A new enzymatic assay for selectively measuring conjugated bilirubin concentration in serum with use of bilirubin oxidase

A new enzymatic assay for selectively measuring conjugated bilirubin concentration in serum with use of bilirubin oxidase (BOD) has been developed. At pH 5.5 BOD can oxidize only conjugated bilirubin in the presence of reagents such as sodium fluoride and N-acetylcysteine which can decrease BOD reactivity to unconjugated bilirubin and bilirubin covalently bound to albumin (delta bilirubin). The resulting decrease in absorbance at 450 nm is linearly related to the concentration of conjugated bilirubin in serum. The BOD in this new assay was confirmed to oxidize conjugated bilirubin, and neither unconjugated nor delta bilirubin, based on both its reactivity to unconjugated bilirubin and HPLC results. This assay was found to give satisfactory results, such as in terms of the range of measurement, the reproducibility of the results, the lack of interference with coexisting substances in serum and the stability of the reagent solutions, in practical applications. The serum conjugated bilirubin concentrations determined using this assay correlate well with those determined by the HPLC analysis. This assay can be used for accurate monitoring of changes in the conjugated bilirubin concentration in patient sera. These findings suggest that the conjugated bilirubin assay is useful for fractional determination of bilirubin in icteric sera.

Production of proinflammatory cytokines by resident tissue macrophages after phagocytosis of apoptotic cells

It is generally believed that apoptosis is not associated with inflammation. However, we have found that phagocytosis of apoptotic cells by PMA-treated THP-1 cells and human monocyte-derived macrophages led to the production of proinflammatory cytokines, notably IL-8. These macrophages were obtained either by PMA treatment or by M-CSF treatment, possibly affecting the cytokine production after phagocytosis of apoptotic cells. In order to exclude the possibility, we employed resident tissue macrophages such as Kupffer cells and alveolar macrophages in this study and examined the production of cytokines after phagocytosis of apoptotic cells. Kupffer cells produced proinflammatory cytokines MIP-2 and TNF-alpha at the mRNA level. The MIP-2 protein was also detected by means of ELISA. Alveolar macrophages also produced the MIP-2 protein after phagocytosis of apoptotic cells. Furthermore, apoptotic thymocytes induced a similar response by these macrophages. These findings do support the notion that macrophages are apt to produce proinflammatory cytokines after phagocytosis of apoptotic cells.

Rapid separation of DNA constituents, bases, nucleosides and nucleotides, under the same chromatographic conditions using high-performance liquid chromatography with a reversed-phase column

Four components of three sets of DNA constituents, bases, deoxyribonucleosides and deoxyribonucleoside 5'-monophosphate, were sufficiently resolved under one set of chromatographic conditions using high-performance liquid chromatography with a reversed-phase column (Zorbax ODS) and the solvent 0.4 M NH4H2PO4 (pH 3.5). The effect of pH and salt concentration in the solvent on the retention of these compounds in the column was thoroughly investigated. Proportionality of peak height to the content, and reproducibility and recovery of the four bases were satisfactory under appropriate conditions and as little as 1 microgram of DNA could be analysed for its base composition by this method.

Cytokine production by macrophages in association with phagocytosis of etoposide-treated P388 cells in vitro and in vivo

Chemotherapy and radiotherapy are performed for cancer patients with the hope that dying cancer cells are safely scavenged by phagocytic cells such as macrophages. In this study, we examined cytokine production by macrophages during and after the phagocytosis of etoposide-treated P388 cells in vitro and in vivo. Etoposide caused apoptosis as early as 5 h after treatment, as assessed as to the exposure of phosphatidylserine, increase in membrane permeability and DNA ladder formation. Phagocytosis by phorbol myristate acetate (PMA)-treated THP-1 cells occurred marginally when P388 cells were treated with etoposide for 10 h, while it occurred significantly with P388 cells treated for 24 h, as evidenced by flow cytometry and confocal microscopy. PMA-treated THP-1 cells produced pro-inflammatory cytokines, such as interleukin (IL)-1alpha, IL-8 and macrophage migration inhibitory factor (MIF), but not anti-inflammatory cytokines among those tested at the mRNA level during and after the phagocytosis of apoptotic cells. IL-8 and MIF were also produced at the protein level, and the IL-8 production was dependent on cell-to-cell contact when the plasma membranes of apoptotic cells were intact enough not to leak one of the cytoplasmic enzymes, lactate dehydrogenase. In addition, etoposide-treated P388 cells induced neutrophil infiltration as well as MIP-2 production upon injection into the peritoneal cavity of either normal mice or mice with sterile peritonitis. When macrophages ingesting and/or binding apoptotic P388 cells were isolated from the mice with sterile peritonitis using a cell sorter, they were found to produce MIP-2 upon culture.

