.

Oxidation-reduction properties of the cytochrome b found in the plasma-membrane fraction of human neutrophils. A possible oxidase in the respiratory burst

The oxidation-reduction midpoint potential of the cytochrome b found in the plasma membrane of human neutrophils has been determined at pH 7.0 (Em,7.0) from measurements of absorption spectra at fixed potentials. In both unstimulated and phorbol myristate acetate-stimulated cells Em,7.0 was -245 mV. Changes in pH affected the Em of the cytochrome b, with a slope of approx. 25 mV/pH unit change. The Em,7.0 of the haem group(s) of the membrane-bound myeloperoxidase of human neutrophils was found to be +34 mV. The plasma membranes contained no detectable ubiquinone, and no iron-sulphur compounds were detected by e.p.r. spectroscopy at 5-20 K. No flavins were detected by e.p.r. spectroscopy. The cytochrome b-245 was not reduced by added NADH or NADPH. Dithionite-reduced cytochrome b-245 formed a complex with CO, supplied as a saturated solution, which was dissociated with 26 microseconds illumination from a xenon flash lamp, and the recombination with CO had a half-time of approx. 6 ms. Partly (80%) reduced cytochrome b-245 was oxidized by added air-saturated buffer with a half-time faster than 1 s at 20 degrees C, a resolution limited by mixing time. These results are compatible with cytochrome b-245 acting as an oxidase.

Elemental diets in treatment of acute Crohn's disease

Twenty-seven patients with 32 acute exacerbations of Crohn's disease were treated for four weeks with an elemental diet. At the end of treatment 29 of the exacerbations had remitted both clinically and biochemically. After six months six patients had relapsed. These findings suggest that the elemental diet is effective in treating acute Crohn's disease, but the reasons are not clear. The diet may be effective because it provides nutritional support, is hypoallergenic, acts as a medical bypass from the affected area, or alters bowel flora. The patient's general wellbeing is improved by the supply of adequate energy and essential foodstuffs in a form easily available without further digestion and given in a safe, simple, non-toxic way.

Kinetics of fusion of the cytoplasmic granules with phagocytic vacuoles in human polymorphonuclear leukocytes. Biochemical and morphological studies

This study on human neutrophils was conducted to measure the kinetics of degranulation of the different cytoplasmic granules into phagocytic vacuoles, and to relate the timing of these events to the burst of respiration that accompanies phagocytosis by these cells. Purified neutrophils were incubated with latex particles opsonized with human immunoglobulin (Ig)G, and phagocytosis was stopped at timed intervals. The cells were examined by electron microscopy to document the sequence of degranulation of the cytoplasmic granules. The azurophil granules and lyosomes were identified by histochemical staining for peroxidase and acid phosphatase, respectively. Phagocytic vacuoles were separated from cell homogenates by floatation on sucrose gradients and assayed for contained lactoferrin, myeloperoxidase, and acid hydrolases. The conclusions drawn from the biochemical and morphological studies were in agreement and indicated: particle uptake and vacuole closure can be completed within 20 s; both the specific and azurophil granules fuse with the phagocytic vacuole much earlier than is generally appreciated, with half-saturation times of 39 s (99% confidence limits, 15-72); oxygen consumption has kinetics similar to those of the fusion of these granules with the phagosome; degranulation of the acid hydrolases beta-glucuronidase, N-acetyl-beta-glucosaminidase (biochemical assays), and acid phosphatase (biochemical assay and electron microscopic cytochemistry) have kinetics of degranulation that are similar to each other but totally different from and much slower than that of myeloperoxidase with half-saturation times of between 354 and 682 s (99% confidence limits, 246-883). This suggests that the acid hydrolases are not co-located with myeloperoxidase in the azurophil granule but are contained in distinct lysosomes, or "tertiary granules".

A rapid single centrifugation step method for the separation of erythrocytes, granulocytes and mononuclear cells on continuous density gradients of Percoll

A simple rapid method of separating mononuclear leucocytes, granulocytes and erythrocytes on continuous Percoll density gradients has been developed. The Percoll is mixed with increasing amounts of the blood, which forms the light phase of the gradient. Centrifugation at 400 X g for 30 min results in almost complete separation of the 3 groups of cells with high recoveries and degrees of purity. Blood samples from 3 patients with chronic granulomatous disease were separated with this technique and the pattern of cell separation was found to be different from normal.

