Expansion of CD4+CD16+ blood monocytes in patients with chronic renal failure undergoing dialysis: possible involvement of macrophage colony-stimulating factor

A novel subpopulation of blood monocytes coexpressing CD16 antigen and low levels of CD14 antigen (CD14+CD16+ monocytes) has recently been identified, and expansion of these CD14+CD16+ monocytes has been reported under some pathological conditions. In this study, we examined the immunophenotype of blood monocytes in patients with chronic renal failure (CRF) who were undergoing hemodialysis (HD, n = 52) or continuous ambulatory peritoneal dialysis (CAPD, n = 36) using two-color immunofluorescence flow cytometry. The percentage and absolute number of CD14+CD16+ monocytes were significantly higher (p < 0.001) in both HD and CAPD patients compared with those in healthy control subjects. We also determined the plasma concentrations of hematopoietic growth factors and cytokines using an enzyme-linked immunosorbent immunoassay. The plasma levels of macrophage colony-stimulating factor (M-CSF) were markedly increased in both HD and CAPD patients relative to the normal controls. The plasma M-CSF levels correlated significantly with the number of CD14+CD16+ monocytes in the whole group of subjects. These findings suggest that elevated endogenous M-CSF levels may participate in the expansion of CD14+CD16+ monocytes in CRF patients undergoing dialysis.

In vivo administration of granulocyte colony-stimulating factor increases the surface expression of sialyl-Lewis(x) on neutrophils in healthy volunteers

We examined the in vivo effect of granulocyte colony-stimulating factor (G-CSF) on the surface expression of putative counterligands for endothelial selectins on neutrophils in healthy volunteers. G-CSF (50 microg/m2/day) was administered subcutaneously to 5 healthy volunteers for 4 days. The expression of surface antigens on neutrophils was determined by flow cytometry and monoclonal antibodies. G-CSF administration increased the number of leukocytes, mainly of neutrophils, which was associated with an increase in the expression of the high-affinity Fc receptor for IgG (FcRI, CD64) and CD14 on neutrophils. G-CSF administration decreased the surface expression of L-selectin on neutrophils, whereas it increased the expression of sialyl-Lewisx but not Lewisx on neutrophils. These findings suggest that G-CSF participates in the neutrophil-endothelial cell interactions in vivo by modulating the expression of adhesion molecules and ligands for endothelial selectins on neutrophils.

Effect of alcohol intake on the levels of plasma homocysteine in healthy males

Hyperhomocysteinemia in chronic alcoholics has been reported, but it remains unclear whether relatively low alcohol intake compared with the previous reports affects the plasma homocysteine level. To investigate this issue, we performed two studies, a population-based study and an alcohol withdrawal study. An analysis of plasma homocysteine levels in a population of 236 healthy males showed no significant association between alcohol consumption and other tested parameters. In the withdrawal study, the subjects with a history of daily alcohol consumption (81.8 +/- 33.0 g/d, mean +/- SD, 40-150g/d, range) abstained from alcohol for 4 wk. After withdrawal, the levels of serum gamma-glutamyl transpeptidase, aspartate aminotransferase, triglycerides, and high-density lipoprotein cholesterol significantly decreased, but the plasma homocysteine level did not change. These results suggest that alcohol intake, at least as far as the amount of beverages our study subjects consumed, has no effect on the plasma homocysteine level in healthy males.

[Homeostasis of antioxidant status in hemodialysis patients]

Oxidative stress, which occurs when there is excessive free-radical production or low antioxidant levels, makes significant contributions to pathogenesis in many human diseases. Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis. For these patients, oxidative stress and increased lipid peroxidation may contribute to increased risk of atherosclerosis. The aim of this study was to determine if hemodialysis patients were associated with disturbance of homeostasis of antioxidant status. In this experiment, total antioxidant status of serum is measured by its ability to inhibit generation of free radicals from 2,2'-amino-di-[3-ethylbenzthiazole sulphonate] by metmyoglobin and hydrogen peroxide. Status of radical scavengers, such as serum total protein, albumin, uric acid and total bilirubin, was also measured. Blood were collected from three different episodes of hemodialysis. In the first group (n = 29), blood were collected before and after hemodialysis. In the second group (n = 29), blood were collected after dialysis and before next hemodialysis. In the third group (n = 8), blood were collected before hemodialysis. After last hemodialysis, patients started ingesting vitamin C and blood were collected before next hemodialysis. There was a marked reduction of total antioxidant status after hemodialysis in the first group. There was a marked increase in total antioxidant status before next hemodialysis in the second group. High doses of vitamin C caused increase in total antioxidant status in the third group. In conclusion, disturbance of homeostasis of total antioxidant status were observed in patients receiving hemodialysis. This may play a role in the pathogenesis in these groups.

