HCV Infection Alters Salivary Gland Histology and Saliva Composition.

Hepatitis C virus (HCV) infection is the most common blood-borne chronic infection in the United States. Chronic lymphocytic sialadenitis and sicca syndrome have been reported in chronic HCV infection. Up to 55% of these patients may have xerostomia; the mechanisms of the xerostomia and salivary gland (SG) hypofunction remain controversial. The objectives of this project are to establish if xerostomia associates with SG and HCV infection and to characterize the structural changes in SG and saliva composition. Eighteen HCV-infected patients with xerostomia were evaluated for SG dysfunction; 6 of these patients (patients 1-6) were further evaluated for SG histopathological changes and changes in saliva composition. The techniques used include clinical and laboratory assessment, SG ultrasonography, histological evaluation, sialochemical and proteomics analysis, and RNA in situ hybridization. All the HCV patients had low saliva flow, chronic sialadenitis, and SG fibrosis and lacked Sjögren syndrome (SS) characteristic autoantibodies. Further evaluation of a subgroup of 6 HCV patients (patients 1-6) demonstrated diffuse lymphocytic infiltrates that are predominantly CD8+ T cells with a significant increase in the number of inflammatory cells. Alcian Blue/periodic acid-Schiff staining showed significant changes in the ratio and intensity of the acinar secretory units of the HCV patients' minor SG. The submandibular glands showed significant ultrasonographic abnormalities in the parenchyma relative to the parotid glands. Significant changes were also observed in the concentration of sodium and mucin 5b. Although no significant correlation was observed between the lymphocytic infiltrates and the years of HCV chronic infection, a positive correlation was observed between HCV RNA-positive epithelial cells and the years of HCV infection. Consistent with the low saliva flow and xerostomia, patients showed changes in several markers of SG acinar and ductal function. Changes in the composition of the saliva suggest that HCV infection can cause xerostomia by mechanisms distinct from SS.

Relationship Between Neuromyelitis Optica Spectrum Disorder and Sjögren's Syndrome: Central Nervous System Extraglandular Disease or Unrelated, Co-Occurring Autoimmunity?

OBJECTIVE: Sjögren's syndrome (SS) patients may be affected by the neuromyelitis optica spectrum disorder (NMOSD), a severe demyelinating syndrome associated with anti-aquaporin 4 antibodies (anti-AQP-4 antibodies). The relationship between SS and NMOSD has been a sustained focus of investigation. Among SS patients, anti-AQP-4 antibodies have been detected exclusively in those with NMOSD. It has therefore been speculated that NMOSD is not a neurologic complication of SS. However, such studies evaluated small numbers of SS patients, often mixed with other inflammatory disorders. METHODS: We compared frequencies of anti-AQP-4 and SS-associated antibodies in 109 SS patients, including 11 with NMOSD, 8 with non-NMOSD demyelinating syndromes, and 90 without demyelinating syndromes. RESULTS: When assessed using a fluorescence-activated cell sorting (FACS) assay, anti-AQP-4 antibodies were seen exclusively in those SS patients with NMOSD (72.7%), but not in SS patients without NMOSD (P < 0.01). In contrast, anti-Ro 52, anti-Ro 60, and other autoantibodies were not more prevalent in SS patients with NMOSD versus those without. Anti-AQP-4 antibodies were detected more frequently among NMOSD patients by FACS assay than with a commercial immunohistochemical assay (72.7% versus 54.5%), despite assessment after a more prolonged period of immunosuppressive therapy (median 38 months versus 5 months; P < 0.01). CONCLUSION: The syndrome-specificity of anti-AQP-4 antibodies, along with an otherwise similar antibody profile in SS NMOSD patients, indicates that NMOSD is not a direct central nervous system manifestation of SS. Anti-AQP-4 antibodies can persist and be refractory to prolonged immunosuppressive therapy.

Eosinophilic sialodochitis: redefinition of 'allergic parotitis' and 'sialodochitis fibrinosa'.

