Influence of membrane physical state on the lysosomal proton permeability

Influence of membrane physical state on the proton permeability of isolated lysosomes was assessed by measuring the membrane potential with 3,3'-dipropylthiadicarbocyanine iodide and monitoring their proton leakage with p-nitrophenol. Changes in the membrane order were examined by the steady-state fluorescence anisotropy of 1, 6-diphenyl-1,3,5-hexatriene. Both the membrane potential and proton leakage increased with fluidizing the lysosomal membranes by benzyl alcohol and decreased with rigidifying the membranes by cholesteryl hemisuccinate. The proton permeability increased to the maximum of 42% by the benzyl alcohol treatment and decreased to the minimum of 38.1% by the cholesteryl hemisuccinate treatment. Treating the lysosomes with protonophore CCCP increased the proton permeability by 58%. The effects of the membrane fluidization and rigidification can be reversed by rigidifying the fluidized membranes and fluidizing the rigidified membranes, respectively. The results indicate that the proton permeability of lysosomes increased and decreased with increasing and decreasing their membrane fluidity, respectively. Moreover, the lysosomal proton permeability did not alter further if the changes, either an increase or a decrease, in the fluidity exceeded some amount. The results suggest that the proton permeability of lysosomes can be modulated finitely by the alterations in their membrane physical state.

Atrial tachyarrhythmias induced by acetylcholine in tilapia (Oreochromis sp.) isolated atria

1. Effects of the parasympathetic neuromediator acetylcholine (ACh) on atrial tissues vary greatly depending on the species, the type of atrial cells and experimental conditions. The aim of the present study was to investigate, with microelectrode techniques, the arrhythmogenic effects of ACh in tilapia (Oreochromis sp.) isolated atria at room (22-25 degrees C) and high temperature (37 degrees C). 2. Acetylcholine (1-10 micromol/L) shortened action potential duration (APD), depressed action potential plateau and decreased twitch force in tilapia atria, as it did in human atrial fibres. In addition, ACh induced premature responses and re-entrant tachyarrhythmias (TA; frequency range from 7 to 25 Hz) in five of 19 and 14 of 22 tilapia atria tested at room and high temperature, respectively. The higher incidence of ACh-induced TA at 37 degrees C compared with room temperature was statistically significant. 3. The ACh-induced TA consisted of high-frequency and uniform action potentials accompanied by tension oscillation and elevation of diastolic force (flutter). Acetylcholine-induced TA could be readily abolished by atropine (1 micromol/L) and prevented by treatment with agents with local anaesthetic properties, such as 0.1 micromol/L tetrodotoxin or 3 micromol/L quinidine. The antagonistic action of quinidine occurred without significant prolongation of APD. 4. The present findings suggest that pharmacological concentrations of the cholinergic muscarinic agonist ACh readily induce TA (mainly atrial flutter) in tilapia atria, presumably via sodium channel-dependent re-entrant excitation. The poikilothermic tilapia appears to be an appropriate animal model for the study of atrial TA.

[Enantiomer separation by capillary electrochromatography]

As capillary electrochromatography (CEC) combines the desirable features of both high performance liquid chromatography(HPLC) and high performance capillary electrophoresis(HPCE), CEC is an attractive alternative for enantiomer separation. The applications and developments in the field of chiral drug separation by CEC are reviewed with 92 references, including different operating models and different chiral agents and stationary phases.

GP-83 and GP-39, two glycoproteins secreted by human epididymis are conjugated to spermatozoa during maturation