[Plasma macrophage colony-stimulating factor level and changes of monocyte subpopulations in chronic renal failure patients treated with hemodialysis]

This study was carried out on 52 hemodialysis (HD) patients. The concentrations of macrophage colony-stimulating factor (M-CSF) in plasma and dialysate were measured by ELISA. Plasma M-CSF level increased in HD patients. M-CSF levels of dialysate were under the detection limit. The monocyte subpopulations were studied using double staining of CD14 and CD16 by flow cytometry. The percentage and absolute number of CD14+/CD16+ cells were much higher in HD patients (p < 0.001, respectively, Mann-Whitney U-test). A new subpopulation of blood monocyte, CD14+/CD16+, has been identified which possesses the features of tissue macrophage. The elevations of this subpopulation were also reported under some pathological conditions, and in subject treated with recombinant M-CSF. HD is the pathological condition which induces the increase in plasma M-CSF as well as change of monocyte subpopulation.

Evaluation of the expression of human CAP18 gene during neutrophil maturation in the bone marrow

To understand the gene expression of CAP18 (18-kDa cationic antibacterial protein), a member of cathelicidins, we evaluated mRNA and protein expression of CAP18 using human bone marrow cells and mature neutrophils. Northern blot analysis revealed that CAP18 mRNA was expressed more abundantly in bone marrow cells than mature neutrophils, whereas Western blot analysis indicated that CAP18 protein was more abundant in mature neutrophils than bone marrow cells. Consistent with this, in situ hybridization using bone marrow cells demonstrated that the expression of CAP18 mRNA was neutrophil lineage-specific and was observed primarily in myelocytes (>95%) with limited expression in more immature cells (promyelocytes) and mature cells (metamyelocytes, band cells, and segmented neutrophils). Furthermore, immunohistochemical study indicated that, coincident with the increase of CAP18 mRNA levels, CAP18-positive cells increased markedly at myelocyte stage, and the increased levels remained almost constant (>95%) in metamyelocytes, band cells, and segmented neutrophils, although the mRNA levels were remarkably reduced in these cells. Together these observations indicate that CAP18 gene transcription likely occurs lineage- and stage-specifically at the myelocyte stage of neutrophil maturation in the bone marrow and results in the synthesis and cytoplasmic accumulation of CAP18, which is present in the subsequent stages of neutrophil maturation.

[In vitro activities of faropenem against clarithromycin resistance Helicobacter pylori isolates]

Agar dilution and semi-solid agar dilution were used to determine the MIC of faropenem (FRPM) against 24 H. pylori isolates. FRPM was active against clarithromycin resistance H. pylori isolates. And, the MICs obtained by both methods were in agreement. The results suggest that FRPM was not affected by pH and is a clinically useful oral antibiotic for the eradication therapy of H. pylori infections.

Granulocyte colony-stimulating factor administration increases serum concentrations of soluble selectins

In order to explore the possible role of granulocyte colony-stimulating factor (G-CSF) in the inflammatory process, we examined the serum concentrations of soluble selectins (sL-selectin, sE-selectin and sP-selectin) following in vivo administration of G-CSF to five healthy volunteers and 12 neutropenic patients with haematological malignancies. The serum concentrations of both sL-selectin and sE-selectin were slightly but significantly increased after G-CSF administration in the healthy volunteers. The serum concentrations of all three selectins were significantly increased after G-CSF administration in the neutropenic patients concomitant with an increase in their neutrophil counts. These findings suggest that G-CSF may participate in the leucocyte-endothelial cell interactions in vivo.