Sialodochitis fibrinosa and allergic parotitis have described rare patients with recurrent salivary gland swelling and mucus plugs, often with atopy. We have evaluated three patients with atopic disease, recurrent salivary gland swelling, and an eosinophilic sialodochitis. Two had eosinophil-rich mucus plugs. Fifty-six additional cases were identified in a medical literature database search, each defined by recurrent salivary gland swelling associated with eosinophil-rich mucus plugs or sialodochitis with periductal eosinophilic infiltration. The majority (78%) were reported from Japan. Females were predominantly affected (F:M = 2.3) with a median age of 47 years at evaluation. The parotid and submandibular glands were involved, respectively, in 71% and 46%. Allergic symptoms were present in 66%, atopic disease in 63% of those with reported allergy testing, and blood eosinophilia in 71%. Contrast sialography and other imaging modalities documented ductal dilatation in 82%. Treatments included anti-allergic medications (58%), systemic glucocorticoids (25%), duct cannulation with irrigation, steroid injection, and/or duct dilatation (36%), and glandular resection (19%). We recommend the diagnosis 'eosinophilic sialodochitis' be applied to patients who meet this case definition. The disease is a unique cause of chronic recurrent salivary gland swelling. Its likely allergic etiology may be amenable to current or future biologic therapies.

American College of Rheumatology classification criteria for Sjögren's syndrome: a data-driven, expert consensus approach in the Sjögren's International Collaborative Clinical Alliance cohort.

OBJECTIVE: We propose new classification criteria for Sjögren's syndrome (SS), which are needed considering the emergence of biologic agents as potential treatments and their associated comorbidity. These criteria target individuals with signs/symptoms suggestive of SS. METHODS: Criteria are based on expert opinion elicited using the nominal group technique and analyses of data from the Sjögren's International Collaborative Clinical Alliance. Preliminary criteria validation included comparisons with classifications based on the American­European Consensus Group (AECG) criteria, a model-based "gold standard"obtained from latent class analysis (LCA) of data from a range of diagnostic tests, and a comparison with cases and controls collected from sources external to the population used for criteria development. RESULTS: Validation results indicate high levels of sensitivity and specificity for the criteria. Case definition requires at least 2 of the following 3: 1) positive serum anti-SSA and/or anti-SSB or (positive rheumatoid factor and antinuclear antibody titer >1:320), 2) ocular staining score >3, or 3) presence of focal lymphocytic sialadenitis with a focus score >1 focus/4 mm2 in labial salivary gland biopsy samples. Observed agreement with the AECG criteria is high when these are applied using all objective tests. However, AECG classification based on allowable substitutions of symptoms for objective tests results in poor agreement with the proposed and LCA-derived classifications. CONCLUSION: These classification criteria developed from registry data collected using standardized measures are based on objective tests. Validation indicates improved classification performance relative to existing alternatives, making them more suitable for application in situations where misclassification may present health risks.

Acute myeloid leukemia in the setting of low dose weekly methotrexate therapy for rheumatoid arthritis.

Methotrexate is in widespread use as second-line therapy for rheumatoid arthritis. Treatment with methotrexate in this and other settings has not been associated with the development of therapy-related leukemias. Four patients with rheumatoid arthritis are reported who developed acute myeloid leukemia (AML) while receiving low dose weekly methotrexate therapy in the absence of previous or concomitant treatment with known leukemogenic agents. AML in these four patients was of different morphologic subtypes and was associated with heterogeneous cytogenetic abnormalities, cell surface marker expression and multidrug resistance protein expression. None of the recognized features of therapy-related leukemia were present in these four nor in five previously-reported patients. It is likely that the occurrence of AML in patients with rheumatoid arthritis in the setting of methotrexate therapy represents the coincidence of these two diseases, and does not reflect a causal relationship.

Reversible posterior leukoencephalopathy syndrome in systemic lupus erythematosus.

Reversible posterior leukoencephalopathy syndrome (RPLS) is an acute form of cerebrovascular injury that has been described recently in the setting of uncontrolled hypertension, puerperal eclampsia, or treatment with certain immunosuppressive drugs, including cyclosporine. It is reversible if treated promptly. Two patients with systemic lupus erythematosus (SLE), renal failure, and uncontrolled hypertension developed acute cerebrovascular symptoms; one had seizures and the other had headache and blurred vision. Both patients showed abnormal predominantly posterior lobe findings on neuroimaging films. The patients' symptoms and imaging abnormalities resolved completely with prompt correction of their hypertension and concomitant treatment with corticosteroids. RPLS should be recognized in SLE patients with uncontrolled hypertension and renal failure who present with headaches, seizures, cortical blindness, and other visual abnormalities. Prompt treatment with control of hypertension and withdrawal of precipitating drugs may be most important and can prevent permanent neurologic damage.

Lipoxygenase mRNA in cultured human epidermal and oral keratinocytes.