Surface glycoconjugates of spermatozoa are modified during epididymal maturation, which is closely related to the development of sperm function. In addition, recognition of surface glycoconjugates is one of very critical events in sperm-oocyte interaction. The binding of carbohydrate-specific lectins to the human sperm surface during epididymal maturation has been investigated. However, the glycoproteins responsible for lectin binding in sperm maturation are not well documented. This study used wheat germ agglutinin (WGA), peanut agglutinin (PNA) and concanavalin A (Con-A) to identify sperm maturation-related glycoproteins in human epididymis. Histochemical localization revealed that the binding sites of WGA, PNA and Con-A were mainly in the principal cells and luminal contents of the human epididymis, but not in the interstitial regions. Each lectin displayed a fairly distinct regional localization. On Western blots probed with WGA and Con-A, glycoproteins of 83 kDa (GP-83) and 39 kDa (GP-39) were identified in the sperm extracts, epididymal fluid and tissue extracts of the corpus and cauda epididymides, but not in the caput. PNA identified GP-83 in the same manner as WGA and Con-A, but did not recognize GP-39. These results suggest that lectin-binding glycoproteins GP-83 and GP-39 found on mature spermatozoa may be secreted by the principal cells of corpus and cauda epididymis, and conjugated to spermatozoa during their transit in human epididymis.

Purification of GP-83, a glycoprotein secreted by the human epididymis and conjugated to mature spermatozoa

Epididymal secretions are critical for mammalian spermatozoa to acquire both forward motility and an ability to recognize and penetrate oocytes. Previous studies identified two glycoproteins, GP-83 and GP-39, which were secreted by the human epididymis and may be related to maturation of sperm function. In this study, GP-83 was purified from human seminal fluid by DEAE-ion exchange, gel filtration chromatography and preparative gel elution. The isoelectric point (pI) of purified GP-83 was 6.57. Monospecific antiserum to GP-83 was induced in male New Zealand rabbits and confirmed on immunoblots. GP-83 was found in fluid, tissue and sperm extracts of corpus and cauda epididymis, but not in the caput. Immunohistochemical localization identified GP-83 in the luminal contents and in the supranuclear region and cell membrane of principal cells of the corpus and cauda epididymis. GP-83 was found on the anterior acrosome in ejaculated spermatozoa, and shifted to the equatorial region after capacitation and the acrosome reaction.

The complete cDNA sequence of a type II Trichomonas vaginalis virus

Trichomonas vaginalis viruses (TVV), which may regulate P270 gene expression in the protozoan pathogen T. vaginalis, are a group of divergent double-stranded (ds) RNA viruses. In the present study, the complete 4674-bp cDNA sequence of a 4.6-kb ds RNA from a newly identified TVV2-1 isolate was determined. The sequence of the plus-strand mRNA contains four open reading frames, which encode overlapping cap and pol genes in the reading frame 2 and reading frame 1, respectively, and two putative serine-threonine-rich basic proteins VP3 and VP4 in the third reading frame. An 85-kDa capsid protein and a 160-kDa CAP-POL fusion protein were identified in crude viruses by Western blotting experiments using antisera raised against gene-specific oligopeptides. In conjunction with the presence of a potential ribosomal slippery heptanucleotide G GGC CCC within the overlap of the cap and pol genes, these observations suggest that the pol gene of TVV2-1 is translated via a -1 ribosomal frameshifting event during translation of the cap gene. Our results also provide insight into the conservation among divergent dsRNA species from TVV and suggest that the genome of TVV2-1 may encode two extra genes in addition to the cap and pol genes.

Reduction of platelet transfusion- associated sepsis by short-term bacterial culture

BACKGROUND AND OBJECTIVES

There is as yet no suitable routine laboratory test for a blood transfusion service to detect bacterial contamination in platelets. This study evaluates the effectiveness and the applicability of short-term bacterial culture for such a purpose.

MATERIALS AND METHODS

Samples from 5-unit platelet pools were inoculated into an aerobic culture bottle, then monitored for 48 h at 35 degrees C in an automated monitoring and detection system.

RESULTS

26,210 whole-blood-derived platelet components were tested, of which 14 (0.053%) platelet units were found to be contaminated. In addition, nine of the associated red cell units and 4 fresh-frozen plasma units grew the same organisms on culture.

CONCLUSION

Short-duration bacterial culture by an automated system is effective and suitable for routine screening in a regional transfusion center.

HLA-DMA and HLA-DMB genotyping in patients with systemic lupus erythematosus

OBJECTIVE. To investigate the relation of HLA-DMA and DMB alleles to the development of systemic lupus erythematosus (SLE).

