Practices and perspectives of primary care physicians in Japan and the United States about diagnosing dementia: a qualitative study

Background

While dementia is a common problem in Japan and the US, primary care physicians' practices and perspectives about diagnosing dementia in these different healthcare systems are unknown.

Methods

Qualitative research was conducted in an ethnographic tradition using semi-structured interviews and thematic analysis in primary care settings across Japan and in the Midwest State of Michigan, US. Participants were a total of 48 primary care physicians, 24 each from Japan and the US participated. Both groups contained a mixture of geographic areas (rural/urban), gender, age, and years of experience as primary care physicians.

Results

Participants in Japan and the US voiced similar practices for making the diagnosis of dementia and held similar views about the desired benefits of diagnosing dementia. Differences were found in attitudes about the appropriate timing of formally diagnosing dementia. Japanese physicians tended to make a formal diagnosis when problems that would benefit from long-term care services emerged for family members. US physicians were more proactive in diagnosing dementia in the early stages by screening for dementia in health check-ups and promoting advance directives when the patients were still capable of decision-making. Views about appropriate timing of diagnostic testing for dementia in the two systems reflect what medical or nursing care services physicians can use to support dementia patients and caregivers.

Conclusions

Benefits of making the diagnosis included the need to activate the long-term care services in Japan and for early intervention and authoring advance directives in the US. Testing to establish an early diagnosis of dementia by primary care physicians only partly relates to testing and treatment options available. Benefits of making the diagnosis included the need to activate the long-term care services in Japan and for early intervention and authoring advance directives in the US.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02457-7.

Secretion of toxic oxygen products by macrophages: regulatory cytokines and their effects on the oxidase

We are attempting to identify cytokines that regulate macrophage secretion of reactive oxygen intermediates (ROI) and to analyse the biochemical basis of their effects. In both humans and mice, interferon-gamma (IFN-gamma) appears to be the chief factor secreted by clonally unselected lymphocytes that enhances macrophage oxidative metabolism and antiprotozoal activity. In vivo administration of recombinant IFN-gamma enhances the ROI secretory capacity of monocytes in humans, and the secretion of ROI and killing of protozoa by peritoneal macrophages in mice. A protein secreted by murine tumours and certain non-malignant cells exerts opposing effects. This macrophage deactivation factor (MDF) both blocks the induction of activation by IFN-gamma and reverses pre-existent activation. MDF action is non-toxic and selective, suppressing the secretion of ROI, killing of intracellular protozoa, and expression of Ia antigen, without inhibiting secretion of several other products, or synthesis of protein, ingestion of particles or adherence to culture vessels. The suppressive effect of MDF is reversed over several days after its removal. This reversal is hastened by IFN-gamma. Profound suppression of oxidative metabolism accompanies the differentiation of murine monocytes into Kupffer cells. The capacity of Kupffer cells to secrete ROI and kill intracellular protozoa remains deficient even after exposure to IFN-gamma. Thus, four states of macrophage activation can provisionally be discerned: the transition of mouse peritoneal macrophages from the non-activated to the activated state is accompanied by a ninefold increase in affinity of the superoxide-producing enzyme for NADPH, without a marked increase in cellular Vmax or content of cytochrome b559. The MDF-induced transition of mouse peritoneal macrophages from the activated to the deactivated state is accompanied by both an increase in Km and a decrease in apparent V max of the oxidase. There are no changes in the phorbol myristate acetate receptor number or affinity, glucose transport, NADPH levels, cytochrome b559 content, catalase (EC 1.11.1.6) GSH, GSH peroxidase (EC 1.11.1.9), GSH reductase (EC 1.6.4.2) or myeloperoxidase, consistent with the suppressed ROI secretory capacity and antiprotozoal activity of these cells. The Kupffer cell, whose non-responsiveness to IFN-gamma may mark it as inactivated, appears to lack detectable NADPH oxidase activity, despite the probable presence of cytochrome b559, and in this regard differs from both non-activated and deactivated macrophages.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of a p67(phox) homolog in Caco-2 cells giving O(2)(-)-reconstituting ability to cytochrome b(558) together with recombinant p47(phox)

Human normal and transformed (Caco-2) colon tissues as well as guinea pig gastric mucosal cells express Nox1, which is a homolog of the phagocyte NADPH oxidase subunit, gp91(phox) of membrane-bound cytochrome b(558). It was reported that Nox1-transfection to NIH 3T3 cells could provide O(2)(-)-generating ability, independently of regulatory cytosolic factors (Rac2, p67(phox), and p47(phox)) that are obligatory in the phagocyte oxidase system. Here, we detected and sequenced a p67(phox) homolog in Caco-2 almost identical to the neutrophil sequence, except for three nucleotide substitutions, two of which changed lysines 181 and 328 to arginines. Investigation of its ability to support O(2)(-)-generation in cell-free reconstitution experiments combining with neutrophil cytochrome b(558) showed O(2)(-)-generation, provided that recombinant p47(phox) was added. This result demonstrates that the intrinsic p67(phox) homolog of Caco-2 was able to function as a phagocyte p67(phox) for cytochrome b(558). The requirement of p47(phox) addition suggested that this component was absent in Caco-2 cells. Caco-2 membranes, used as a source of Nox1 in place of cytochrome b(558), did not show significant O(2)(-)-generation, which was mainly explained by their very little Nox1 expression.