Although 15-lipoxygenase has not been purified from cultured human keratinocytes nor has cDNA coding for the protein been isolated from this source, this enzyme activity is implied by the finding of its stereospecific product in in vitro experiments. Based on two primer pairs derived from human reticulocyte 15-lipoxygenase cDNA, we detected approximately 260 bp and approximately 370 bp cDNA fragments that were indistinguishable by gel electrophoresis and Southern hybridization from those derived from reticulocyte 15-lipoxygenase cDNA. The approximately 260 bp polymerase chain reaction (PCR) fragment from a keratinocyte plasmid cDNA library was cloned and determined, by sequencing, to contain 262 bp that were 100% identical to the corresponding reticulocyte 15-lipoxygenase cDNA. These two reticulocyte-type 15-lipoxygenase PCR fragments were also detected from oral keratinocytes. Using platelet-type 12-lipoxygenase cDNA primers, we derived a 264 bp cDNA fragment from keratinocyte mRNA. By sequence analysis, this fragment was determined to be 99.6% identical to that from platelet-type 12-lipoxygenase cDNA. The same fragment was also observed from two amplified keratinocyte cDNA libraries, and from oral keratinocyte mRNA. This is the first demonstration of reticulocyte-type 15-lipoxygenase cDNA derived from the mRNA of cultured human keratinocytes.

Epidermal fatty acid oxygenases are activated in non-psoriatic dermatoses.

The extent of epidermal fatty acid oxygenase activation in non-psoriatic dermatoses and the nature of these oxygenases are not known. The monohydroxylated fatty acid derivatives produced in vivo and trapped in skin scales or produced in vitro by oxygenases preserved in scales were analyzed by high performance liquid chromatography in 10 patients with non-psoriatic dermatoses. Evidence for 15-lipoxygenase activation included the finding of 15(S)-hydroxyeicosatetraenoic acid (HETE) in scales from seven patients and the production of 15(S)-[14C]HETE and 13(S)-[14C]hydroxyoctadecadienoic acid (HODE) during scale incubations, respectively, with [14C]arachidonic and [14C]linoleic acid. Evidence for the activation of an arachidonic acid 12(R)-oxygenase included the finding of 12(R)-HETE in scales from eight patients and the production of 12(R)-[14C]HETE during scale incubations with [14C]arachidonic acid. 13-HODE was the predominant fatty acid derivative present in scale extracts; its lack of enantiopurity (mean S/R = 3.1) and the substantial formation of 9-HODE (mean S/R = 0.6; 9/13-HODE = 0.43) suggest its derivation from 15-lipoxygenase and a second oxygenase. The levels of 15(S)-HETE and 12(R)-HETE had a 125- to 144-fold range and were highest in scales from a patient with erythroderma and in three psoriatic scale samples similarly analyzed. These findings indicate that 15-lipoxygenase, most likely of keratinocyte origin, and an arachidonic acid 12(R)oxygenase of unknown type and cell origin are activated in diverse dermatoses.

Hypocomplementemic urticarial vasculitis syndrome. Clinical and serologic findings in 18 patients.

We identify and describe clinical findings in hypocomplementemic urticarial vasculitis syndrome (HUVS), an uncommon to rare illness related to systemic lupus erythematosus (SLE). A patient with recurrent, idiopathic urticaria-like lesions was diagnosed as having HUVS if a lesional biopsy showed leukocytoclastic vasculitis, the serum C1q was markedly decreased, and antibody to C1q was detected in the patient's serum. The clinical characteristics, serologic findings, and outcome of patients who met these criteria were determined from prospective and retrospective data, including hospital and office records, patient interviews, previously banked serum samples, and freshly drawn sera. Eighteen patients with HUVS were identified, and high incidences of angioedema, ocular inflammation, glomerulonephritis, and obstructive pulmonary disease were found. Renal and lung biopsies showed mesangial or membranoproliferative glomerulonephritis and severe pulmonary emphysema without vasculitis. Pulmonary function was measured in 17 patients, 11 of whom had dyspnea. All dyspneic patients had moderate to severe airflow obstruction, which progressed in all 11 and subsequently improved in only 1. Six of these 11 patients died of respiratory failure, 1 underwent lung transplantation, and 3 of the remaining 4 have moderately severe to life-threatening respiratory insufficiency. Treatment did not appear to alter the progression of obstructive lung disease. In contrast, renal insufficiency improved with treatment in 2 of 2 patients. Angioedema, ocular inflammation, obstructive lung disease, and glomerulonephritis appear to be common in HUVS, and lung disease causes substantial morbidity and mortality. The pathogenesis of HUVS may involve humoral autoimmunity, although it is not clear how autoimmunity would participate in development of obstructive lung disease. Cigarette smoking appears to be a risk factor for fatal lung disease in HUVS. All patients with HUVS should be made aware of this possibility and should be advised, encouraged, and helped to avoid tobacco smoke.