METHODS

We studied HLA-DMA and DMB alleles in 108 patients with SLE and 138 healthy controls using the amplification created restriction site method.

RESULTS

The phenotypic frequency of HLA-DMA*0104 was significantly higher in patients with SLE than in healthy controls. The HLA-DMA and DMB alleles were not related to clinical manifestations and various laboratory tests in patients with SLE.

CONCLUSION

HLA-DMA*0104 may be associated with the susceptibility of SLE.

Intrastriatal transplantation of Sertoli cells may improve amphetamine-induced rotation and tyrosine hydroxylase immunoreactivity of the striatum in hemiparkinsonian rats

This study investigated survival and neurotrophic effects of Sertoli cells transplanted in the striatum of 6-hydroxydopamine (6-OHDA)-induced hemiparkinsonian rats. Primary cultures of Sertoli cells were established from 3-week old rats and characterized by associated marker, placental cadherin (P-cadherin). Two months after transplantation, amphetamine-induced rotations of rats transplanted with Sertoli cells were significantly lower than those of control rats. However, restoration of tyrosine hydroxylase (TH) immunoreactivity and Sertoli cells that expressed P-cadherin were only found in the striatum of the rat that showed full recovery from amphetamine-induced rotation 3 months after transplantation without immunosuppression. These results suggest that Sertoli cells transplanted in striatum of hemiparkinsonian rats may survive for at least 3 months, and improve amphetamine-induced rotation and restore TH immunoreactivity.

Hepatitis C virus infection among short-term intravenous drug users in southern Taiwan

The purpose of this study was to determine the correlation between the prevalence of hepatitis C virus (HCV) infection with duration of drug use and other risk factors among drug users. This survey covered 899 male drug users from Kaohsiung Narcotic Abstention Institute and Kaohsiung prison. The prevalence of positive anti-HCV was 67.2% among intravenous drug users (IVDU) and 14.7% among non-intravenous drug users (non-IVDU). Among intravenous (IV) drug users, age and duration of drug use were independently related to HCV seropositivity. Seroprevalence rate for HCV in the IVDU group increased with increasing duration of injection use within the first seven years of drug use. However, the steepest trajectory in seroprevalence of HCV infection occurred within the first four months. Due to the high rate of HCV infection among drug users, investigation of risk behaviors should be routine in such a group. A high frequency of HCV infection was also found among short-term injectors, which indicated that early risk reduction intervention was an important measure in moderating HCV infection.

Biosynthesis of desosamine: construction of a new macrolide carrying a genetically designed sugar moiety

[formula: see text] The appended sugars in macrolide antibiotics are indispensable to the biological activities of these important drugs. In an effort to generate a set of novel macrolide derivatives, we have created a new analogue of methymycin and neomethymycin, antibiotics produced by Streptomyces venezuelae. This analogue 15 carrying a different sugar, D-quinovose, instead of D-desosamine, was constructed by taking advantage of targeted gene deletion combined with a specific pathway-independent C-3 reduction capability of the wild type S. venezuelae.

Pulmonary immunity to Listeria is enhanced by elimination of alveolar macrophages

To determine how resident alveolar macrophages (AM) regulate the antigen-presenting-cell (APC) activities of pulmonary dendritic cells (DC) in the response to particulate antigen, we pretreated Lewis rats intratracheally with liposomes containing clodronate (LIP-CLOD), which eliminated AM in vivo. Controls received saline encapsulated in liposomes (LIP-SAL) or saline alone intratracheally. At Day 3, rats were injected intratracheally with 1 x 10(7) heat-killed Listeria (HKL) and DC purified from lung were examined for their ability to stimulate HKL-immune T cells without added HKL. Only DC from LIP-CLOD-treated rats displayed enhanced APC activities for HKL. A second intratracheal HKL challenge at Day 14 yielded lymphocytic cuffing of the microvasculature in LIP-CLOD-treated lungs only. Intratracheal adoptive transfer of normal syngeneic AM into LIP-CLOD-treated rats suppressed APC activities of DC in vitro and the lymphocytic response in vivo. Bronchoalveolar macrophages from rats treated with LIP-CLOD and HKL showed decreased production of nitric oxide (NO), a potent suppressor of DC and T-helper 1 lymphocyte activities as compared with those of controls. We conclude that eliminating AM in vivo reduces local production of NO and promotes pulmonary cell-mediated immunity to HKL.