Altered surface expression of effector cell molecules on neutrophils in myelodysplastic syndromes

The surface expression of effector cell molecules on neutrophils was examined in 18 patients with myelodysplastic syndromes (MDS) and 20 healthy control subjects. The MDS patients were further classified as low clinical risk (L-MDS, n=7) and high clinical risk (H-MDS, n=11). The expression of Fc receptors for IgG (FcR), complement receptors (CR) and cellular adhesion molecules on neutrophils was determined by flow cytometry and monoclonal antibodies. The effect of granulocyte colony-stimulating factor (G-CSF) and tumour necrosis factor-alpha (TNF) on L-selectin shedding and CR up-regulation on neutrophils was also examined. The percentage of FcRI-positive neutrophils and CD11b/CR3 expression on neutrophils were significantly increased in the H-MDS patients when compared to the controls. In contrast, the expression of FcRII, FcRIII, L-selectin, LFA-1 and CD18 on neutrophils was significantly reduced in the H-MDS patients compared with the controls. The L-MDS neutrophils exhibited lower expressions of CR1, L-selectin, LFA-1 and CD18 than those of the controls. Neutrophils from some H-MDS patients showed impaired L-selectin shedding and CR up-regulation after stimulation with G-CSF or TNF, although these were not significantly different when assessed in the whole H-MDS group. These findings suggest that an altered surface expression of effector cell molecules and an impaired modulation of cellular adhesion molecules on neutrophils may contribute to the increased susceptibility to bacterial infections in MDS patients.

[Plasma macrophage colony-stimulating factor, granulocyte macrophage colony-stimulating factor and granulocyte colony-stimulating factor levels in continuous ambulatory peritoneal dialysis patients]

From a pathophysiological perspective, several studies have been performed on cytokines in chronic renal failure patients treated with continuous ambulatory peritoneal dialysis (CAPD). Because the peritoneal macrophages in CAPD patients produce some cytokines and the urinary secretion route for cytokines lost in those patients, CAPD patients are considered to have different plasma cytokine levels. Among the various cytokines, research on certain inflammatory cytokine levels has been reported. In studies of CAPD patients, peripheral blood and dialysate can be used as specimens. There are two methods of research. One involves determining the cytokine concentration in specimens and culture supernatant, while the other is to determine the mRNA expression of mononuclear cells in specimens and cultured mononuclear cells. The plasma levels of macrophage colony stimulating factor (M-CSF), granulocyte macrophage colony stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) were measured in CAPD patients without peritonitis. Plasma M CSF, GM CSF and G-CSF levels in CAPD patients were higher than those in healthy volunteers (p < 0.0001).

[The influence of local anesthetics on human leukocyte functions studied by micro whole blood collection and flowcytometry]

The influence of local anesthetics (pure bupivacaine and lidocaine with no preservative) on human leukocyte functions was examined. (a) The effect of bupivacaine on the phagocytosis of granulocyte was studied by bioassay. (b) The effect of lidocaine on the appearance of iC3b receptor (CR3) of granulocyte and monocyte (which is an important cell-adhesion-factor) was examined using flowcytometry. (c) The influence of lidocaine on phagocytosis of granulocyte and monocyte and on respiratory burst of granulocyte was examined using flowcytometry. (d) The influence of lidocaine on phagocytosis and that on respiratory burst were compared. These studies revealed that both phagocytosis and respiratory burst were inhibited by lidocaine, and the inhibition of respiratory burst was stronger than the inhibition of phagocytosis by local anesthetics' immunosuppressive effects. It was concluded that the balance of immunosuppressive action due to antimicrobial action and bactericidal ability of local anesthetics determined the occurrence of local bacterial infection.

Alterations of effector cell molecule expression on neutrophils in granulocyte colony-stimulating factor-producing tumour

A 68-year-old man was diagnosed as having a granulocyte colony-stimulating factor (G-CSF)-producing mediastinal tumour. Mediastinotomy was performed, and thereafter the elevated leucocyte count and serum G-CSF concentration returned to the normal range. The surface expression of effector cell molecules on neutrophils was serially examined. Before operation, the expression of FcRI and CR1 was increased but the expression of FcRIII and L-selectin was reduced in the patient. The altered expression of these molecules returned to the normal levels after operation. These findings suggest that G-CSF produced by the tumour modulated neutrophil effector cell molecule expression in the patient.