Evaluation of the process for superoxide production by NADPH oxidase in human neutrophils: evidence for cytoplasmic origin of superoxide

We present an up-to-date insight into the function of NADPH oxidase in human neutrophils, the signalling pathways involved in activation of this enzyme and the process of association of its components with the cytoskeleton. We also discuss the functional implications of morphological studies revealing localization of the sites of NADPH oxidase activity. An original model of the process of superoxide (O2*-) production in human neutrophils is shown. Organization of NADPH oxidase is associated with several components. Upon stimulation, tri-phox cytosolic components of NADPH oxidase (p40-phox, p47-phox and p67-phox) bind to actin filaments. This process involves other actin-binding proteins, such as cofilin and coronin. Activated protein kinase C, translocated from the plasma membrane, phosphorylates cytosolic components at a scaffold of cytoskeleton. Subsequently, p40-phox, responsible for maintaining the resting state of NADPH oxidase, is separated from other two cytosolic phox proteins following an attachment of the active form of small GTP-binding protein Rac to p67-phox. Cytosolic duo-phox proteins (p47-phox and p67-phox) conjugate with membrane components (gp91-phox, p22-phox and Rapla) of NADPH oxidase residing within membranes of intracellular compartments. This chain of events triggers production of O2*-. Then, oxidant-producing intracellular compartments associate with the plasma membrane. Eventually, intracellularly produced O2*- is released to the extracellular environment through the orifice formed by fusion of oxidant-producing compartments with the plasma membrane. Intracellular movement of the oxidant-producing compartments may be regulated by myosin light chain kinase. The review emphasizes that functional assembly of NADPH oxidase and, therefore, generation of O2*- is accomplished essentially within the intracellular compartments. Upon neutrophil stimulation, intracellularly generated O2*- is transported to the plasma membrane to be released and to ensure host defense against infection.

Relationships of p40(phox) with p67(phox) in the activation and expression of the human respiratory burst NADPH oxidase

p40(phox) of the phagocyte NADPH oxidase forms a complex with p67(phox) in cytosol, and coincidentally decreases in patients who lack p67(phox). Here we investigated the mode of translocation of p40(phox) to the membrane, its cytoskeletal localization on activation of the NADPH oxidase, and the dependency of its expression relative to that of p67(phox). When human polymorphonuclear leukocytes (PMNs) were stimulated with phorbol myristate acetate (PMA), p40(phox) was translocated to the membrane along with p67(phox), and not was released into the cytosol. Studies with resting PMNs using Triton X-100 revealed the exclusive localization of p67(phox) in the cytoskeletal fraction. Unexpectedly, however, about half of p40(phox), which is deemed to be fully associated with p67(phox), was recovered in the non-cytoskeletal fraction. Unlike p47(phox), the association of p40(phox) with cytoskeleton was not induced by the PMA-stimulation. These results indicate not only that p40(phox) associates with cytoskeleton via a molecule of p67(phox), but also that there are distinct states of p40(phox) that can be manipulated with Triton X-100. Lastly, Western-blot analysis of hematopoietic cells revealed no correlation between p40(phox) and p67(phox) in their protein expressions during cell differentiation, and also that p40(phox) can be stably present alone in cells, unless in the case of mature PMNs. In this regard, definitive proof was obtained with Epstein-Barr virus-transformed B cells of a p67(phox)-deficient patient, in which p40(phox) was normally expressed.

Direct interaction of actin with p47(phox) of neutrophil NADPH oxidase

The cell-free activation of human neutrophil NADPH oxidase is enhanced by actin, and actin filaments formed during activation are suggested to stabilize the oxidase. In an attempt to elucidate the mechanism, we examined the protein-protein interactions between actin and cytosolic components of the oxidase. Far-Western blotting using recombinant phox proteins showed that both alpha- and beta-actin interacted with p47(phox) and rac1, and weakly with rac2. A deletion mutant of p47(phox) proved that its C-terminal region was essential for the interaction. The dissociation constant (K(d)) for interaction between actin and p47(phox) was estimated to be 0.45 microM by surface plasmon resonance, and that between actin and rac1 or rac2 was 1.7 or 4.6 microM, respectively. Far-Western blotting using cytosol as a target showed an interaction between actin and endogenous p47(phox) and rac proteins. These results suggest that actin can directly interact with p47(phox) and possibly with rac in the cells.

Suppressive effect of rebamipide, an antiulcer agent, against activation of human neutrophils exposed to formyl-methionyl-leucyl-phenylalanine

Rebamipide, an antiulcer agent, has been shown to be able to prevent gastric mucosal injury resulting in part from activation of neutrophils. The mechanism of its suppressive action, however, remains to be established. The present study aimed to determine the effect of rebamipide on activation of isolated human neutrophils and to identify the signal transduction pathway involved in its regulation. In unstimulated cells, alkaline phosphatase activity was found residing in short rod-shaped intracellular granules. Upon stimulation with a chemotactic peptide formyl-methionyl-leucyl-phenylalanine, the granules fused to form elongated tubular structures and spherical vacuoles. Rebamipide inhibited reorganization of alkaline phosphatase-containing granules along with upregulation of alkaline phosphatase activity and CD16, a marker of the granules. It also suppressed chemotaxis, an increase in intracellular calcium ion concentration, and NADPH oxidase activation in cells stimulated with formyl-methionyl-leucyl-phenylalanine. In contrast, the drug showed no inhibitory action toward upregulation of alkaline phosphatase activity and CD16, and activation of NADPH oxidase in cells stimulated with phorbol myristate acetate, an activator of protein kinase C. These findings demonstrate that rebamipide exerts a broad spectrum of suppressive actions toward biological functions of human neutrophils stimulated with formyl-methionyl-leucyl-phenylalanine, but not with phorbol myristate acetate, and suggest that the upstream point of protein kinase C is the signal transduction pathway involved in its regulation.