Halothane does not inhibit human neutrophil function in vitro

Various indices of function of neutrophils from normal healthy volunteers have been examined after in vitro exposure to halothane. Random free movement on glass was unaffected, but random migration through millipore filters was slightly increased. There was no significant change in migration in response to casein chemotaxis. Phagocytosis, degranulation and the enhanced non-mitochondrial respiration associated with phagocytosis were unaffected. Electron-microscopic appearance at 30 s after exposure to latex particles was normal in all respects.

The subcellular distribution and some properties of the cytochrome b component of the microbicidal oxidase system of human neutrophils

A novel cytochrome b has recently been described in human neutrophils. The subcellular distribution of this cytochrome was investigated by analytical fractionation on continuous sucrose gradients and it was found to have a dual localization, the major component having a similar distribution to the plasma-membrane marker [3H]concanavalin A, and a denser peak located with the specific granules. The two components were separated on discontinuous gradients and studied independently.

Tracing the fate of oxygen consumed during phagocytosis by human neutrophils with 15O2

1. The metabolism of oxygen by phagocytosing neutrophils was traced by using 15O2. 2. The isotope did not exchange with the incubation medium or cells to an appreciable extent and unmetabolized oxygen was readily eluted by gassing the cell suspension. 3. The polarographic measurements of oxygen consumption closely paralleled the recovery of metabolized 15O2. 4. Almost all the metabolized 15O2 was converted into water, both in the presence and absence of KCN, supporting the concept that the oxygen consumed by neutrophils is converted into H2O2. It is unlikely that an appreciable proportion of this oxygen is incorporated into the organic composition of the cell or of the ingested micro-organism.

Absence of a newly described cytochrome b from neutrophils of patients with chronic granulomatous disease

A unique cytochrome b which becomes incorporated into phagocytic vacuoles has been described in human neutrophils. This cytochrome b appears to be situated in the plasma membrane of these cells, and acts as a component of the microbicidal oxidase system. Absence or gross abnormality of this cytochrome b was demonstrated in all four patients with chronic granulomatous disease who were investigated, and reduced concentrations in two mothers known to be carriers of the disease.

Oxygen consumption by stimulated human neutrophils

Oxygen consumption by stimulated human neutrophils has been studied. An initial lag after stimulation of about 20 s is followed by a linear phase of oxygen consumption which lasts about 60 s and then declines exponentially. The duration of the respiratory burst is thus much shorter than has been generally recognized. The cessation of the linear phase of oxygen consumption occurs at a constant time after stimulation, is not due to depletion of the substrate of the oxidase enzyme (since linear oxygen consumption can be re-initiated), and is due to termination or saturation of particle uptake. The curtailment of oxygen consumption probably marks the end of the oxygen-dependent microbial role of the phagocytic vacuole, preparing it for the secondary and independent function of digestion. A novel cytochrome b becomes associated with the phagosomes and probably forms a component of a complex electron-transport chain. Superoxide may be an intermediate in this system, but it is unlikely to be released free from the cell or to form the final product of the system.

Analytical subcellular fractionation of neutrophils from patients with chronic granulomatous disease. Demonstration of the enzyme defect in four cases

Analytical subcellular fractionation studies were performed on neutrophils from five patients, including two females, with chronic granulomatous disease. The density distribution and marker enzyme activities of the principal subcellular organelles in unstimulated cells were similar to those in unstimulated neutrophils from control subjects. NADH dependent reduction of nitroblue tetrazolium was measured in four of the patients including one female. In homogenates of whole cells the specific activity of this enzyme expressed as milliUnits/mg protein was lower in the patients than in the controls, but the difference was not statistically significant. There was however a highly significant difference between the specific activities of this enzyme in the plasma membrane fractions isolated from neutrophils of the four patients and the three controls. These findings suggest that the primary microbicidal oxidase of neutrophils, defective function of which manifests as the syndrome of chronic granulomatous disease, is a plasma membrane NADH oxidoreductase.

