Indirect Immunofluorescence Examination Research Articles

CHALLENGING NEGLECT OF TEGUMENTARY LEISHMANIASIS: HEALTH PROMOTION IN AN ENDEMIC AREA IN SOUTHERN BRAZIL

This study aimed to verify the epidemiological profile of tegumentary leishmaniasis (TL) in an endemic area in Southern Brazil and to develop health education activities with the local population to prevent new cases. This was a prospective study conducted with residents of the Borba Gato district, Maringá-Paraná, from March 2018 to June 2023. A questionnaire was applied to the participants to investigate the previous knowledge about TL and exposure to risk factors. Laboratory tests were performed to actively search for new cases of TL in the neighborhood. A total of 61 patients underwent indirect immunofluorescence (IFI) examination. Eight of them had a history of the disease, of which three continued to have positive titers on the test (IFI > 40) even after years of treatment completion. A new case of the disease was confirmed during the development of the study and progressed to clinical cure following administration of meglumine antimoniate 20mg/kg/day. Distribution of educational leaflets and lecture cycles with the population and health professionals of the neighborhood were developed to elucidate them regarding the form of transmission and preventive measures against TL. Health surveillance actions are necessary to control TL in endemic areas and promote human and animal health.

Clinical, Molecular, and Histopathological Aspect of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune liver disease which tends to be chronic and progressive in nature that is marked by the presence of cholangitis and small size biliary duct destruction which may cause cirrhosis or even liver failure. PBC incidence increases because PBC can now be diagnosed earlier and is due to the increasing survival rate of PBC patients. Diagnosis of PBC can be confirmed in asymptomatic state if in the indirect immunofluorescence (IIF) examination revealed AMA positive, and there is an abnormal liver function. Etiopathogenesis of PBC is multifactorial which involves genetic and environmental factors. Genetic factors which contribute to the incidence of PBC are HLA and non-HLA genes, while in the environmental factors, the triggering factors of PBC are bacterial infection and xenobiotic. Interaction of these factors causes the development of E2 subunit pyruvate dehydrogenase complex (PDC-E2) and antimitochondrial antibody (AMA) as the causing autoantigen of biliary duct desctruction in PBC, mediated by the immune system. PBC stage is divided into minimal, mild, moderate and severe. Ursodeoxycholic acid (UDCA) is the first line therapy for PBC, while obeticholic acid (OCA) and fibrate is used as the second line. Liver transplantation is the definitive therapy for PBC where disease progresses into the advanced stage, although the patients have received medical treatment.

Anti-centriole antibody: An infectious or autoimmune process?

Anti-centriolar pattern of staining by indirect immunofluorescence (IIF) on human epithelial type 2 (Hep2) cells is rarely observed, mostly in association with scleroderma and scleroderma-like connective tissue disorders. This paper describes four patients with anti-centriole antibody positivity along with a review of the available literature. In this retrospective study, a total of four cases whose serum showed the centriolar pattern on Hep2 cell lines during IIF examination were reviewed. The presence of anti-centriole antibody in the serum should herald the diagnosis of scleroderma spectrum; Raynaud's phenomenon and pulmonary arterial hypertension should be specifically looked for. In the absence of features of autoimmunity, patients should be screened for Mycoplasma infection.

Growth of Different Infectious Bursal Disease Virus Strains in Cell Lines from Origin of Lymphoid Leukosis Tumors

Growth and propagation of infectious bursal disease virus (IBDV) in chicken embryo is time consuming and costly, and an appropriate serological test is required to detect and identify IBDV strains, therefore, a suitable cell lines in which different IBDV strains can grow well has been needed. The aim of the present work was to study the growth of different IBDV strains in cell lines from lymphoid leukosis tumors using histopathological staining, indirect immunofluorescence, immunohistochemistry and transmission electron microscopic examination. In conclusion, cell lines from origin of lymphoid leukosis tumors; LSCC-BK3 and LSCC-CU10 are suitable for growth and propagation of different IBDV strains. IBDV strains resulted into histopathological lesions of variable severity differ according to the patho-type of IBDV and time after virus inoculation. Indirect immunofluorescent test could be used for detection and differentiation of IBDV strains inoculated into cell lines from origin of lymphoid leukosis tumors. Trials of immunohistochemistry technique for detection of different IBDV strains in cell lines, were unsuccessful. Using transmission electron microscopy, IBDV particles could be detected in all infected cell lines.