Fatty acid oxygenase activity of human hair roots.

The extent to which fatty acid oxygenases are activated in the normal epidermis is not known. Characterization of the regio- and stereospecificity of the monohydroxylated derivatives of arachidonic and linoleic acid produced by human hair roots is needed to define the enzymatic origin of these compounds and to define a possible role for fatty acid oxygenases in growth, differentiation, and pathology of human hair. Hair roots epilated from normal human volunteers were incubated with radiolabeled arachidonic acid or linoleic acid and the monohydroxylated derivatives produced in vitro were characterized. Incubation of hair roots with 14C]arachidonic acid resulted in the production of 15(S)-[14C]hydroxyeicosatetraenoic acid and 12(S,R)-[14C]hydroxyeicosatetraenoic acid (mean S/R ratio, 2.5). 13(S)-[14C]hydroxyoctadecadienoic acid was the principal product of incubations with [14C]linoleic acid. No radiolabeled products were derived from incubations with heat-denatured hair roots. The fatty acid oxygenase activity of anagen hair roots was inhibited by nordihydroguaiaretic acid and was greatest in the hair root bulb. The strict S-stereospecificity and the regiospecificity of the n-6 oxygenase are strong evidence for the presence of a 15-lipoxygenase in human hair roots, similar to that identified in cultured human keratinocytes. The stereospecificity of the 12-HETE produced by human hair roots is not compatible with the sole action of 12-lipoxygenase.

Cyclooxygenase activity of cultured human mesothelial cells.

The fatty acid oxygenase activity of mesothelial cells and its role in inflammatory and neoplastic diseases of the mesothelium have not been defined. Techniques permitting in vitro cultivation of human mesothelial cells shed into serous cavities have permitted analysis of their specific metabolic capacities. The principal products of incubations of cultured human mesothelial cells with polyunsaturated fatty acids were analyzed using high performance liquid chromatography on reversed-, straight-, and chiral-phase columns and gas-liquid chromatography/mass spectrometry. The products included 6-keto-PGF1 alpha, 15-hydroxyeicosatetraenoic acid (S/R = 3.5), 11-hydroxyeicosatetraenoic acid, and 12-hydroxyheptadecatrienoic acid from arachidonic acid; 9- and 13-hydroxyoctadecadienoic acids (molar ratio of 9/13-hydroxyoctadecadienoic acids = 3.5, S/R ratios = 0.3 and 2.8, respectively) from linoleic acid; and 12-hydroxyheptadecadienoic acid from homo-gamma-linolenic acid. These products are indicative of a cyclooxygenase whose activation in vivo may play a significant role in serosal cavity pathology.

Lipoxygenase products in inflammatory synovial fluids and other exudates.

Forty six synovial fluid samples from 42 patients with inflammatory joint disease were analysed by reversed phase high performance liquid chromatography to determine 5-lipoxygenase products, specifically dihydroxyeicosatetraenoic acids (diHETEs). Twenty eight per cent of the fluids which were assayed had one or more products of 5-lipoxygenase activation. Seven fluids contained leukotriene B4 (0.1-28.1 ng/ml); three fluids had low concentrations of 20 carboxy/hydroxy-leukotriene B4 (0.01-0.05 ng/ml); three samples had leukotriene B4 isomers (1.5-2.4 ng/ml); and four fluids contained 5,15-diHETE (2.3-16.4 ng/ml). There was a poor correlation between synovial fluid white blood cell counts and evidence of 5-lipoxygenase activation. Several fluids contained unidentified compounds with spectra similar in shape to that of trienes, but the lambda max values of these unidentified compounds were different from those of known leukotrienes. A septic peritoneal exudate and a septic pleural fluid had concentrations of leukotriene B4 and leukotriene B4 isomers and metabolites in a range similar to those found in synovial fluids.

Marked cerebrospinal fluid pleocytosis in systemic lupus erythematosus related cerebral ischemia.