Interaction of phagocytes with apoptotic cells leads to production of pro-inflammatory cytokines

It is generally believed that apoptosis is not associated with inflammation. To explore the possibility that the interaction of phagocytes with apoptotic cells provides a negative or null signal for inflammation, we examined the cytokine production by thioglycollate-induced peritoneal exudate cells (PEC) upon interaction with a murine T cell clone (CTLL-2) cultured in the absence of interleukin-2 (IL-2). Coculturing of PEC with apoptotic CTLL-2 cells led to the production of not only anti-inflammatory cytokines but also pro-inflammatory ones, notably MIP-2, at the mRNA level, and neutrophils were accumulated in vivo in response to the culture supernatant. Our findings suggest the possibility that apoptosis may be associated with leukocyte infiltration in vivo in some situations.

Antimicrobial activity of lipoprotein particles containing apolipoprotein Al

Human plasma in vitro inhibits the growth of coagulase negative staphylococci, S. epidermidis, which may be pathogenic in the immunocompromised host. To determine the antimicrobial components, serum was fractionated by column chromatography, which revealed that elution areas where lipoproteins can be yielded had high antimicrobial activity against S. epidermidis. Therefore, lipoprotein fractions, including very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL), were separated by ultracentrifugation and incubated with S. epidermidis. All 3 lipoprotein fractions suppressed bacterial growth within the first 3 h but VLDL enhanced bacterial growth after 9 h of incubation compared with the control. HDL, however, inhibited bacterial growth throughout 21 h of incubation. To confirm these results, serum from healthy volunteers was separated by ion exchange column chromatography and again by HPLC to purify the antimicrobial fraction. In the protein analysis with gradient polyacrylamide-SDS gel, apolipoprotein Al (apo Al), which is a major apolipoprotein of HDL, was detected in the antimicrobial fraction. Therefore, this fraction was loaded onto an immunoaffinity column coupled with the anti-apo Al monoclonal antibody (Mab). Unbound fraction had no antimicrobial activity, but anti-S. epidermidis activity was recovered from the bound fraction which consisted mainly of apo Al, All and apo C in protein composition. These results indicated that the antimicrobial activity was associated with the apo Al-containing lipoprotein particles (HDL). This property of HDL may directly affect bacterial growth and promote the self-defense mechanisms of normal and immunocompromised individuals.

Characteristics of coronary heart disease in Japanese taxi drivers as determined by coronary angiographic analyses

Several epidemiological studies have shown that the prevalence of ischemic heart disease is higher in occupational drivers than in people with other occupations. Although occupation categories can be surrogate measures for coronary risk factors, the relationships between taxi driving and severity of coronary heart disease (CHD) has not been investigated. Even more important, the contribution of risk factors to the severity of CHD in taxi drivers remains unclear. Our study tested the hypothesis that taxi driving could be associated with the severity of CHD. We also examined the relation between this occupation and risk factors and social lifestyle. We analyzed the coronary angiograms of 57 consecutive male taxi driver patients and compared them with those of 215 age-adjusted male non-taxi-driver patients. The number of diseased vessels and risk factors were compared between two groups. The prevalence of myocardial infarction and multi-vessel disease was higher in the taxi-driver patients than in the non-taxi-driver patients. The taxi-driver patients had higher prevalence of body mass index (BMI), diabetes, and smoking, higher levels of low-density lipoprotein cholesterol (LDL-C), and lower levels of apolipoprotein AI (ApoAI). Multiple logistic regression analysis showed that multi-vessel disease was associated with BMI and diabetes mellitus in taxi-driver patients. The taxi-driver patients were characterized by more extensive coronary atherosclerosis associated with higher prevalence of diabetes mellitus and obesity. These characteristics may be explained by in part their working environment.