HLA-DMA and HLA-DMB genotyping in patients with rheumatic diseases

To investigate the correlation of HLA-DMA and DMB alleles to some rheumatic diseases, HLA-DMA and DMB genes were detected in 11 patients with juvenile rheumatoid arthritis (JRA), 22 patients with psoriatic arthritis, 26 patients with Behcet's disease, 62 patients with ankylosing spondylitis (AS), and 138 unrelated healthy controls. There was no significant difference in phenotypic frequencies of HLA-DMA and DMB alleles between controls and patients with these rheumatic diseases. HLA-DMA and DMB genes are not related to the susceptibility of JRA, psoriatic arthritis, Behcet's disease, and AS.

Seroepidemiology of hepatitis C virus infection among drug abusers in southern Taiwan

The purpose of this study was to determine the risk factors for hepatitis C virus (HCV) infection among drug abusers in southern Taiwan. This survey included 935 drug abusers from Kaohsiung Narcotic Abstention Institute and Kaohsiung prison. The prevalence of anti-HCV antibody was 29.1% among male drug abusers and 19.4% among female drug abusers. The seroprevalence of anti-HCV antibody was 66.4% among intravenous drug abusers and 14.4% among nonintravenous drug abusers. Intravenous drug use, a history of hepatitis, having tattoos, and age were independently related to HCV seropositivity among drug abusers. The prevalence of anti-HCV antibody concentrations significantly increased (10.8-fold) with intravenous drug abuse and with having tattoos (1.7-fold). These findings suggest that hepatitis C virus is mainly transmitted by the parenteral route among drug abusers in southern Taiwan. Due to the high rate of HCV infection among drug abusers, investigation of high-risk behavior should be routine in this group. To prevent HCV infection, emphasis on the use of sterile needles and aseptic procedures in tattooing is important in Taiwan.

A gene cluster for macrolide antibiotic biosynthesis in Streptomyces venezuelae: architecture of metabolic diversity

In a survey of microbial systems capable of generating unusual metabolite structural variability, Streptomyces venezuelae ATCC 15439 is notable in its ability to produce two distinct groups of macrolide antibiotics. Methymycin and neomethymycin are derived from the 12-membered ring macrolactone 10-deoxymethynolide, whereas narbomycin and pikromycin are derived from the 14-membered ring macrolactone, narbonolide. This report describes the cloning and characterization of the biosynthetic gene cluster for these antibiotics. Central to the cluster is a polyketide synthase locus (pikA) that encodes a six-module system comprised of four multifunctional proteins, in addition to a type II thioesterase (TEII). Immediately downstream is a set of genes for desosamine biosynthesis (des) and macrolide ring hydroxylation. The study suggests that Pik TEII plays a role in forming a metabolic branch through which polyketides of different chain length are generated, and the glycosyl transferase (encoded by desVII) has the ability to catalyze glycosylation of both the 12- and 14-membered ring macrolactones. Moreover, the pikC-encoded P450 hydroxylase provides yet another layer of structural variability by introducing regiochemical diversity into the macrolide ring systems. The data support the notion that the architecture of the pik gene cluster as well as the unusual substrate specificity of particular enzymes contributes to its ability to generate four macrolide antibiotics.

Genetic analysis of interleukin-10 promoter region in patients with systemic lupus erythematosus in Taiwan