Indium-111-labeled cellular blood components: mechanism of labeling and intracellular location in human neutrophils

Human neutrophils were labeled with In-111 oxine by incubation at room temperature, and the fate of the oxine and the intracellular location of the In-111 were determined. Neutral (1:3) In-111 oxine complex diffuses rapidly across the cell membrane and then dissociates. Some of the oxine leaves the cell and the In-111 binds intracellularly. After short periods of incubation the label is distributed mostly to four soluble components, a small proportion of which had a distribution similar to that of specific and azurophil granules. After longer incubation periods there was relatively less radioactivity with the soluble components and probably more attached to the particulate material. A small peak of radioactivity also appeared in the region of DNA distribution, but no confirmation could be obtained for the association of the In-111 radioactivity with DNA.

Indium-111-labeled autologous leukocytes in man

Autologous leukocytes have been isolated, labeled with indium-111, and administered to 15 patients suspected of inflammatory disease. The stability of the label has been demonstrated and the in vivo kinetics and distribution of the labeled cells studied. The distribution is influenced by the type and viability of the cells separated by three different techniques. Generally, there was initial accumulation of radioactivity in the lungs; approximately half of this cleared in 15 min and the remainder slowly. Twenty-five to 50 percent of the radioactivity subsequently distributed in the spleen, liver, and bone marrow, and these did not show significant change with time up to 48 hr post injection. The In-111 radioactivity administered as labeled leukocytes free from erythrocytes cleared from the circulating blood with a half-time of 7.5 hr. In three of 15 patients, the suspicion of inflammatory disease could not be confirmed, and in these a normal distribution of radioactivity was observed. In the remaining 12 patients, focal accumulation of radioactivity was detectable within 4 to 24 hr after administration, and subsequent confirmation of sepsis was obtained. From three such patients, samples of abscesses were recovered which showed markedly higher radioactivity than that in the same weight of blood.

Levamisole in the treatment of Crohn's disease

In 8 patients with active uncomplicated Crohn's disease who were not receiving any specific therapy, a clinical remission was induced with an elemental diet, and then an attempt was made to maintain this remission with levamisole. This regimen resulted in excellent control of the disease. A drug-induced arthritis developed in two patients and resolved spontaneously. There were no other significant side-effects.

Painless ascites in systemic lupus erythematosus

Images

Analytical subcellular fractionation of human granulocytes with special reference to the localization of enzymes involved in microbicidal mechanisms

1. Granulocytes were isolated from 40–400 ml of human blood, disrupted and subjected to analytical subcellular fractionation by centrifugation on sucrose density gradients.

2. The principal subcellular organelles, characterized by their respective marker enzymes, were resolved on the density gradients. The subcellular localization of hitherto unassigned enzymes was determined by comparison with the marker enzymes.

3. NAD(P)H-dependent reduction of nitroblue tetrazolium at high nucleotide concentration (2·5 mmol/l) and NAD(P)H/cytochrome c reduction has a complex distribution with activity in the plasma membrane, mitochondria and cytosol fractions.

4. At a lower, physiological concentration of pyridine nucleotides (25 μmol/l), NADH-dependent nitroblue tetrazolium reduction was confined to the plasma membrane whereas NADPH dependent-reduction of the dye was undetectable. NAD(P)H/nitroblue tetrazolium reductase activity was partially inhibited by superoxide dismutase.

5. NADPH and NADH oxidase activities, measured by the production of oxidized nucleotide, were localized with the azurophil granules.

6. Superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase were localized predominantly to the cytosol.

7. Neutral α-glucosidase and γ-glutamyl transpeptidase showed a bimodal distribution with localizations to both endoplasmic reticulum and specific granule components.

8. It is suggested that the plasma membrane, and thus the wall of phagocyte vacuoles, contains a free radical generating NADH-dependent enzyme which plays a primary bactericidal role. The cytosol contains mechanisms which detoxify hydrogen peroxide, superoxide and free radicals and protect the granulocyte from these compounds.

Indium-111-labelled leucocytes for localisation of abscesses

Leucocytes from eight patients who were thought to have an abscess were labelled with indium-111 and reintroduced into the circulation. The distribution of radioactivity was followed by whole-body scanning and imaging with a gamma camera. Focal accumulation of radioactivity were observed in the lesion in the three patients with abscesses, in the lungs of a boy with bacterial endocarditis, in the knee of a woman with rheumatoid arthritis, and at the site of intramuscular injections in another patient. The use of radiolabelled cells for the detection of focal pathological processes would seem to be an important addition to conventional diagnostic methods.