Incidence of latex allergy in atopic children and hospital workers in Japan

The incidence of latex-induced allergy has been reported to be increasing in Europe and the US but not in Japan. We thus measured latex-specific IgE antibodies and latex-specific IgG antibodies in sera from 196 atopic children with low serum IgE levels (under 1,000 U/ml; group 1), 108 atopic children with high serum IgE levels (over 1,000 U/ml; group 2) and 601 hospital employees (group 3). Atopic children were diagnosed as having asthma, atopic dermatitis and/or food intolerance. One out of group 1 (0.5%) and 11 out of group 2 (10.2%) were found to have latex-specific IgE by radioallergosorbent assay (RAST), and 7 were further found to be positive for latex antigen by skin test. Fifty-five percent of group 1, 65% of group 2 and 9.7% of group 3 were found to have latex-specific IgG over 100 units/ml by enzyme linked immunosorbent assay (ELISA). Prior to our diagnosis most of the children and employees did not realize they were allergic to latex. These data suggest that caution should be taken regarding latex allergy when atopic children have to be operated upon as atopic children tend to be sensitized to the latex antigen after even minimal contact with latex products.

Hydrodynamics-based gene delivery of naked DNA encoding fetal liver kinase-1 gene effectively suppresses the growth of pre-existing tumors

Antiangiogenic gene therapy is a promising strategy for cancer treatment, which generally requires highly efficient delivery systems. To date, success of this strategy has depended almost exclusively on the delivery of high titers of viral vectors, which can result in effective transgene expression. However, their cytotoxicity and immunogenicity are a major concern for clinical applications. Recent advances in delivery efficiency of naked DNA could potentially meet the requirement for both high transgene expression and minimal side effects. To investigate whether naked DNA can be used for antiangiogenic cancer therapy, an expression plasmid was generated that encodes a soluble form of fetal liver kinase-1 (Flk-1) gene, a receptor for vascular endothelial growth factor (VEGF). Hydrodynamic injection of this plasmid resulted in close to 0.1 mg/ml of soluble Flk-1 protein in mouse serum and blocked VEGF-driven angiogenesis in matrigel in vivo. The same delivery significantly suppressed the growth of two different pre-existing subcutaneous tumors, Renca renal cell carcinoma and 3LL lung carcinoma. CD31 immunohistochemistry revealed that the tumor-associated angiogenesis was also highly attenuated in soluble Flk-1-treated mice. Thus, expression of genes by hydrodynamics-based gene delivery of naked DNA appears to be a promising approach for antiangiogenic cancer gene therapy.

A 38 kDa precursor protein of aqualysin I (a thermophilic subtilisin-type protease) with a C-terminal extended sequence: its purification and in vitro processing

The precursor of aqualysin I, an extracellular subtilisin-type protease produced by Thermus aquaticus, consists of four domains: an N-terminal signal peptide, an N-terminal pro-sequence, a protease domain, and a C-terminal extended sequence. In an Escherichia coli expression system for the aqualysin I gene, a 38 kDa precursor protein consisting of the protease domain and the C-terminal extended sequence is accumulated in the membrane fraction and processed to a 28 kDa mature enzyme upon heat treatment at 65 degrees C. The 38 kDa precursor protein is separated as a soluble form from denatured E. coli proteins after heat treatment. Accordingly, purification of the 38 kDa proaqualysin I was performed using chromatography. The purified precursor protein gave a single band on SDS-polyacrylamide gels. The precursor protein exhibited proteolytic activity comparable to that of the mature enzyme. The purified precursor protein was processed to the mature enzyme upon heat treatment. The processing was inhibited by diisopropyl fluorophosphate. The processing rate increased upon either the addition of mature aqualysin I or upon an increase in the concentration of the precursor, suggesting that the cleavage of the C-terminal extended sequence occurs through an intermolecular self-processing mechanism.

Protection and performance effects of ankle bracing

We investigated the protection afforded to ankle ligaments by ankle supports and the extent to which these were associated with a diminution of motor performance. Eleven volunteers were subjected to a 10 degrees tilt in four directions (inversion, eversion, plantar flexion and dorsiflexion) on a rocking platform. Three-dimensional videography was used to record complex ankle kinematics. The prophylactic ankle supports used were a semi-rigid brace, a lace-up cloth brace, and taping. The ankle supports provided similar initial protection against acute ligamentous inversion sprains. The semi-rigid ankle brace produced a smaller restriction of plantar flexion-dorsiflexion movement than either the lace-up cloth brace or taping.