[A novel method for detection of anti-neutrophil cytoplasmic antibody (ANCA) using flow cytometry]

It has been reported that anti-neutrophil cytoplasmic antibody (ANCA) is a specific serological marker for systemic necrotizing vasculitis, such as Wegener's granulomatosis, microscopic polyarteritis and idiopathic crescentic glomerulonephritis. Although the standard method for ANCA detection enplays an indirect immunofluorescence technique (IIF), the method is not objective. We attempted to detect ANCA by a more objective method using flow cytometry.

MATERIALS AND METHOD

Thirty ANCA positive sera (cytoplasmic in 4, perinuclear in 26) and 20 ANCA negative sera including 2 sera with anti-nuclear antibody (ANA) detected by standard IIF were used for this study. For flow cytometric analysis, heparinized blood was taken from normal healthy volunteers. Neutrophils in the heparinized blood was incubated with human recombinant tumor necrosis factor alpha (rTNF alpha) in order to facilitate reaction between the antigens of ANCA and ANCA. Primed neutrophils were incubated with sera. After washing with phosphate buffered saline, immunofluorescence-labeled antibody against human IgG was added and incubated. The mean intensity of fluorescence (MIF) of the neutrophils was measured by flow cytometry (FACS, Becton-Dickinson CO., U.S.A.) for each sample. ANCA was considered positive by flow cytometric analysis if MIF of the sample was over the mean +2SD for normal human sera.

RESULTS

By flow cytometric analysis, ANCA was detected in all ANCA positive samples by IIF and in 3 ANCA negative samples by IIF, of which 2 had ANA. However, it was possible to discriminate serum with positive ANCA from serum with positive ANA by flow cytograms because ANA reacted with the nuclei of both lymphocytes and neutrophils showing two peaks on the histogram.(ABSTRACT TRUNCATED AT 250 WORDS)

Granulocyte colony-stimulating factor administration modulates the surface expression of effector cell molecules on human monocytes

Granulocyte colony-stimulating factor (G-CSF) has been shown to stimulate human neutrophil functions, both in vitro and in vivo. We examined the effects of G-CSF administration on the surface expression of effector cell molecules on human neutrophils and monocytes. G-CSF (50 micrograms/m2/d) was administered subcutaneously to five healthy volunteers once a day for 7 d. Venous blood was obtained immediately before and after the completion of G-CSF administration and 1 week after the last G-CSF administration. The surface expression of complement receptors (CR), Fc receptors for IgG(FcR) and cellular adhesion molecules on human neutrophils and monocytes were determined by indirect immunofluorescence using flow cytometry and monoclonal antibodies. The expression of CR1, CR3, FcRI and FcRII on neutrophils increased significantly after G-CSF administration and then decreased after the last G-CSF administration. The expression of human leucocyte adhesion molecule-1 (LAM-1) on neutrophils reflected the above expression. On the other hand, the administration of G-CSF increased the expression of CR1, CR3, FcRI and FcRIII on monocytes. The expression of CR1, CR3 and FcRI on monocytes then decreased after the last G-CSF administration, whereas the expression of FcRIII remained at an increased level. These findings indicate that G-CSF administration modulates the expression of effector cell molecules on circulating monocytes as well as on neutrophils, resulting in enhanced defence against selected infections or in potentiation of the tumouricidal capacity of phagocytes in cancer patients.

[G-CSF and G-CSF receptor]

Relationship between leucocytosis and G-CSF blood concentration were examined. Increase in blood concentration of G-CSF of surgical patient and dialysis patient with leucocytosis were noticed. Determination of G-CSF receptor on leucocyte was performed by the flow cytometry using biotinylated G-CSF. Modulation of G-CSF receptor on leucocyte at surgery and dialysis was identified in vivo. Studies of G-CSF blood concentration and modulation of G-CSF receptor are useful in analysis of dynamics of leucocyte and analysis of infectious disease.