Fungal gliotoxin targets the onset of superoxide-generating NADPH oxidase of human neutrophils

Gliotoxin from Aspergillus, bearing a S&bond;S bond in its structure, prevented the onset of O(-)(2) generation by the human neutrophil NADPH oxidase in response to phorbol myristate acetate (PMA). Gliotoxin affected the activation process harder than the activated oxidase, as shown by its stronger inhibition when added to neutrophils prior to, than post-PMA at maximum enzyme turnover. Decreased O(-)(2) generation persisted even if cells treated with gliotoxin were subsequently washed, with half-inhibition concentrations (IC(50)) of 5.3, and 3.5 microM for treatments of 15 and 30 min, respectively. In addition, gliotoxin made neutrophils reduce cytochrome c regardless of absence of PMA, through its reaction with intracellular reductants in an oxygen-dependent process, named redox cycling. Thus, we next tested whether preincubation of neutrophils with gliotoxin under hypoxic conditions would relieve the inhibition of NADPH oxidase. Instead, this prevention of redox cycling significantly favored damage to the NADPH oxidase with an IC(50) of 0.009 microM. Moreover, conversion of gliotoxin to its dithiol derivative by addition of reduced dithiothreitol during incubation protected cells from losing oxidase activity. These findings support that the disulfide form of gliotoxin targets NADPH oxidase activation.

Helicobacter pylori lipopolysaccharide enhances the expression of NADPH oxidase components in cultured guinea pig gastric mucosal cells

Recently, we showed that cultured guinea pig gastric pit cells possess a phagocyte NADPH oxidase-like activity, which was up-regulated by Helicobacter pylori lipopolysaccharide. We demonstrate here that these cells express all of the phagocyte NADPH oxidase components (gp91-, p22-, p67-, p47-, and p40-phoxes). Treatment with lipopolysaccharide increased the expression of gp91-, p22-, and p67-phoxes, but not that of p47- and p40-phoxes. Intriguingly, the p67-phox expression consistently correlated with up-regulation of superoxide anion-producing ability. Thus, the gastric pit cell NADPH oxidase may play an important role in regulation of the inflammatory response associated with H. pylori infection.

Accumulation of human T lymphotropic virus type I-infected T cells in the salivary glands of patients with human T lymphotropic virus type I-associated Sjögren's syndrome

OBJECTIVE

To clarify the involvement of human T lymphotropic virus type I (HTLV-I) in the pathogenesis of Sjogren's syndrome (SS).

METHODS

In HTLV-I-seropositive patients with SS, HTLV-I proviral DNA in the labial salivary glands (SG) was detected by polymerase chain reaction (PCR) amplification of the extracted cellular DNA, and the localization in the SG was examined by in situ PCR hybridization.

RESULTS

The cellular DNA extracted from the SG contained full HTLV-I proviral DNA, which was present in the nucleus of the infiltrating T cells, but not in either the SG epithelial cells or the acinar cells. Furthermore, the viral loads in the SG were approximately 8 times to 9 x 10(3) times higher than those in the peripheral blood mononuclear cells.

CONCLUSION

Accumulation of HTLV-I-infected T cells in the SG suggests that HTLV-I likely causes the self-reactive T cells to proliferate, which, as a result, induces SS.

Mutation at histidine 338 of gp91(phox) depletes FAD and affects expression of cytochrome b558 of the human NADPH oxidase

Defective NADPH oxidase components prevent superoxide (O-2) generation, causing chronic granulomatous disease (CGD). X-linked CGD patients have mutations in the gene encoding the gp91(phox) subunit of cytochrome b558 and usually lack gp91(phox) protein completely (X91(0)). gp91(phox) is considered to be a flavocytochrome that contains binding sites for NADPH, FAD, as well as heme. We here report a rare X-linked CGD patient whose neutrophils entirely failed to produce O-2, but presented a diminished expression of gp91(phox) containing about one-third of the heme present in normal individuals by Soret absorption. Translocation of cytosolic factors p67(phox) and p47(phox) was normal. However, the FAD content in his neutrophil membranes was as low as that of X91(0) patients, suggesting complete depletion of FAD in his gp91(phox). This was in agreement with the finding that a single base substitution (C1024 to T) changed His-338 to Tyr in gp91(phox) in a predicted FAD-binding domain of the flavocytochrome model. The loss of FAD could not be corrected even after addition of reagent FAD or a FAD-rich dehydrogenase fraction isolated from normal neutrophils to the patient's membranes, in a reconstitution in vitro with normal cytosol. These results indicate that His-338 is a very critical residue for FAD incorporation into the NADPH oxidase system. This is the first such mutation found in CGD.