A Case of Concurrent MPO-/PR3-Negative ANCA-Associated Glomerulonephritis and Membranous Glomerulopathy.

We report a case in which antineutrophil cytoplasmic antibody- (ANCA-) associated glomerulonephritis and membranous glomerulopathy (MGN) were detected concurrently. The patient showed rapidly progressive renal deterioration. A renal biopsy showed crescentic glomerulonephritis, together with marked thickening and spike and bubbling formations in the glomerular basement membranes. Indirect immunofluorescence examination of the patient's neutrophils showed a perinuclear pattern. Enzyme-linked immunosorbent assays revealed that the ANCA in this case did not target myeloperoxidase (MPO) or proteinase 3 (PR3) but bactericidal-/permeability-increasing protein, elastase, and lysosome. The relationship between these two etiologically distinct entities, MPO-/PR3-negative ANCA-associated glomerulonephritis and MGN, remains unclear.

Concomitant Psoriasis and Bullous Pemphigoid – a Case Report / Udružena pojava psorijaze i buloznog pemfigoida – prikaz slučaja

Abstract Concomitant occurrence of psoriasis and bullous pemphigoid was described in less than 100 cases in the literature. The co-occurrence affects the treatment approach of patients. We present a case of a 58-year-old man with psoriasis presenting with erythematous plaques, tense bullae, erosions and fever up to 39°C. Direct and indirect immunofluorescence and histopathological examination confirmed the diagnosis of bullous pemphigoid. In our case, bullous eruptions were successfully treated with oral methylprednisolone and dapsone, and psoriasis with narrowband ultraviolet B phototherapy and acitretin. In conclusion, the etiopathogenesis of the coexistence of these two entities remains unknown, but it may be related to relatively high incidence of psoriasis and bullous pemphigoid, respectively. Both conditions are immunologically mediated and combined immunosuppressive regimens, directed at cellular and humoral immune responses, usually result in clinical improvement.

Occurrence and cytological mechanism of numerically unreduced pollen in diploid Populus euphratica

AbstractUnreduced gametes are the driving force for the polyploidizaiton of plants in nature, and are also an important tool for breeding of triploid individuals. The final heterozygosity of a 2n pollen grain depends on the cytological mechanism behind 2n pollen formation. In this study, meiotic abnormalities were analysed using fluorescent chromosome staining and indirect immunofluorescence during the microsporogenesis of 18 genotypes of diploid P. euphratica Oliv. (2n = 2x = 38). Among the 18 genotypes, 16 genotypes produce 2n pollen and two genotypes produce only normal n pollen. In all 2n pollen producers, we found that the first meiotic division was normal but that the second division was characterized by frequent abnormal spindle orientation (parallel, tripolar, and fused spindles) and premature cytokinesis. The parallel, fused spindles and premature cytokinesis were considered to be leading dyad formation, and tripolar spindles seemed to be causing triad formation at the tetrad stage. There was a higher frequency of parallel spindles than other spindle forms, but no significant correlations between parallel spindles and dyads were observed. However, a significant association (r = 0.68, P < 0.05) between the tripolar spindles and dyads was found. In some Microspore mother cells (MMCs), an indirect immunofluorescence examination of meiosis II revealed that the parallel spindles led to the gathering of one or two non-sister groups of chromosomes, causing an incorporation of RMSs from two daughter nuclei. Therefore, the incorporated RMSs established two nuclear cytoplasmic domains for the control of division plane, resulting in either triad or dyad formation.