Complement receptor type 1 (CR1) deficiency on neutrophils in myelodysplastic syndrome

We present a patient with myelodysplastic syndromes (MDS) whose neutrophils exhibited defective expression of complement receptor type 1 (CR1). A 73-year-old man was admitted with an evolution of MDS from RA into RAEBT according to the FAB classification of MDS. The neutrophil alkaline phosphatase (NAP) score was zero. The surface expression of membrane effector molecules on neutrophils was determined by indirect immunofluorescence using flow cytometry and monoclonal antibodies. The expression of CR1 on neutrophils as identified by staining with CD35 was defective in the patient, and the expression of other complement receptors (CR3 and CR4), Fc receptors and adhesion molecules was normal. CR1 deficiency and defective NAP score on neutrophils in the patient might account for impairment of common storage pool, presumably novel intracellular secretory vesicles.

Local anesthetic lidocaine inhibits the effect of granulocyte colony-stimulating factor on human neutrophil functions

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) enhanced superoxide (O2-) release in human neutrophils stimulated by the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) and inversely regulated the surface expression of cellular adhesion molecules, leukocyte adhesion molecule-1 (LAM-1) and CD11b/CD18 leukocyte integrin, on human neutrophils; that is, rhG-CSF downregulated the expression of LAM-1 and upregulated the expression of CD11b on neutrophils. The cationic local anesthetic lidocaine inhibited not only FMLP-induced O2- release in neutrophils but also FMLP-induced CD11b upregulation and LAM-1 downregulation on neutrophils in a dose-dependent manner. Lidocaine also abolished the priming effect of rhG-CSF for enhanced release of O2- in neutrophils and inhibited rhG-CSF-induced CD11b upregulation and LAM-1 downregulation on neutrophils in a dose-dependent manner. These findings suggest that lidocaine inhibits human neutrophil functions, such as adherence to endothelial cells, by interfering with the expression of cellular adhesion molecules on neutrophils, and that lidocaine might have anti-inflammatory properties by inhibiting the effect of inflammatory cytokines.

Granulocyte colony-stimulating factor down-regulates the surface expression of the human leucocyte adhesion molecule-1 on human neutrophils in vitro and in vivo

The leucocyte adhesion molecule-1 (LAM-1) is the human homologue of the murine peripheral lymph node homing receptor, MEL-14, and might play a crucial role in neutrophil localization at inflammatory sites. We have reported previously that recombinant human granulocyte colony-stimulating factor (rhG-CSF) stimulates or enhances several neutrophil functions in vivo, as well as in vitro. To further explore the possible role of G-CSF in inflammation we studied the effect of rhG-CSF on the surface expression of LAM-1 on human neutrophils, both in vitro and in vivo. The expression of LAM-1 by human neutrophils was investigated by indirect immunofluorescence using flow cytometry and monoclonal antibodies anti-Leu-8 and TQ1. A whole blood analysis was performed to minimize in vitro manipulation. Most circulating human neutrophils expressed LAM-1 on the cell surface. Brief exposure of neutrophils to rhG-CSF in vitro decreased the surface expression of LAM-1. rhG-CSF down-regulated neutrophil LAM-1 expression in a time- and dose-dependent manner. Neutrophils from healthy volunteers and from patients who were receiving rhG-CSF exhibited a decreased expression of LAM-1 after rhG-CSF administration, and the expression thereafter returned or overshot the pretreatment level after stopping rhG-CSF administration. These findings indicate that rhG-CSF down-regulates the surface expression of LAM-1 on human neutrophils in vivo, as well as in vitro, and G-CSF might participate in neutrophil-endothelial cell interaction in inflamed tissue.

[Carrier state and comparative study of methicillin-resistant Staphylococcus aureus from the staff and patients]

The nasal carriage of Staphylococcus aureus in 529 staff was screened. S. aureus from staff and patients whose minimum inhibitory concentration (MIC) of methicillin was larger than 12.5 micrograms/ml by agar dilution was defined as Methicillin-resistant S. aureus (MRSA). Coagulase typing was performed by DENKA SEIKEN kit. Hands of ward staff were screened before and after contact with the MRSA carriers and after hand washing. The nasal acquisition rate of S. aureus and MRSA for staff was 27.6% and 8.5%. The rate of ward staff for nasal carriers of MRSA was 91.1%. Coagulase type II strains from ward staff and inpatients were dominant. In some cases MRSA was detectable after hand washing: In MRSA infection ward staff played a dangerous role as a vector.