[Improvement of respiratory burst by individual neutrophils from a patient with chronic granulomatous disease, type X91- under treatment by granulocyte colony-stimulating factor for multiple liver abscess]

A 20-year-old male with chronic granulomatous disease (CGD) was admitted with multiple liver abscesses. He had already been diagnosed as CGD, type X91-, when he was 10 years old. He was successfully treated with antibiotics and granulocyte colony-stimulating factor (G-CSF) combined with continuous drainage of abscess. Employing flow cytometry, respiratory burst by individual neutrophils was measured using 2', 7'-dichlorofluorescein. The fluorescence intensity in all individual neutrophils from the patient under G-CSF treatment was higher than the one without G-CSF. G-CSF can be one of effective therapies for infection in some patients with CGD such as X91-.

Involvement of p40phox in activation of phagocyte NADPH oxidase through association of its carboxyl-terminal, but not its amino-terminal, with p67phox

Phagocyte NADPH oxidase, dormant in resting cells, is activated upon cell stimulation to produce superoxide anion, a precursor of microbicidal oxidants. Active NADPH oxidase is found on the membrane as an enzyme complex, composed of membrane-integrated cytochrome b558 (gp91phox and p22phox subunits) and two cytosolic factors (p47phox and p67phox), each of the latter containing two src homology 3 (SH3) domains. Recently, we radioactively identified a third cytosolic factor, p40phox, as a molecule that associates with p67phox in human neutrophils. Although it has been found that this p40phox protein is defective in patients with chronic granulomatous disease (CGD) who lack p67phox, evidence to functionally relate it to the NADPH oxidase system has hitherto been lacking. In this study, we raised separate antibodies against both the COOH- and NH2-terminal polypeptides of p40phox as well as against the COOH-terminal polypeptide of p67phox to examine the mode of interaction between p40phox and p67phox in a complex. The antibody against the COOH terminus of p67phox was able to communoprecipitate p40phox in conjunction with p67phox itself as was expected. Very interestingly, however, the antibody against the COOH terminus of p40phox completely dissociated the p67phox molecule from the p40phox-p67phox complex unit without any detectable coimmunoprecipitation of p67phox, despite their tight association, whereas that against the NH2 terminus of p40phox had absolutely no dissociation effect. Similar results were found regarding their effects on the O2-generating ability of cytosol in a cell-free activation system, i.e., inhibition was noted with the COOH terminus antibody but not with that for the NH2 terminus of p40phox. However, this dissociation did not affect the translocation of the cytosolic components including p47phox to the membrane. Once the NADPH oxidase was activated, the antibody for the COOH terminus did not show any inhibitory effect on catalysis by the activated enzyme. The stimulators of NADPH oxidase, MA and SDS, did not dissociate the p40phox-p67phox complex. These results provide the first demonstration that p40phox is practically involved in the activation of NADPH oxidase through the association of its COOH-terminal, but not its NH2-terminal, with p67phox.

A novel cytosolic component, p40phox, of respiratory burst oxidase associates with p67phox and is absent in patients with chronic granulomatous disease who lack p67phox

Cytosolic components of human neutrophils, p47phox and p67phox, deficiencies of which lead to chronic granulomatous disease (CGD), potentiate respiratory burst oxidase translocating from cytosol to membrane upon cell stimulation. In this report we describe a novel cytosolic component, p40phox, which consistently behaves with p67phox through immunoprecipitation and column works, and is missing in patients with CGD who lack p67phox. Although actin has been reported to be involved in O2- generation, the p40phox profile did not correspond to that of actin. The tight association between p40phox and p67phox was not affected by treatment with a mixture of deoxycholate and Nonidet P-40, until subjected to SDS-PAGE. Addition of recombinant p67phox to cytosol did not produce any additional p40phox in the immunoprecipitate, unlike the additive increment in the band of p67phox. These results suggest that p40phox forms a complex with p67phox in a molar ratio of 1:1, without any free p40phox in the cytosol.

Activation of respiratory burst oxidase is accompanied by desensitization of p47phox in nucleoside-triphosphate binding along with its translocation to cell membrane

A cytosolic component of human neutrophils, p47phox, potentiates respiratory burst oxidase translocating from cytosol to membrane upon cell stimulation. In this study, the nucleotide-binding ability of p47phox was examined using [32P]GTP dialdehyde (oGTP), [32P]oATP, and [32P]oNADPH. p47phox showed affinities for both oGTP and oATP that were 14 times higher than that for oNADPH, suggesting that it is a nucleoside triphosphate (NTP)-binding protein rather than an NADPH-binding protein. Binding analysis of p47phox using either [32P]oGTP or [32P]oATP revealed an apparent binding constant for each individual NTP analogue and the same maximum binding value, which suggests that both NTPs share a common specific binding site. Stimulation of neutrophils with phorbol myristate acetate (PMA) resulted in enhancement of the oxidase activity to generate O2- anion and was accompanied by substantial translocation of p47phox to membrane. However, p47phox derived from the stimulated cell membrane had lost its NTP-binding ability, unlike that from the resting cytosol. These results suggest that the binding of NTP to p47phox may be involved in the process that activates the oxidase and is desensitized in translocated p47phox.