Generation of a Monoclonal Antibody to S1 Protein of Porcine Epidemic Diarrhea Virus

Gene encoding the N-terminal half of spike protein (S1) of porcine epidemic diarrhea virus (PEDV) was cloned and expressed as a recombinant protein in Escherichia coli BL21 (DE3). Then, female BALB/c mice were immunized with the purified recombinant S1 protein (rS1), and a monoclonal antibody (MAb designated as 5E12) against the rS1 protein was achieved by hybridoma technique. MAb 5E12 not only reacted with rS1 protein indirect ELISA and Western blot, but also recognized PEDV transiently expressed in Vero E6 cells in indirect immunofluorescence examinations. This work suggests that 5E12 would be a useful tool as a specific diagnostic reagent for detecting PEDV S protein.

Paraneoplastic pemphigus: A retrospective case series in a referral center in northern Taiwan

Paraneoplastic pemphigus (PNP) is a rare mucocutaneous disease with a high mortality rate. It is defined by polymorphic mucocutaneous manifestations, particular histological features, characteristic results of direct and indirect immunofluorescence examinations, presences of specific autoantibodies, and associations with underlying neoplasms. However, currently, there is no existing study regarding the characteristics of PNP patients in Taiwan. In this study, we report a case series and try to determine the specific presentations of PNP patients in Taiwan. PNP patients treated in a referral center in northern Taiwan from 1998 to 2012 were retrospectively recruited. The clinical manifestations, histopathological features, findings of direct and indirect immunofluorescence, results of immunoblotting, and all relevant clinical information were collected. Eleven patients were identified with an average age of 62 years. Polymorphic mucocutaneous manifestations were observed in almost all patients. The most common presentation was pemphigus-like lesions, followed by lichen planus-like lesions. All patients had recalcitrant oral mucosal lesions. Five and four patients had genital and eye involvements, respectively. The mostly associated neoplasm is Castleman’s disease, followed by malignant thymoma. Acantholysis is the mostly observed histological features, followed by lichenoid dermatitis and interface dermatitis. Depositions of immunoglobulins or complements on the surface of keratinocytes or along basement membrane zone were found in eight and seven patients, respectively. Respiratory symptoms presented in eight patients. Despite intensive treatments, seven patients expired. PNP in Taiwanese patients has a high association with Castleman’s disease or malignant thymoma. Complete laboratory examinations and thorough investigations for occult neoplasms are mandatory to establish a diagnosis in patients with clinical suspicions of PNP.

Dendritic Cells Are Central Coordinators of the Host Immune Response to Staphylococcus aureus Bloodstream Infection

Dendritic cells (DCs) play an important role in integration of the immune responses induced by pathogens. The purpose of this study was to determine the importance of DCs in host defense against Staphylococcus aureus bacteremia. Using a murine infection model, we demonstrated that DCs are rapidly recruited into infected tissue after intravenous inoculation with S. aureus. The recruited DCs were fully functional and in a more advanced stage of maturation than those isolated from uninfected mice. Depletion of DCs in CD11c-DTR transgenic mice resulted in substantial worsening of infection, as indicated by increased bacterial loads in kidneys and lungs, accelerated mortality, and more severe pathology. Furthermore, DC depletion completely abolished IL-12 production in response to infection. The beneficial effect afforded by DCs during S. aureus infection was not mediated by their contribution to direct bacterial killing, nor by increased neutrophil recruitment. Instead, neutrophil influx (along with expression of CXC chemokines) was significantly enhanced in infected tissue after depletion of DCs. We also found that the bactericidal capacity of the recruited neutrophils was significantly impaired in DC-depleted mice. More importantly, the detrimental effect of DC depletion was practically reversed by treatment with exogenous recombinant mouse IL-12. Our results demonstrated that DCs, probably through their production of IL-12, play an important role in coordinating the inflammatory response during S. aureus infection.