[Free concentration and protein binding of ceftriaxone]

Ceftriaxone (CTRX) was administered in dose of 1 g 30 minutes intravenous drip infusion to 5 healthy volunteers. Cefpiramide (CPM) and cefotetan (CTT) were administered as control antibiotics. The serum concentrations of total and free drugs, using ultrafiltration, were assayed by bioassay and HPLC. Protein binding rates and pharmacokinetic parameters were calculated. Free concentration of antibiotics were following orders in each sampling time: CTRX greater than CTT greater than CPM. Mean free concentrations of CTRX at 0 hour and at 8 hours after intravenous drip infusion was more than 20 micrograms/ml and more than 2 micrograms/ml. Even at 24 hours after intravenous drip infusion free concentrations of CTRX were detectable. Mean half life in beta phase by HPLC was following orders: CTRX (7.5 hours) greater than CPM (5.4 hours) greater than CTT (4.7 hours). Mean protein binding rates were following orders: CPM (98%) greater than CTT (94%) greater than CTRX (92%).

CONCLUSIONS

Characteristic of CTRX is high free drug concentration and long half life.

[Organ transplantation and laboratory tests]

The media has recently been featuring organ transplantation from various viewpoints. Furthermore, Novel Prizes 1990 for Medical & Physiological fields were awarded to Drs. JE Murray and ED Thomas, both pioneers of clinical transplantation. Our topic has been timely indeed. This symposium mainly dealt with laboratory tests vs. various types of organ transplantation. In reality though, only kidney and bone marrow transplantations have been practiced in Japan; thus, Dr. I Yokoyama, University of Pittsburgh, discussed liver transplantation. First, Dr. K Uchida lectured on the recent advancement of immunosuppressive drugs and improvement in the clinical outcome of kidney transplantation. Serum creatinine determination is the only parameter for rejection besides renal biopsy. Drs. K Miyamura & Y Morishima discussed about PCR method to detect MRD (minimal residual diseases). There are positive relationships between the remaining leukemic cells and the relapse of leukemia even though the patients are in clinical remission. Dr. H Funada dealt with the importance of "sterile room treatment" for bone marrow transplantation. It protects patients from infection, minimizes GVHD and prolongs survival time after transplantation. Dr. Yokoyama stressed the importance of back-up system, i.e. drug-monitoring, coagulation tests, pathological examination, biochemical tests, blood transfusion services for successful liver transplantations. Dr. T Fukunishi discussed the importance of developing the organ donor and coordinator system to promote kidney transplantation from cadaver. He also dealt with virus antibody tests for selecting donors. All discusssions stressed on the importance of the 24-hour laboratory back-up system performing emergency tests but no specific laboratory test for organ transplantation was necessary.

[Antibacterial activity of imipenem in combination with ampicillin against methicillin-resistant strains of Staphylococcus aureus]

Imipenem (IPM) and beta-lactams have been reported to possess a synergistic relationship in their activities against methicillin (DMPPC)-resistant strains of Staphylococcus aureus (MRSA). The purpose of this study was to determine activities of IPM and ampicillin (ABPC) singly and in combination against MRSA. Activities of the 2 antibiotics against 19 strains of S. aureus resistant to DMPPC were investigated by means of the checkerboard method, the disk diffusion technique and the killing-curve method. MICs of DMPPC against these strains determined using the agar dilution method were greater than or equal to 100 micrograms/ml and MICs of IPM and ABPC ranged from 12.5 to 100 micrograms/ml and from 12.5 to 50 micrograms/ml, respectively, when used singly. The following results were obtained with the checkerboard method: Synergistic effects and additive effects were found against 13/19 and against 6/19 strains, respectively, and no antagonistic effect was found according to the FIC (fractionary inhibitory concentration) index. The disk diffusion technique indicated synergistic results. Killing-curves with the following drug concentration combinations were examined in Mueller-Hinton broth against 5 fosfomycin(FOM)-resistant and 5 FOM-susceptible stains: (1) IPM 12.5 micrograms/ml, (2) ABPC 25 micrograms/ml, (3) IPM 12.5 micrograms/ml + ABPC 25 micrograms/ml, (4) IPM 6.25 micrograms/ml + ABPC 25 micrograms/ml, (5) IPM 6.25 micrograms/ml + ABPC 12.5 micrograms/ml, (6) IPM 6.25 micrograms/ml + ABPC 12.5 micrograms/ml + FOM (fosfomycin) 25 micrograms/ml, (7) IPM 12.5 micrograms/ml + ABPC 25 micrograms/ml + FOM 50 micrograms/ml, (8) FOM 50 micrograms/ml. The following results were obtained with the killing-curve method; (1) Synergistic effects were found against 8/10 strains and no antagonistic effect was found with the combinations of IPM and ABPC. (2) Synergistic effects were found against 3/5 strains and no antagonistic effect was found with the combinations of IPM, ABPC and FOM against 5 FOM-susceptible strains.