Overproduction of interleukin-10 (IL-10) may play an important role in the development of systemic lupus erythematosus (SLE) or lupus nephritis. There is also a polymorphic dinucleotide repeat in the human IL-10 promoter region (IL-10PR). Our aim was to study whether or not the IL-10PR alleles contributed to the susceptibility to SLE or lupus nephritis. One hundred SLE patients and 103 healthy controls were studied for IL-10PR by PCR and electrophoretic analysis. The distribution of IL-10PR alleles, genotypes and the sum of both alleles (SBA) from different groups or subgroups were analyzed. SLE patients showed no difference in the distribution of IL-10PR alleles, genotypes and SBA, as compared to healthy controls. Lupus nephritis patients (N = 49) also showed no difference in IL-10PR alleles, genotypes and SBA, as compared to SLE patients without nephritis (N = 51). Of 49 lupus nephritis patients, ten developed end-stage renal disease (ESRD) and four of them were found to suffer from rapid progressive renal failure (RPRF). Patients with RPRF presented much smaller SBA than other ESRD patients (p = 0.005). Lupus nephritis patients carrying small SBA (< 18) suffered from a higher prevalence of RPRF than lupus nephritis patients without small SBA (50% V.S. 0%, p < 0.001, relative risk 82). Our data provide the first evidence of a strong association between IL-10PR and severe progression of lupus nephritis in human patients. In the future, a prospective genetic analysis of IL-10PR for patients with lupus nephritis is recommended. It might be helpful for physicians to identify the lupus nephritis subgroup with a high risk of developing RPRF early, because this might lead to a better therapy and prognosis for these patients.

Characterization of Trichomonas vaginalis virus proteins in the pathogenic protozoan T. vaginalis

The 4.6-kb double-stranded (ds) RNA of Trichomonas vaginalis virus (TVV)-T1 has been shown to encode two overlapping genes, cap and pol. In this study, a serum for specifically detecting viral cap gene product was raised against a recombinant protein, and sera for specifically detecting pol gene product were raised against synthetic oligopeptides. A 75-kDa major protein and a 160-kDa minor protein were detected by anti-CAP serum in a TVV-T1 sample, indicating that the 75-kDa protein is the viral capsid protein. The 160-kDa protein alone was also detected by two distinct anti-POL sera, indicating that the pol gene is expressed as a CAP-POL fusion protein. These results suggest that the TVV-T1 genome is arranged into a cap-pol organization in a manner similar to that of viruses in family Totiviridae.

T cell receptor gene V alpha and V beta usage in patients with rheumatoid arthritis in Taiwan

To investigate the correlation of T cell receptor (TCR) genes to rheumatoid arthritis (RA) in Taiwan, synovial fluid and peripheral blood were examined simultaneously in 14 patients with RA, and peripheral blood only was examined in 15 healthy controls. RNA was extracted from T cell in synovial fluid and peripheral blood, and cDNA was synthesized using the reverse transcription method. Then, TCR-V alpha and V beta gene families were determined using the polymerase chain reaction and slot blot methods. The numbers of TCR-V alpha and V beta families, especially V beta, were decreased in rheumatoid synovial fluid compared with numbers found in the peripheral blood of the same RA patients. TCR-V beta 7 and V beta 8 could be found in the synovial fluid of all patients with positive HLA-DR4. However, there was no significant difference in the numbers of TCR-V alpha and V beta families in peripheral blood of RA patients and the peripheral blood of healthy controls. In conclusion, restricted heterogeneity of TCR-V gene, especially V beta, can be found in synovial fluid of patients with RA. TCR-V beta 7 and V beta 8 may be related to the pathogenesis of HLA-DR4 positive RA patients in Taiwan.

HLA-DP epitope typing using monoclonal antibodies

We have made a panel of murine anti-DP monoclonal antibodies for serological typing of HLA-DP polymorphisms; they can be used in microcytotoxicity (for 7 epitopes) and binding assays (for 8 epitopes). The antibodies detect polymorphic differences in both alpha and beta chains. As immunogens we sometimes used B-lymphoblastoid lines or purified DP molecules but mostly used mouse fibroblast transfectants expressing DP molecules. The DP beta genes were made from a cloned DPB1*0201 gene by replacing its major area of polymorphism with matching stretches of DNA amplified from other alleles; cloned DPA1*01 and DPA1*02 genes were used for transfection along with the beta chain genes. The monoclonal antibodies showed reaction patterns that correlated with the presence of particular amino-acid sequence motifs; thus none of the antibodies is allele-specific. They bind instead to epitopes which are found on a number of different HLA-DP types. We have constructed frequency tables so that the epitope (motif) data can be interpreted as the most likely genotype in each case. The basic assumption to justify this work is that HLA-DP matching or mismatching will likely influence transplant outcome, particularly in bone marrow transplantation. The present challenge is to define permissive and nonpermissive combinations of HLA-DP; it may be that matching for epitopes, rather than for full alleles, will help to resolve this issue.