NADPH-binding component of the respiratory burst oxidase system: studies using neutrophil membranes from patients with chronic granulomatous disease lacking the beta-subunit of cytochrome b558

The NADPH-binding site of the respiratory burst oxidase system of neutrophils has been proposed to be either at a cytosolic component or at the beta-subunit of cytochrome b558. In this study, affinity labeling of resting and stimulated membranes, the latter having been assembled by all of the oxidase components from both membrane and cytosol, was carried out using [32P]NADPH dialdehyde (oNADPH). Stimulation of human neutrophils with PMA greatly increased O2(-)-generating activity and caused considerable translocation of the cytosolic components p47phox and p67phox. Nevertheless, PMA stimulation did not produce a labeled band which included positions at 47, 67, and approximately 32 kD. The most intense band reflected a molecular mass of 84 kD regardless of the state of activation, but a labeled band was never found near the beta-subunit (91 kD) of cytochrome b558. This 84-kD protein was further confirmed in neutrophils of 14 patients with gp91phox-deficient X-linked chronic granulomatous disease. These results indicate that the NADPH-binding component is not recruited from the cytosol, and also, that a membranous redox component besides cytochrome b558 must be involved in the NADPH oxidase system.

Nucleoside-triphosphate binding of the two cytosolic components of the respiratory burst oxidase system: evidence for its inhibition by the 2',3'-dialdehyde derivative of NADPH and desensitization in their translocated states

Affinity labeling of the two cytosolic components of the respiratory burst oxidase system, p49-phox and p63-phox, from resting porcine neutrophils was carried out with [32P]NADPH dialdehyde (oNADPH), [32P]oGTP and [32P]oATP. p49-phox and p63-phox showed 10-times higher affinities for both oGTP and oATP than for oNADPH, suggesting that they are nucleoside triphosphate (NTP)-binding proteins, rather than the NADPH-binding site of the oxidase. In addition, oNADPH markedly inhibited the affinity labeling of p49-phox with [32P]oGTP and [32P]oATP, well reflecting its inhibitory effect on the oxidase activity in the cell-free system, which was previously reported to propose the NADPH-binding site in a cytosolic component. Stimulation of porcine neutrophils with either myristic acid or phorbol myristate acetate resulted in great enhancement of the oxidase activity, and in considerable translocation of p49-phox and p63-phox. Nevertheless, the affinity labeling of the stimulated cell membranes in both cases revealed no labeled bands corresponding to molecular masses of 49 kDa and 63 kDa. p49-phox derived from the stimulated membranes had lost its [32P]oGTP binding ability in contrast with that from resting cytosol, suggesting that the NTP-binding sites of the two cytosolic components may be desensitized on NTP binding in their translocated states.

Etiological role of phagocytes in Kawasaki disease

The numbers of immature neutrophils and monocytes in the peripheral blood are increased in the acute phase of Kawasaki disease. These phagocytes contain toxic granules and vacuoles in the cytoplasm. Phagocytes are primed and activated to release active oxygen species, lysosome enzymes and chemical mediators, which injure cultured endothelial cells and vascular smooth muscle cells. One of the possible factors causing cardio-vascular complications in Kawasaki disease is these activated phagocytes. Some microbial agents or their products such as toxins may activate neutrophils and monocytes, but the real cause remains unknown.

In vivo effects of recombinant human granulocyte colony-stimulating factor on normal neutrophil function and membrane effector molecule expression

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is now undergoing clinical trials. We investigated the effects of rhG-CSF on the function of neutrophils in vivo in healthy volunteers. rhG-CSF (0.5 micrograms/kg) was injected subcutaneously for 6 consecutive days. The number of neutrophils in peripheral blood decreased transiently within an hour, and thereafter increased 2-10-fold compared to the control 6 to 8 h after injection. The circulating neutrophils remaining during this early neutropenic period showed increases in such functions as random motility, chemotaxis, phagocytosis and superoxide anion production. On the other hand, the function of neutrophils which increased 6 to 8 h after rhG-CSF injection was normal. No decrease of neutrophil function was observed following the use of rhG-CSF. CD33-positive cells increased 3 days after rhG-CSF administration. CD11a (LFA-1) expression on the membranes circulating neutrophils decreased 6 h after rhG-CSF administration. This phenomenon suggested that neutrophils adhered to the reticuloendothelial system during neutropenia, and that there was an influx of CD11a-negative mature cells into the circulatory pool thereafter. All our findings suggest that rhG-CSF enhances the function of normal neutrophils in vivo, and that it is effective against microbial infection very soon after administration.

[Neutrophil dysfunction in chronic neutrophilic leukemia without rearrangements of bcr and immunoglobulin heavy chain genes]

A 67-year-old man was admitted to our hospital with abdominal distension due to hepatosplenomegaly. The peripheral blood revealed Hb content 6.5 g/dl, platelet count 4.7 x 10(4)/microliter, and WBC count 105.8 x 10(3)/microliter with 88% of mature neutrophils. The neutrophil alkaline phosphatase score was 421. Bone marrow aspiration revealed hypercellularity with increased megakaryocytes and myeloid hyperplasia. 46, XY, del 20(q 11) without Philadelphia chromosome was identified by cytogenetic study. The patient was diagnosed as having chronic neutrophilic leukemia and was successfully treated with busulfan, but he died of atypical mycobacteriosis about 20 months later. Analysis of neutrophil function demonstrated diminution of deformability, random mobility, and chemotaxis, but almost normal phagocytosis and bactericidal capacity. Southern analysis showed no rearrangements of breakpoint cluster region (bcr) gene and immunoglobulin heavy chain gene.