Pleocytosis of the cerebrospinal fluid (CSF) may accompany central nervous system lesions that occur as a result of systemic lupus erythematosus (SLE); however, the number of CSF white blood cells is usually less than 50/mm3 and the predominant cell is the lymphocyte. A young woman with SLE had 2 acute episodes of hemorrhagic cerebral ischemia, each of which was associated with a neutrophilic CSF pleocytosis (white blood count 480-2250/mm3). This type of meningeal reaction may have been related to the proximity of the cerebral lesions to the ventricles, a phenomenon previously described in non SLE related cerebral infarcts.

Cytotoxicity of fatty acid oxygenase activation in rat basophilic leukemia cells.

Apart from the generation of potent inflammatory mediators, the effects of fatty acid oxygenase activation, per se, on the host cell have not been well-delineated. Fatty acid oxygenases were activated in rat basophilic leukemia cells (RBL-1) by incubating them for 2-4 hr with 33-300 microM of arachidonic acid (AA) or linoleic acid (LA). As a control, the cells were incubated with one of two analogs of these fatty acids which are not oxygenase substrates: eicosatetraynoic acid or linoelaidic acid. Effects of oxygenase activation on cell viability were monitored by an assay for mitochondrial function. Cytotoxicity occurred in incubations with exogenous AA or LA in direct proportion to the substrate concentration but was not found in the control incubations or in incubations with the principal monohydroxylated AA products, 5-, 15-, and 12-HETE. Nordihydroguaiaretic acid (80 microM) and alpha-tocopherol (100 microM) significantly decreased the cell death observed during incubations with AA or LA. It is concluded that extensive oxygenase activation can result in cell death from intermediates produced proximal to the stable monohydroxylated derivatives.

In vivo activation of an omega-6 oxygenase in human skin.

To test the hypothesis that an epidermal fatty acid oxygenase is activated in vivo under physiologic conditions, surface lipids from normal human skin were analyzed for oxygenase products. With high-performance liquid chromatography on reversed-phase and straight-phase chiral columns and gas-liquid chromatography/mass spectrometry, these lipids were found to contain free 13-hydroxyoctadeca-9Z,11E-dienoic acid and 9-hydroxyoctadeca-10E,12Z-dienoic acid. The 13-hydroxyoctadecadienoic acid was present as a stereoisomeric mixture, with an average S/R ratio of 2.2, and exceeded the concentration of 9-hydroxyoctadecadienoic acid by a factor of 2. These observations and others indicate that the 13-hydroxyoctadecadienoic acid was derived mostly from an omega-6 oxygenase (probably 15-lipoxygenase) which is activated in vivo in normal skin.

Stereospecificity of the hydroxyeicosatetraenoic and hydroxyoctadecadienoic acids produced by cultured bovine endothelial cells.

Characterization of the stereospecificity of the derivatives of arachidonic acid and linoleic acid produced by endothelial cells is needed to define the enzymatic origin of these compounds and their role in vascular physiology. In studies utilizing two bovine endothelial cell lines (CPAE and AG04762), both free 15-hydroxyeicosatetraenoic acid (15-HETE) and 11-hydroxyeicosatetraenoic acid (11-HETE) were generated during incubations with exogenous arachidonic acid and both free 9-hydroxyoctadecadienoic acid (9-HODE) and 13-hydroxyoctadecadienoic acid (13-HODE) were generated during incubations with exogenous linoleic acid. Esterification of 15-HETE, 9-HODE and 13-HODE during these incubations was demonstrated. The analyses included reversed-phase high performance liquid chromatography of the free acid and its methyl ester and chiral separation of the methyl ester on straight phase chiral columns. The ratio of 9-HODE/13-HODE averaged 2.7 in the chromatographic analyses of the extracts of the incubations with linoleic acid. The combined production of 13-HODE and 9-HODE from linoleic acid was four times greater than that of 15-HETE and 11-HETE from arachidonic acid. With regard to the products of the CPAE endothelial cell line, the S/R ratio of the stereoisomers averaged 1.5 for free 15-HETE, 5.7 for free 13-HODE and 0.2 for free 9-HODE. The 11-HETE had strict (R) stereospecificity. The products from the AG04762 endothelial cell line had similar stereochemistry. All these stereochemical findings point to the activity of a cyclooxygenase rather than that of a lipoxygenase.

Saturability of esterification pathways of major monohydroxyeicosatetraenoic acids in rat basophilic leukemia cells.