Redesigning the active-site of an acyl-CoA dehydrogenase: new evidence supporting a one-base mechanism

The acyl-CoA dehydrogenases are a family of related enzymes that share high structural homology and a common catalytic mechanism which involves abstraction of an alpha-proton from the substrate by an active site glutamate residue. Several lines of investigation have shown that the position of the catalytic glutamate is conserved in most of these dehydrogenases (the E2 site), but is in a different location in two other family members (the E1 site). Using site specific in vitro mutagenesis, a double mutant rat short chain acyl-CoA dehydrogenase (rSCAD) has been constructed in which the catalytic glutamate is moved from the E2 to the E1 site (Glu368Gly/Gly247Glu). This mutant enzyme is catalytically active, but utilizes substrate less efficiently than the native enzyme (K(m) = 0.6 and 2.0 microM, and Vmax = 2.8 and 0.3 s-1 for native and mutant enzyme respectively). In this study we show that both the wild-type and mutant rSCADs display identical stereochemical preference for catalysis--abstraction of the alpha-HR from the substrate followed by transfer of the beta-HR to the FAD coenzyme. These results, in conjunction with molecular modeling of the native and double mutant SCAD indicate that the catalytic base in the E1 and E2 sites are topologically similar and catalytically competent. However, analysis of the 1H NMR spectra of the incubation products of these two enzymes revealed that, in contrast to the wild-type rSCAD, the Gly368Glu/Gly247Glu rSCAD could not perform gamma-proton exchange of the product with the solvent, a property inherent to most acyl-CoA dehydrogenases. It is evident that the base in the mutant enzyme has access to the alpha-HR but is far removed from the gamma-Hs. These findings provide further support for a one base mechanism of alpha- and gamma-reprotonation/deprotonation catalysis by acyl-CoA dehydrogenases.

A collagenous cementum-derived attachment protein is a marker for progenitors of the mineralized tissue-forming cell lineage of the periodontal ligament

The periodontal ligament (PDL) is a fibrous and cellular connective tissue that mediates tooth attachment to bone, and it comprises fibroblastic and mineralized tissue-forming (MTF) progenitors. The MTF progenitors are believed to give rise to the cementoblastic and osteoblastic lineages. Cementum attachment protein (CAP) is a collagenous cementum-derived protein which binds strongly to osteoblasts, moderately to PDL cells, and weakly to gingival fibroblasts. The aim of the present study was to determine the relationship between the capacity of PDL progenitors to bind CAP and their potential to express alkaline phosphatase (ALP) and form mineralized-like tissue in culture. Cloned human PDL progenitor populations obtained from nine human donors were assayed for their constitutive capacity to bind CAP and express ALP, and for the dexamethasone-induced potential to form mineralized-like tissue in culture in the presence of ascorbic acid and beta-glycerophosphate. Forty percent of the progenitor clones produced mineralized-like tissue. Two patterns of mineralization were observed: a spread and flat pattern similar to that produced by human bone cells in culture and a nodular ridge-like type resembling that formed by human cementoma-derived cells. A direct correlation was found between the percentage of ALP positive cells in each progenitor clone and the amount of mineralized-like tissue formed (r = 0.565). Similar correlations were found between the number of ALP positive cells and the binding capacity of each clone (r = 0.392) and between the CAP binding capacity and mineralized-like tissue formation (r = 0.584). Multiple regression analysis indicated that the constitutive capacity of a clone to bind CAP and express ALP is directly correlated to its dexamethasone-induced potential to form mineralized tissue (r = 0.675). These results indicate that CAP binding and ALP expression can serve as markers for the identification of MTF progenitors in the heterogeneous cultured population of the human periodontal ligament. These data show for the first time that binding capacity to extracellular components of mineralized tissues can be a marker for mineralized tissue-forming progenitors.