Comparison of transforming growth factor-beta and a macrophage- deactivating polypeptide from tumor cells. Differences in antigenicity and mechanism of action

A factor in medium conditioned by mouse tumor cells was shown previously to suppress the capacity of mouse peritoneal macrophages to undergo a respiratory burst and to kill protozoal pathogens (macrophage deactivation factor, MDF). Recently, pure transforming growth factor-beta (TGF-beta) proved to be a potent macrophage deactivator as well. Two lines of evidence suggest that MDF is not identical with TGF-beta. First, rabbit anti-TGF-beta IgG neutralized the respiratory burst-suppressing activity of TGF-beta without affecting the bioactivity of MDF, even when the latter was treated with acid to activate potentially latent TGF-beta. Second, in contrast to MDF, which decreases the affinity of the NADPH oxidase for NADPH, permeabilized macrophages that had been deactivated with TGF-beta displayed the same Km and Vmax of the oxidase as activated macrophages. As with MDF, TGF-beta had no effect on two other potential control points over the secretion of respiratory burst products, namely, hydrogen peroxide catabolism or glucose uptake. Finally, neither MDF nor TGF-beta affected the extent or affinity of binding of phorbol diesters to macrophages, the activity or cofactor requirements for protein kinase C, or the ability of protein kinase C to translocate quantitatively from cytosol to membrane fractions in response to phorbol diesters. Thus, 1) MDF is not identical with TGF-beta, and 2) in contrast to the activation or deactivation of macrophages by numerous other agents, TGF-beta regulates macrophage respiratory burst capacity at a level other than the apparent affinity of the oxidase for its substrate.

Comparison of transforming growth factor-beta and a macrophage- deactivating polypeptide from tumor cells. Differences in antigenicity and mechanism of action

A factor in medium conditioned by mouse tumor cells was shown previously to suppress the capacity of mouse peritoneal macrophages to undergo a respiratory burst and to kill protozoal pathogens (macrophage deactivation factor, MDF). Recently, pure transforming growth factor-beta (TGF-beta) proved to be a potent macrophage deactivator as well. Two lines of evidence suggest that MDF is not identical with TGF-beta. First, rabbit anti-TGF-beta IgG neutralized the respiratory burst-suppressing activity of TGF-beta without affecting the bioactivity of MDF, even when the latter was treated with acid to activate potentially latent TGF-beta. Second, in contrast to MDF, which decreases the affinity of the NADPH oxidase for NADPH, permeabilized macrophages that had been deactivated with TGF-beta displayed the same Km and Vmax of the oxidase as activated macrophages. As with MDF, TGF-beta had no effect on two other potential control points over the secretion of respiratory burst products, namely, hydrogen peroxide catabolism or glucose uptake. Finally, neither MDF nor TGF-beta affected the extent or affinity of binding of phorbol diesters to macrophages, the activity or cofactor requirements for protein kinase C, or the ability of protein kinase C to translocate quantitatively from cytosol to membrane fractions in response to phorbol diesters. Thus, 1) MDF is not identical with TGF-beta, and 2) in contrast to the activation or deactivation of macrophages by numerous other agents, TGF-beta regulates macrophage respiratory burst capacity at a level other than the apparent affinity of the oxidase for its substrate.

Deactivation of macrophages by transforming growth factor-beta

Macrophage activation--enhanced capacity to kill, in a cell that otherwise mostly scavenges--is essential for host survival from infection and contributes to containment of tumours. Both microbes and tumour cells, therefore, may be under pressure to inhibit or reverse the activation of macrophages. This reasoning led to the demonstration of macrophage deactivating factors from both microbes and tumour cells. In some circumstances the host itself probably requires the ability to deactivate macrophages. Macrophages are essential to the healing of wounds and repair of tissues damaged by inflammation. Yet the cytotoxic products of the activated macrophages can damage endothelium, fibroblasts, smooth muscle and parenchymal cells (reviewed in ref. 6). Thus, after an inflammatory site has been sterilized, the impact of macrophage activation on the host might shift from benefit to detriment. These concepts led us to search for macrophage deactivating effects among polypeptide growth factors that regulate angiogenesis, fibrogenesis and other aspects of tissue repair. Among 11 such factors, two proteins that are 71% similar proved to be potent macrophage deactivators: these are transforming growth factor-beta 1 (TGF-beta 1) and TGF-beta 2.

Macrophage deactivation. Altered kinetic properties of superoxide-producing enzyme after exposure to tumor cell-conditioned medium

Incubation of activated mouse peritoneal macrophages with tumor cell-conditioned medium (TCM) results in their deactivation, as measured by ability to release reactive oxygen intermediates and kill protozoal pathogens. The mechanism of suppression by macrophage deactivation factor (MDF) was studied. Inhibition of H2O2 release could not be overcome by increasing the concentration of phorbol diesters used to trigger the respiratory burst. Deactivated macrophages consumed H2O2 at the same rate as activated cells (t1/2, 35-40 min for 25 nmol H2O2 per 10(6) peritoneal cells). They transported glucose with the same kinetics (Km, 1 mM; Vmax, approximately 100 nmol per 6 min per milligram cell protein), and maintained similar intracellular concentrations of NADPH and NADP (approximately 0.62 mM and approximately 0.11 mM, respectively), as measured by enzymatic cycling methods and determinations of the volume of cell water (3.6 microliter/mg cell protein). To study the kinetics of the PMA-triggered NADPH oxidase in cell lysates, mixed detergents were used (deoxycholate and Tween 20). These stabilized the oxidase for approximately 3.3-fold longer than deoxycholate alone, which was used in previous studies. Incubation of activated macrophages in MDF resulted in a marked increase in the Km of the oxidase for NADPH, from 0.06 mM to 0.67 mM. The Vmax fell approximately 1.7-fold. These kinetic changes, together with the measured intracellular concentration of NADPH, account quantitatively for the suppression of H2O2 release by deactivated macrophages, and are nearly the mirror image of the kinetic changes observed during macrophage activation.