Improved methods for detection and serotyping of coagulase from Staphylococcus aureus

Improved methods for detection and serotyping of staphylocoagulase were concomitantly devised. We devised an improved method for detection of coagulase activity on agarose film in the same manner as single radial immunodiffusion. The amounts of reagents required for detection of coagulase on agarose film were successfully diminished by adding polyethylene glycol (PEG) to the original formula described by Boothby et al. Using microplates in another improved method for coagulase serotyping, the amount of reaction fluid required was considerably less compared with the conventional tube method. PEG was found to be also effective to increase the efficacy of coagulase serotyping. In the presence or absence of anti-coagulase antisera, culture supernatants of staphylococcal strain grown in brain heart infusion broth were incubated with the reaction fluid containing bovine fibrinogen, rabbit plasma, 6-amino caproic acid, polyethylene glycol 6,000. Coagulase activity was visualized as a turbid mass formed in the wells. Turbid mass formation due to coagulase activity was type-specifically inhibited in the presence of type-specific antisera. Detailed procedures of the methods are precisely described with some preliminary results obtained by the methods.

Effect of highly purified coagulase and culture filtrate on virulence and immunity of a coagulase-negative mutant of staphylococcus aureus BB

The virulence of the coagulase-deficient mutant BB-Cgl- 1301 (50% lethal dose [LD50] for mice by the intravenous route) was compared with that of its parental strain, Staphylococcus aureus BB. The BB strain produced free coagulase of serotype I, whereas the mutant 1301 did not. Mice were infected with strain 1301, alone or in combination with a highly purified coagulase type I or type II solution, or with concentrated culture filtrates of parent strain BB or mutant strain 1301. The ratios of the LD50S of 1301 and its combinations to that of BB ranged from 34.9 to 461. Combining strain 1301 with a concentrated culture filtrate of BB (BB-CF2.5) was the most effective for enhancement of its virulence. When mice were infected with a combination of strain 1301 and BB-CF2.5, the LD50 of strain 1301 (1.72 mg of cells [wet weight]) was decreased to 0.13 mg (1.3 x 10(8) CFU). This LD50 yielded the smallest ratio, 34.9, as compared with the LD50 of BB (0.00373 mg). In contrast, when the mice subcutaneously immunized with strain 1301 and BB-CF50 were intravenously challenged by strain BB, the LD50 for the immunized mice was 17.4 times the LD50 for the unimmunized control mice (0.0429 mg as compared with 0.00246 mg), indicating that combination was the most effective for enhancement of mouse immunization with strain 1301. However, combining strain 1301 with the highly purified sample of coagulase increased neither the virulence nor the immunizing power of mutant strain 1301.

Cell-type specificity of l-leucyl l-leucine methyl ester

l-Leucyl l-leucine methyl ester (LeuLeuOMe) is a lysosomotropic agent which is converted to a membranolytic compound by dipeptidyl peptidase I and kills human leukocytes such as CD8+ T cells and monocytes but not B cells. The reagent has also been used in mice on the assumption that the cell-type specificity to murine leukocytes is the same as that to human leukocytes. During study on the effect of LeuLeuOMe on antigen-driven IL-2 production using murine splenocytes as antigen-presenting cells, however, we noticed that murine B cells were sensitive to LeuLeuOMe. We therefore examined the cell-type specificity using murine splenocytes and peritoneal macrophages. Flow cytometric analysis revealed that the most sensitive cells to LeuLeuOMe were CD8+ cells and that CD19+ cells (B cells) were as sensitive as CD3+ cells (T cells). Murine splenic B cells, which were either positively or negatively sorted with a cell sorter, were also sensitive to LeuLeuOMe, whereas human peripheral blood B cells, which were positively sorted, were not. Peritoneal macrophages were the most insensitive to LeuLeuOMe. Thus, this study demonstrated that the cell-type specificity to murine leukocytes is different from that to human leukocytes.

[A study of methicillin-resistant Staphylococcus aureus (MRSA) infection in the urological field]

Clinical backgrounds of 35 patients with urogenital infection, from whom methicillin-resistant Staphylococcus aureus (MRSA) was isolated, were analyzed. Susceptibilities of these MRSA strains to various antimicrobial agents were also measured. Out of 35 MRSA strains, 29, 4 and 2 were isolated from urine, pus and sputum specimens, respectively, showing a definitely high isolation rate from urine. As for underlying diseases, 22 patients (62.8%), 11 (31.4%) and one each had a malignant tumor of the urinary tract or genital organ, prostatic hypertrophy, urolithiasis and vesicoureteral reflux, respectively. Patients aged at over 60 years numbered 20 (57%), and 32 patients (91.4%) were treated with some antimicrobial agent at the time of MRSA isolation. Out of 35 strains, 17 were isolated after total cystectomy with urinary diversion or transurethral surgery. As for the state of MRSA infection, 9 and 26 patients had single and polymicrobial infections, respectively, but none of patients had serious symptoms definitely thought to be caused by MRSA. On evaluation of susceptibilities of MRSA to various antimicrobial agents, the MRSA strains were found to be sensitive to minocycline, netilmicin and ofloxacin. From these results, MRSA strains isolated from patients treated in the field of urology were thought to rarely cause serious infectious symptoms, especially true for those isolated from the urine.