[Determination of adenosine and thymidine in Fritillaria bulbs by dual wavelength ultraviolet spectrophotometry]

A convenient method for the quantitative analysis of adenosine and thymidine in Fritillaria bulbs was developed by means of dual wavelength ultraviolet spectrophotometry. This method has good linear relationship and the interrelated coefficient of standard curve for adenosine and thymidine were all found to be 0.9999. The methanol extracts of four species of Fritillaria have been analyzed with this method. The results show that the the bulbs of four species contain different quantities of adenosine and thymidine, which indicates that the nucleosides may be responsible for the anti-coagulation activity of Fritillaria.

Expression of inducible nitric oxide synthase by macrophages in rat lung

Nitric oxide (NO) is a short-lived free radical that is secreted by pulmonary macrophages (Mø). An inducible isoform of NO synthase (iNOS) catalyses the production of NO and is activated by lipopolysaccharide and certain T-helper(h) 1 cytokines, including interferon-gamma and TNF-alpha. In the present study, iNOS+ interstitial cells were demonstrated in the alveolar wall of normal Lewis rat lung. Enzymatic digests of normal lung showed that approximately one third of pulmonary ED1+ interstitial Mø (IM) were iNOS+ and secreted modest amounts of NO without ex vivo stimulation, whereas normal alveolar macrophages (AM) were iNOS- and showed no basal NO secretion. When incubated with heat-killed Listeria monocytogenes (HKL) in vitro, AM secreted larger amounts of NO than did IM. Recombinant murine GM-CSF stimulated production of NO by AM but not by IM. However, when IM were costimulated with GM-CSF and IFN-gamma, they expressed a marked increase in NO production. Intratracheal challenge with HKL yielded decreased NO production by IM. We conclude that iNOS+ IM are present in normal rat lung, where they regulate the pulmonary cell-mediated immune response to antigen.

Elevated serum liver enzymes in coke oven and by-product workers

Coke oven and by-product workers are potentially exposed to coke oven emissions (COE), which contain hundreds of chemicals and are primarily composed of polycyclic aromatic hydrocarbons (PAH) and volatile organic compounds. Some of these compounds are hepatotoxins. The objective of this study was to examine the relationship between work in coke oven and by-product plants and serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), the most commonly performed liver-function tests. The exposed group was composed of current workers who had been employed at least 3 months in the two coke-operation work areas, including one coke oven plant and one by-product plant (Area I: n = 117; Area II: n = 96) of a large steel company in Taiwan. Control subjects (Area III: n = 131), not visiting either coke-operation area in the last 3 months, were collected from the administrative and nonproduction areas in the same company. PAH exposure, as a surrogate of COE, was measured monthly by PM-10 size-selective high-volume-area air samplers in or around these three areas between June and December 1990, as well as between November 1992 and June 1993. The mean total respiratory particulate PAH exposure levels (< 10 microns) between November 1992 and June 1993 in Area I, II, and III were 6.8 x 10(3), 2.1 x 10(3), and 6.5 x 10(1) ng/m3, respectively. AST, ALT, and hepatitis B surface antigen tests were performed in 1994. Workers who showed either AST or ALT levels greater than reference levels (abnormal > 25 IU/L) were regarded as showing "elevated liver enzyme levels." Workers in Area I had AST levels that were 17% higher (95% confidence interval [CI], 3% to 32%]) and ALT levels that were 35% higher (95% CI, 10% to 65%)] than those in Area III after controlling for appropriate confounders. The adjusted odds ratio (Area I vs Area III) for elevated liver enzymes was 4.4 (95% CI, 1.5 to 13.4). In addition, coke oven (n = 91) and by-product workers (n = 26) from Area I had ALT levels 37% and 45% higher, respectively, compared with control subjects from Area III, after adjusting for appropriate confounders. Similar effects are also seen for AST. Workers in Area II had slightly, but not significantly, elevated AST and ALT levels. These results indicate that workers most heavily exposed to COE exhibit elevated aminotransferase levels.