Release of arachidonate and reduction of oxygen. Independent metabolic bursts of the mouse peritoneal macrophage

Diverse particulate and soluble stimuli trigger two metabolic bursts in mouse peritoneal macrophages important in the inflammatory and/or cytotoxic actions of the cells: release, oxygenation, and further metabolism of arachidonic acid from endogenous phospholipids and reduction of molecular oxygen to reactive intermediates. We tested the hypothesis that the release of arachidonic acid or formation of its metabolites are obligatory intermediate steps in triggering the NADPH oxidase that reduces O2 to O-2. With phorbol diesters as stimuli, the following inhibitors of phospholipase A2 and lipoxygenase suppressed release of H2O2 at nontoxic concentrations (microM range): p-bromophenacyl bromide, quinacrine, eicosatetraenoic acid, nordihydroguaiaretic acid, and phenidone. Indomethacin and acetylsalicylic acid were ineffective. However, the suppressive effect of the first five agents on H2O2 release could be attributed to their suppression of macrophage glucose uptake at the same concentrations, a previously unrecognized effect of these compounds. Further, concanavalin A, wheat germ agglutinin, and thrombin each stimulated abundant arachidonate release without H2O2 release. Finally, noncytolytic concentrations of cycloheximide and/or emetine suppressed arachidonate release without affecting H2O2 secretion triggered either by phorbol esters or zymosan. Release and metabolism of arachidonic acid and secretion of reactive oxygen intermediates appear to be two frequently coincident but mutually independent metabolic pathways in the mouse peritoneal macrophage.

Enzymatic basis of macrophage activation. Kinetic analysis of superoxide production in lysates of resident and activated mouse peritoneal macrophages and granulocytes

To compare the kinetics of the O-2-generating enzyme in nonactivated and activated macrophages and granulocytes from the mouse peritoneal cavity, we sought conditions in which the activity of this enzyme in cell lysates was comparable to that in intact cells. Pretreatment of macrophages with 10 mM diethyldithiocarbamate inhibited endogenous superoxide dismutase by 70% and enhanced O-2 secretion up to 15-fold, so that it was comparable to H2O2 secretion. O-2 secretion was terminated by detergent lysis and reconstituted by addition of NAD(P)H to the lysates. Optimal detection of O-2 production in lysates depended on prior stimulation of the respiratory burst, lysis with 0.05% deoxycholate rather than any of 4 other detergents or sonication, acetylation of the cytochrome c used as an indicator, and addition of NADPH rather than NADH. Kinetic analysis using NADPH-reconstituted deoxycholate lysates, together with spectra of oxidized and reduced cells, failed to reveal either marked differences in the Vmax of the O-2-generating enzyme or correlations between O-2 secretion and cytochrome b559 content among 5 macrophage populations whose H2O2 secretion ranged from 0 to 365 nmol/90 min/mg of protein. In contrast, the Km of the oxidase for NADPH varied markedly and inversely with the capacity of the intact cells to secrete O-2 or H2O2: J774G8 histiocytoma cells, 1.43 mM; resident macrophages, 0.41 mM; proteose peptone-elicited macrophages, 0.20 mM; casein-activated macrophages, 0.05 mM; NaIO4-activated macrophages, 0.05 mM; and granulocytes, 0.04 mM. These results suggest that macrophage activation, a process that enhances oxygen-dependent antitumor and antimicrobial functions, may equip the cell to secrete increased amounts of reactive oxygen intermediates largely by increasing the affinity of the oxidase for NADPH.

Activation of guinea pig polymorphonuclear leukocytes with soluble stimulators leads to nonrandom distribution of NADPH oxidase in the plasma membrane

Guinea pig polymorphonuclear leukocytes (PMN) were briefly activated with soluble stimulators such as sodium myristate (SM) or phorbol myristate acetate (PMA) and then disrupted by the nitrogen cavitation method to study the subcellular distribution of NADPH oxidase, which is responsible for O2 - generation. Fc-receptor and 5'-nucleotidase activities were measured as plasma membrane markers. 1) The homogenate was first fractionated by differential centrifugation. The O2- -generating activity of PMN activated either by SM or PMA was recovered in a 2 X 10(4) g pellet which contained a large amount of granules and about 50% of the plasma membrane markers, but not in a 1 X 10(5) g pellet which consisted of plasma membranes and few granules. 2) Further separation of the 2 X 10(4) g pellet from PMA-activated PMN was attempted by an iso-osmotic Percoll density gradient centrifugation. The O2- -generating activity was recovered in light fractions in which plasma membrane markers were found, but neither in specific nor in azurophil granules. The 1 X 10(5) g pellet showed a similar distribution of the plasma membrane markers to that of the 2 X 10(4) g pellet, except that the peak of the O2- -generating activity was much smaller on an identical density gradient. The results showed that NADPH oxidase is located in the plasma membranes precipitated by centrifugation at 2 X 10(4) X g but not in the ones precipitated at 1 X 10(5) X g. The results suggest that the plasma membrane of activated PMN has a mosaic distribution of NADPH oxidase.