CONCLUSIONS

IPM in combination with ABPC produced synergistic effects against MRSA. This combination therapy should be evaluated in treating MRSA infections.

[Antibacterial activity of local anesthetics]

In order to study the antibacterial activity of local anesthetics quantitatively, we procured their minimum inhibitory concentration (MIC), killing curves and postantibiotic effect (PAE), using the standard colony of Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 14990 and Pseudomonas aeruginosa NCTC 10490. Both bupivacaine and lidocaine had bactericidal activity at a clinical concentration. MIC of the former was lower than that of the latter, and it means that bupivacaine has a greater antibacterial activity than lidocaine. At the same concentration, the commercial solutions, such as Xylocaine and Marcain, which contain preservatives, showed a greater antibacterial activity than the pure anesthetic solutions which contain no preservatives. However, the preservatives had no bactericidal activity, but weak bacteriostatic activity.

[Antibacterial activities and electron microscopic studies of imipenem in combination with fosfomycin against methicillin and fosfomycin resistant strains of Staphylococcus aureus]

Imipenem (IPM) and fosfomycin (FOM) have been reported to possess a synergistic relationship in their activities against both methicillin (DMPPC)-susceptible and -resistant strains of Staphylococcus aureus. However it was not concluded whether these antibacterial activities were bacteriostatic or bactericidal. The purpose of this report is to elucidate this point clearly. Activities of the 2 antibiotics against 15 strains S. aureus resistant to both DMPPC and FOM were investigated by means of the killing-curve method and electron microscopic studies. MICs of DMPPC and FOM against these strains determined using the agar dilution method were greater than or equal to 50 micrograms/ml and MICs of IPM by the broth dilution method ranged from 12.5 to 50 micrograms/ml. The killing-curves with the following drug concentration combinations were examined in Mueller-Hinton broth: 1. FOM 25 micrograms/ml, 2. FOM 25 micrograms/ml + IMP 1/2 MIC, 3. IPM 1MIC, 4. FOM 25 micrograms/ml + IPM 1 MIC and 5. FOM 25 micrograms/ml + IPM 2MIC. Morphological changes produced in 1 strain by 2 of the combinations, 2. FOM 25 micrograms/ml + IPM 1/2 MIC and 4. FOM 25 micrograms/ml + IPM 1MIC, were observed using scanning and transmission electron microscopy. The following results were obtained; (1) The synergistic effects were found in 6/15 strains (40%) and no antagonistic effect was found. (2) Electron microscopic observation showed that IPM in combination with FOM caused lysis of the cells.

CONCLUSIONS

IPM in combination with FOM produced bactericidal and bacteriolytic effects on DMPPC-resistant S. aureus (MRSA). This combination therapy should be evaluated for FOM resistant MRSA infections.

[Corneal crystalline deposits in multiple myeloma]

Two cases of multiple myeloma with corneal opacity were reported. Their chief complaint was blurred vision, and general check-up performed prior to cataract operation revealed that one case had multiple myeloma of IgG-kappa and another, of IgG-lambda type. Two corneal buttons obtained at the time of lamellar keratoplasty operations in the IgG-kappa case were studied immunohistopathologically as well as electron microscopically. Corneal opacity observed with a slit lamp was localized at the anterior stroma of both corneas. Immunohistological studies revealed that the deposit was IgG-kappa chain. Transmission electron microscopy disclosed electron-dense extracellular deposits that exhibited a honeycomb appearance and parallel linear structures with a periodicity of 12nm.