Tissue and hepatic subcellular distribution of liposomes containing bleomycin after intravenous administration to patients with neoplasms

1. Liposomes containing 111In-labelled bleomycin were injected intravenously into two patients. One patient had a hepatoma and the other had secondary adenocarcinomatous deposits in the liver. 2. The tissue distribution of 111In was determined by whole-body scanning and by measurement of the radioactivity in organs at autopsy. 3. Scans in vivo and post-mortem measurement of radioactivity indicated that liposomes accumulate predominantly in the liver, but that there is no selective uptake of liposomes by the malignant tissue. 4. The subcellular distribution of radioactivity in the liver was measured 90 min after injection by fractionation of percutaneous liver biopsies on sucrose density gradients. 5. Radioactivity within the liver was concentrated in lysosomes. 6. Electron microscopy of tissue obtained before the administration of liposomes revealed particles morphologically indistinguishable from liposomes in hepatoma cells and hepatocytes.

Neutrophil dysfunction in Crohn's disease

The migration of neutrophils into skin windows has been examined in patients with Crohn's disease and rheumatoid arthritis and compared with normal. Leucocyte migration was significantly lower in patients with Crohn's disease than in others. This abnormality of neutrophil function in Crohn's disease appears to be secondary to a defective acute inflammatory response as the neutrophils themselves were found to behave normally on in-vitro testing. A weak acute inflammatory response to particulate or antigenic material in the bowel wall could result in the chronic inflammation observed in this condition.

Characterisation of the enzyme defect in chronic granulomatous disease

Strikingly reduced activity of an enzyme, normally located in the plasma membrane of human neutrophils, has been demonstrated in a male patient with chronic granulomatous disease (C.G.D.). The subcellular distribution of N.A.D.H.-dependent reduction of nitroblue tetrazolium (N.B.T.) was determined in neutrophils because reduction of this dye by these patients is grossly impaired. Assayed at high concentrations of N.A.D.H. (1 mmol/1), N.B.T. is reduced by enzymes in the cytosol and mitochondria in addition to the plasma membrane by both normal and C.G.D. cells--properties which previously obscured the identity and location of this enzyme. At a more physiological concentration of N.A.D.H. (25 mumol/1), reduction of the dye by the plasma membrane, the principal site of N.B.T. reduction by normal neutrophils, was absent in the patient with C.G.D. It is suggested that absence or imperfect function of this reductase enzyme is the primary lesion in this disease.

The nylon column dye test: a possible screening test of phagocyte function

1. A simple quantitative test has been developed to investigate phagocyte function. 2. This test is performed by the addition of Nitroblue Tetrazolium to whole blood, followed by the isolation of leucocytes on a column of nylon wool. Dye reduction by phagocytes is apparent as a blue coloration of the column due to the formation of formazan. The formazan can be extracted from the column and measured spectrophotometrically. 3. The formation of formazan was found to be directly related to the number of phagocytes in blood. 4. Two patients with chronic granulomatous disease gave abnormal results, suggesting that the test procedure may be of value as a screening procedure for this disease.

Importance of the site of endoscopic gastric biopsy in ulcerating lesions of the stomach

Twenty freshly resected stomach specimens, each containing an ulcerated carcinoma, were studied in an attempt to determine the best site for gastric biopsy. Using endoscopic biopsy forceps multiple biopsies were obtained from various sites around the ulcer. Carcinoma was detected with similar frequency in biopsies from the slough and from the rim of the ulcer. The positive biopsy rate was increased to 95% when the results from the rim and the slough were combined. It is suggested that the diagnostic accuracy of endoscopic gastric biopsy can be improved by taking biopsies from both the rim and the slough of an ulcer.

Liposomes as vehicles for the local release of drugs

1. The rat testicle was used in studying the release of radio-labelled compounds from locally injected liposomes of various sizes, charge and lipid composition. 2. Large unsonicated liposomes markedly delayed the release of entrapped 125I-labelled albumin. Delay was due to liposomal entrapment rather than the presence of lipid per se and it was greater with neutral than charged liposomes. The albumin left the testis after release from, and not in association with, liposomal lipid. 3. Large unsonicated liposomes also delayed the release of entrapped actinomycin D and 5-fluourouracil. The former retained its cytotoxic activity and resulted in focal, dose-dependent tissue necrosis. 4. Small sonicated liposomes did not delay the release of entrapped 125I-labelled albumin, and enhanced release of actinomycin D, producing high concentration of these compounds, which were released in association with liposomal lipid, in draining lymph nodes.