Polymorphonuclear leukocyte-mediated cytolysis induced by animal lectin

Nine animal lectins, i.e., Sarcophaga peregrina agglutinin, Balanus roseus agglutinin, Aplysia kurodai agglutinin, Balanus balanoides agglutinin, Tetraclita squamosa japonica agglutinin, Misgurnus anguillicaudatus lectin, Asterina pectinifera agglutinin, Helix aspersa agglutinin and Helix pomatia agglutinin, were tested for induction of cytolysis mediated by polymorphonuclear leukocytes. Among them, S. peregrina agglutinin and B. roseus agglutinin lysed murine target cells in co-operation with polymorphonuclear leukocytes (PMNs) from the peritoneal cavity of mice. PMNs can lyse various tumor cells in the presence of S. peregrina agglutinin, although normal spleen cells were also lysed. This lectin-dependent cytolysis by PMNs was inhibited by galactose, a sugar which is specifically recognized by S. peregrina agglutinin. S. peregrina and B. roseus agglutinins were inhibitory to in vivo development of MM46 tumor cells. These results suggest that PMNs can lyse various target cells in the presence of appropriate animal lectins and that some animal lectins participate in tumor rejection.

Mechanisms of lectin and antibody-dependent polymorphonuclear leukocyte-mediated cytolysis

The mechanisms of tumor lysis by polymorphonuclear leukocytes (PMNs) were investigated. In antibody-dependent PMN-mediated cytolysis (ADPC), sensitized tumor cells were specifically lysed via Fc receptors on PMNs. On the other hand, lectin-dependent PMN-mediated cytolysis (LDPC) caused nonspecific lysis of several murine tumors after recognition of carbohydrate moieties on the cell membrane of both PMNs and tumor cells. Both ADPC and LDPC depended on glycolysis, and cytotoxicity was mediated by reactive oxygen species; LDPC was dependent on superoxide and ADPC on the myeloperoxidase system. The participation of reactive oxygen species in PMN cytotoxicity was also demonstrated by pharmacological triggering with phorbol myristate acetate. These results indicate that reactive oxygen species have an important role In tumor killing by PMNs and that ADPC and LDPC have partly different cytolytic processes as well as different recognition steps.

Induction of polymorphonuclear leukocyte-mediated cytolysis by wheat germ agglutinin and antitumor antibody

The role of polymorphonuclear leukocytes (PMNs) as effector cells in tumor lysis was investigated in vitro. PMNs were obtained from the peritoneal cavity of C3H/He Mice injected ip with 2 ml of 12% casein sodium. These PMNs could lyse murine MM46 tumor cells in the presence of the plant lectin, wheat germ agglutinin (lectin-dependent PMN-mediated cytolysis). PMNs alone did not cause cytolysis. PMNs obtained 6 hr after casein injection were effective against tumor target cells but those obtained 3 hr after the injection were not. Other lectins, such as concanavalin A, phytohemagglutinin, pokeweed mitogen, soybean agglutinin, Ulex europaeus agglutinin, Lens culinaris hemagglutinin and Bauhinia purpurea agglutinin, did not cooperate with PMNs in tumor lysis. Antitumor antibody was another mediator that induced tumor lysis in cooperation with PMNs (antibody-dependent PMN-mediated cytolysis). These results indicate that PMNs can lyse tumor cells in the presence of appropriate mediators.

Preparation of polymorphonuclear leucocyte-plasma membranes which show Fc receptor activity

A plasma membrane-rich fraction was prepared from guinea pig peritoneal polymorphonuclear leucocytes (PMNs) by a nitrogen cavitation method. Fc receptor activity was measured in the fraction. The activity showed a Kd of 5 X 10(-7) M IgG and a maximum binding of 33 pmol IgG/mg protein when measured with an immune complex made with bovine serum albumin and rabbit anti-(bovine serum albumin) immunoglobulin G. Properties of the Fc receptor in the plasma membrane fraction were similar to that in intact PMNs. It is proposed that the Fc receptor activity and 5'-nucleotidase activity are markers for plasma membranes of these cells.

An Fc-receptor activity of plasma membranes from guinea-pig peritoneal polymorphonuclear leucocytes

Plasma membranes prepared from guinea-pig peritoneal polymorphonuclear leucocytes showed an immune-complex-binding activity that corresponded well with the activity in intact cells. The characteristics of this activity were reversible binding, dependence on the Fc portion of antigen-complexed IgG (immunoglobulin G), competition with aggregated IgG and independence from energy metabolism. These results support the conclusion that the binding activity found in the isolated plasma membranes is an Fc-receptor activity of guinea-pig peritoneal polymorphonuclear leucocytes. The activity showed Kd = 6.7 x 10(-8) M-IgG and maximum binding of 17 pmol of IgG/mg of membrane protein when measured with an immune complex of alpha-amylase and homologous guinea-pig anti-(alpha-amylase) IgG. Inhibition of the Fc-receptor activity by a series of various salts indicated the contribution of the hydrophobic interaction to the binding. Inhibitory effects of salts or metal-chelating reagents on the Fc-receptor activity were also observed on superoxide generation by these cells induced by the immune complex, suggesting a role of the Fc receptor as the immune-complex-binding site responsible for the initiation of superoxide generation.