Immunofluorescence in dermatology

Direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) tests on skin biopsy are being done mostly in academic teaching hospitals. These tests provide a useful diagnostic aid to dermatologists. Immunohistology and serology can, in conjunction with histology, provide considerable help in delineation and diagnosis of various skin disorders as well as systemic diseases with skin involvement, e.g. systemic lupus erythematosus. Immunofluorescence (IF) studies have now become an invaluable supplement to clinical and histological examination in a variety of dermatological diseases. These skin diseases now include not only bullous and connective tissue disorders, vasculitides, and conditions such as lichen planus, but also the scaling dermatoses, notably psoriasis. In this review article, we share our experience of providing such a diagnostic facility for more than 30 years in a large tertiary care health center in North India and also help to outline the conditions, which can be diagnosed confidently, and others where IF can help in confirming a diagnosis or the immune component of the disease. The article also deals with handling of skin biopsy specimens and interpretation of biopsy findings on DIF and IIF examination.

Secreted glyceraldehyde-3-phosphate dehydrogenase as a broad spectrum vaccine candidate against microbial infection in aquaculture

Subcellullar localizations and cross-immunities of GAPDHs from six common pathogenic bacteria in aquaculture were investigated. Subcellullar localizations of GAPDHs of Edwardsiella tarda EIB202, Edwardsiella ictaluri ATCC33202, Aeromonas hydrophila LSA34, Vibrio anguillarum MVM425, Vibrio alginolyticus EPGS020401 and Vibrio harveyi VIB647 were analysed with Western blotting, indirect immunofluorescence and flow cytometry examinations. Immunoprotections of different recombinant GAPDHs against these pathogens were investigated with zebrafish model. Western blotting of subcellular extractions showed that all GAPDHs were secreted into extracellular medium and periplasmic space. In addition, GAPDHs were demonstrated to distribute in the outer membranes except MVM425 and VIB647. And, GAPDHs were confirmed to be present on the surface of these bacteria with indirect immunofluorescence and flow cytometry examinations. The remarkable cross-protective immunities of these recombinant GAPDHs were induced in zebrafish, and the relative protective survivals were almost over 60%. Localizations of GAPDHs from these pathogenic bacteria were similar to many other causative agents. And, GAPDHs could be important protective antigens and give remarkable cross-immunity against different pathogens. Recombinant GAPDH could be designed as a broad spectrum vaccine candidate against multiple microbial infections in aquaculture.

GAD antibodies associated neurological disorders: Incidence and phenotype distribution among neurological inflammatory diseases

We investigated the prevalence and the clinical association of high titer of antibodies against glutamic acid decarboxylase (hGADAb) among unselected patients with inflammatory/autoimmune disorders of the nervous system. By indirect immunofluorescence examination of samples from 1435 patients, we identified 7 cases (0.48%) with hGADAb. Although stiff-person plus syndrome was the commonest clinical accompaniment, most of the patients presented with a combination of different symptoms, including psychiatric disturbances and intestinal motility disorders. Diagnosis delay and chronic evolution were common findings. In two cases persistently high values of hGADAb over the years were observed. The rarity and the phenotype heterogeneity of hGADAb clinical association should not discourage clinicians from antibody screening, at least in selected cases, as an early immunotherapy can change the otherwise chronic progression of this complex disorder spectrum.