[Studies on phage type, beta-lactamase activity and sensitivity of multiple drug-resistant Staphylococcus aureus isolated from clinical specimens to cefmetazole]

The 868 strains of S. aureus were isolated at the Department of Pediatrics, Third Hospital and Aoto Hospital, The Jikei University, School of Medicine and the Kanagawa Prefectural Nursing and Hygienic School Hospital during 6 months from May to October in 1981. From them 66 strains not sensitive to CEZ were selected by a 3-concentration disk method. A total number of 54 strains except for 12 isolated from the same infant patient was examined for their MIC's for 6 drugs, CMZ, CEZ, CTM, CXM, MCIPC and GM. Moreover, phage typing and beta-lactamase activity determination were carried out in them. 1. Antibacterial activity Sixty-six (7.6) of 868 strains were not sensitive to CEZ. The MIC's of CMZ against these resistant strains were between 1.56 and 50 micrograms/ml with a peak between 3.13 and 6.25 micrograms/ml when the 10(5) cells/ml bacterial suspension were inoculated. CMZ was superior in antibacterial activity to CEZ and CXM by about 4 degrees and to CTM by about 3 degrees. MCIPC and GM has higher antibacterial activity against a few strains than CMZ. However, the number of strains with MIC higher than or equal to 50 micrograms/ml was 17 for MCIPC and 40 for GM, but only 2 for CMZ. Thus, the former 2 drugs were far inferior to the latter one. 2. Phage type (1) Nineteen strains (35.2%) had MIC's for CEZ greater than 50 micrograms/ml and CMZ less than 6.25 micrograms/ml. Seventeen of them belonged to the nontypable. (2) Fourteen (25.9%) had MIC's for CEZ greater than 100 micrograms/ml. Of them 9 were allocated to the group III, 3 to the mixed (I + II + III, I + III) group and 2 to the nontypable. (3) Of 20 strains (37.0%) which had MIC's for CEZ greater than 100 micrograms/ml and CMZ less than 6.25 micrograms/ml 5 belonged to the group I, 3 to the group III and 12 to the nontypable. (4) Five strains classified into the group I were all isolated at the Kanagawa Perfectural Nursing and Hygienic School Hospital. (5) Eleven of 15 strains belonging to the group III were isolated at the Third Hospital, The Jikei University, School of Medicine. (6) Seventeen of 21 strains isolated at the Aoto Hospital, The Jikei University, School of Medicine belonged to the nontypable. (7) Phage type was considered to be influenced by difference in areas, infection within hospitals, etc., 3. beta-Lactamase activity beta-Lactamase activity was demonstrated at levels between 0.07 and 3.26 mumol/min/mg in all 54 strains. There was no correlation between MIC for CEZ or CEZ and beta-lactamase activity. It was suggested that beta-lactamase might not contribute to mechanism of resistance of S. aureus to each drug examined.

Differentiation of specific DNA binding activity of SLE sera from non-specific binding by an addition of dextran sulfate and calcium chloride to the Farr assay system

A new method for differentiation of specific DNA-binding by human sera from non-specific binding was evaluated with sera from patients with systemic lupus erythematosus in different stages of the disease. An addition of dextran sulfate or calcium chloride to Farr's radioimmunoassay mixture reduced non-specific binding of thermally denatured [3H]DNA of the patient sera without much effect on the specific binding. The measurement of DNA-binding value by the sera in these addition systems provides accurate information with regard to the pathophysiological state of the disease.

[Non-destructive and rapid identification of bacteria using near-infrared spectroscopy]

Near-infrared (NIR) spectroscopy has recently come to be applied extensively in agricultural, food and chemical industries, and pharmaceutical science. We have been attempting to expand this method in the field of medical science. For example, we tried to use NIR spectroscopy for determination of bacteria. As the first step of this attempt, we differentiated between Escherichia coli and Staphylococcus aureus using NIR spectroscopy. This method could still further differentiate Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA). Using those results as reference, the true name of bacteria from unknown bacteria was given. Not only untreated bacteria, but also we differentiated untreated MSSA, MSSA cultured in sub MIC concentration of ABPC and heat-killed MSSA. This identification method is sensitive to the bacterial concentration. In the future, the some new idea of a new direction of research from the result of plots of weights from two different bacteria will appear.