The principal monohydroxyeicosatetraenoic acids (HETEs), 5-, 12-, and 15-HETE, which can be produced by rat basophilic leukemia (RBL-1) cells, are also esterified by these cells. Exogenously added 5-, 12-, and 15-HETE were rapidly incorporated as esters in RBL cells, reaching plateau levels within 25 min. In incubations in culture medium with protein added, all three HETEs were essentially completely metabolized within 24 h. 5-HETE was esterified more rapidly and to a greater extent than 12-HETE or 15-HETE when these were incubated together with RBL cells, indicating some degree of selectivity in the esterification pathways. When arachidonic acid (AA) was incubated in increasing concentrations with constant concentrations of 15-HETE and RBL cells, the free 15-HETE concentration increased and esterified 15-HETE concentration decreased markedly at AA: 15-HETE molar ratios above 9. 15-HETE esterification in RBL cells was also markedly inhibited by the polyunsaturated fatty acids, eicosatetraynoic and eicosapentanoic acids, but not by oleic or linoleic acids. In separate experiments with unlabeled and radiolabeled substrates, the extent of incorporation of esterified HETE in RBL cells decreased at higher concentrations of 15-HETE and AA, which showed that the pathway was saturable. The shapes of the curves for these fatty acid inhibitors suggest a concentration-dependent two-compartment pathway of esterification. These data indicate that the HETEs and other 20 carbon fatty acid substrates probably compete for activity of a specific arachidonyl-CoA synthetase, which is the first and rate-limiting step for esterification of arachidonic acid by many human cells. Esterified 15-HETE was found to be predominantly in the phosphatidylethanolamine fraction of RBL cell lipids.

Stereospecificity of the products of the fatty acid oxygenases derived from psoriatic scales.

The principal in vivo oxygenase products of arachidonic acid and linoleic acid in psoriatic skin scales are 12-hydroxyeicosatetraenoic acid (R/S ratio = 5.7), 13-hydroxyoctadecadienoic acid (S/R = 1.9), and 9-hydroxyoctadecadienoic acid (R/S = 2.4). Definition of the enzymatic origin of these fatty acid derivatives is an important step in assessing their possible role in the pathogenesis of psoriasis. Psoriatic skin scales were incubated with radiolabeled arachidonic acid and linoleic acid and the monohydroxylated derivatives produced in vitro were characterized. The products of incubation with [3H]arachidonic acid were an enantiopure 15(S)-[3H]hydroxyeicosatetraenoic acid and a nonracemic mixture of the 12-[3H]hydroxyeicosatetraenoic acid steroisomers (R/S ratio = 4.5). An enantiopure 13(S)-[14C]hydroxyoctadecadienoic acid was produced from [14C]linoleic acid. No radiolabeled products were derived from incubations with heat-denatured scales. These results provide evidence for two distinct oxygenase activities that are preserved in psoriatic skin scales. One is that of an omega-6 oxygenase with strict (S) stereospecificity, consistent with the activity of a lipoxygenase. This enzyme activity appears to be similar to that of the 15-lipoxygenase which has been described in cultured human keratinocytes. The second activity is that of an arachidonic acid 12(R)-oxygenase that has not been observed in normal human epidermis but which appears to be expressed in psoriatic epidermis.

Staphylococcal infection of the subacromial/subdeltoid bursa.

A patient with a Staphylococcus aureus infection of the subacromial/subdeltoid bursa is described. Instillation of radiocontrast dye into the purulent cavity provided evidence that the infection was localized to the subacromial/subdeltoid bursa. The use of bursography/arthrography to define the site and extent of shoulder infections may help to determine the optimal duration of antibiotic therapy and the prognosis for cartilage and/or bone destruction.

Characterization of the chirality of the monohydroxy-eicosatetraenoic acids produced by rat basophilic leukemia cells.

Incubation of rat basophilic leukemia cells with exogenous arachidonic acid and permeabilizing concentrations of ethanol resulted in the production of 5-, 12-, and 15-hydroxyeicosatetraenoic acids. With chiral phase high performance liquid chromatography, it was demonstrated that the 5-hydroxyeicosatetraenoic acid had strict (S) stereospecificity while contrary to expectation, the 12- and the 15-hydroxyeicosatetraenoic acids were non-racemic mixtures of the stereoisomers with the S/R ratios averaging 8.6 and 2.2, respectively. If the strict (S) stereospecificity of mammalian lipoxygenases holds true, these results suggest that the 15- and 12-hydroxyeicosatetraenoic acids may be derived from non-lipoxygenase sources. Examination of the chirality of the oxygenase products of unsaturated fatty acids may be of value in defining the enzymes which are activated in vivo in pathological states.