[Influence of human albumin on bactericidal or antibacterial activities of cephems and monobactams]

Influence of human albumin on bactericidal or antibacterial activities of 11 beta-lactams were examined. The 11 beta-lactams included second generation cephems (cefsulodin, cefotiam and cefmetazole), third generation cephems (ceftazidime, latamoxef, cefmenoxime, cefoperazone, cefotetan and cefpiramide) and monobactams (carumonam and aztreonam). The micro-broth-dilution method was used to determine antibacterial activities. Bactericidal activities were determined using the time-kill method. Used in the broth-dilution method were 2 media, MUELLER-HINTON broth (MHB) and the same medium supplemented with 5 g human albumin/d1 (MHB-A). The first experiment was to compare minimum inhibitory concentrations (MICs) determined in MHB were compared with those in MHB-A of 6 antibiotics against Staphylococcus aureus FDA 209P JC-1, of 7 antibiotics against Escherichia coli ATCC 25922 and of 5 antibiotics against Pseudomonas aeruginosa NCTC 10490. MICs using MHB-A were higher than MIC using MHB for 2 of the 6 antibiotics against S. aureus, and for all the 7 antibiotics against E. coli, and for 3 of the 5 antibiotics against P. aeruginosa. The second experiment was done to compare MICs of 5 antibiotics determined in MHB-A with those determined in MHB against 10 clinical isolates of S. aureus, of 6 antibiotics against 10 clinical isolates of Klebsiella pneumoniae and of 6 antibiotics against 10 clinical isolates of P. aeruginosa. The results obtained in the second experiment were varied for different antibiotics and different strains of organisms, and same antibiotics produced different results for different strains. MICs determined in MHB-A were lower than those in MHB for antibiotics with relatively low protein binding rates against 22 of 170 isolates tested (12.9%), whereas the former was higher than the latter against 103 out of 170 isolates tested (60.6%). MICs of antibiotics with relatively high protein binding rates showed an opposite trend. In the third experiment, time-kill curves were determined in the 2 media for 5 antibiotics against S. aureus FDA 209P JC-1, for 6 drugs against E. coli ATCC 25922 and for 5 drugs against P. aeruginosa NCTC 10490. The concentrations of these antibiotics used were 1/2 x MIC, 1 x MIC and 2 x MIC. MICs determined in the first experiment were used here. Time-kill curves determined in MHB-A didn't reflect MICs determined in MHB. Using MHB-A, antibiotics with lower MICs determined in MHB-A showed bactericidal activities in lower concentrations. Human albumin influenced antibacterial or bactericidal activities of beta-lactams.(ABSTRACT TRUNCATED AT 400 WORDS)

[Effects of cephem antibiotics on ethanol metabolism]

Disulfiram-like reactions have been reported in patients receiving cephem antibiotics which possess a mercaptomethyltetrazole (Me-TZ) side chain in their molecular structure. The present study focused on the elucidation of the relationship between the formation of Me-TZ and its inhibitory action on alcohol metabolism after treatment with the cephem antibiotics. The cumulative urinary excretion of Me-TZ was determined in healthy volunteers and laboratory animals after i.v. administration of the cephem antibiotics: cefmetazole (CMZ), cefoperazone (CPZ) and latamoxef (LMOX). In humans, monkeys and rodents, the extent of urinary excretion of Me-TZ was found in the order of CPZ greater than LMOX greater than CMZ-treatment. To assess their influences on dehydrogenation of ethanol (EtOH) and acetaldehyde (AcH), rats and monkeys were treated with a single or multiple i.v. dose of Me-TZ and cephem antibiotics prior to the EtOH treatment. The blood EtOH levels were not affected with either the Me-TZ or the cephem pretreatments. On the contrary, the AcH levels were significantly elevated with each of the pretreatments. The dose response curves for AcH levels showed parallel lines corresponding to the urinary excretion of Me-TZ, i.e., CPZ greater than LMOX greater than CMZ-treatment. These results suggest that there are some differences in the disulfiram-like reactions among animal species and antibiotics, which will be attributed to the intrinsic distribution and stability of each of the antibiotics in the body.