Establishment of a protocol for obtention of neuronal stem cells lineages from the dog olfactory epithelium

A morphological and cell culture study from nasal mucosa of dogs was performed in order to establish a protocol to obtain a cell population committed to neuronal lineage, as a proposal for the treatment of traumatic and degenerative lesions in these animals, so that in the future these results could be applied to the human species. Twelve mongrel dogs of 60-day aged pregnancy were collected from urban pound dogs in São Paulo. Tissue from cribriform ethmoidal lamina of the fetuses was collected at necropsy under sterile conditions around 1h to 2h postmortem by uterine sections and sections from the fetal regions described above. Isolated cells of this tissue were added in DMEM/F-12 medium under standard conditions of incubation (5% CO², >37ºC). Cell culture based on isolated cells from biopsies of the olfactory epithelium showed rapid growth when cultured for 24 hours, showing phase-bright sphere cells found floating around the fragments, attached on culture flasks. After 20 days, a specific type of cells, predominantly ellipsoids or fusiform cells was characterized in vitro. The indirect immunofluorescence examination showed cells expressing markers of neuronal precursors (GFAP, neurofilament, oligodendrocyte, and III â-tubulin). The cell proliferation index showed Ki67 immunostaining with a trend to label cell groups throughout the apical region, while PCNA immunostaining label predominantly cell groups lying above the basal lamina. The transmission electron microscopy from the olfactory epithelium of dogs revealed cells with electron-dense cytoplasm and preserving the same distribution as those of positive cell staining for PCNA. Metabolic activity was confirmed by presence of euchromatin in the greatest part of cells. All these aspects give subsidies to support the hypothesis about resident progenitor cells among the basal cells of the olfactory epithelium, committed to renewal of these cell populations, especially neurons.

Cytological characteristics of numerically unreduced pollen production in Populus tomentosa Carr.

Natural triploids of Populus tomentosa (2n = 3x = 57) are presumably the result of sexual polyploidization through the union of normal n female gametes and numerically unreduced (2n) male gametes. In our microscopic study of microspore mother cells (MMCs) of diploid P. tomentosa (2n = 2x = 38), we observed that the first meiotic division was normal but that the second division was characterized by frequent abnormal spindle orientation (parallel, tripolar, and fused spindles) and premature cytokinesis. The parallel, fused spindles and premature cytokinesis were considered to be leading dyad formation, and tripolar spindles seemed to be leading triad formation at the tetrad stage. There was a higher frequency of parallel spindles than other spindle forms, but there were no significant correlations between parallel spindles and dyads. An indirect immunofluorescence examination of meiosis II revealed that four tetragonally arranged nuclei were formed in MMCs with parallel spindles and that there were radial microtubules systems (RMSs) among these four nuclei, leading to the tetragonal tetrad. In some MMCs, however, the parallel spindles led to the gathering of one or two non-sister groups of chromosomes, causing an incorporation of RMSs from two daughter nuclei. Thus, the incorporated RMSs established three or two nuclear cytoplasmic domains for the control of division plane, resulting in either triad or dyad formation. These results provide new insights on the mechanism of parallel spindles leading to numerically unreduced pollen formation and on the selection and utilization of this type of pollen in polyploid breeding of P. tomentosa.

A case of epidermolysis bullosa acquisita with unusual clinical features

A 30-year-old woman developed epidermolysis bullosa acquisita (EBA) with unusual clinical features. Initially, only prurigo-like nodules were seen, which lasted for > 2 years and then blisters appeared. Eruptions resembling the rash in systemic lupus erythematosus were also seen on the face. Histopathological examination of a biopsy specimen revealed subepidermal blisters containing eosinophils and neutrophils. Direct immunofluorescence examination, indirect immunofluorescence examination using skin split with 1 mol/L sodium chloride, and immunoblotting analysis using extracts of normal human dermis gave results compatible with EBA. This case shows that EBA can present with nodular lesions as seen in pemphigoid nodularis or epidermolysis bullosa pruriginosa.

Non‐infectious ulcerating oral mucous membrane diseases

Non-infectious ulcerative oral mucous membrane diseases are difficult to separate at first glance: they can appear as aphthous, bullous, lichenoid, drug-induced or toxic-irritative reactions. The overall considerations of history, localization of lesions, clinical and histological features, as well as direct and indirect immunofluorescence examination are required for the correct diagnosis. Some disorders start preferably at the oral mucosa, like pemphigus vulgaris and Adamantiades-Behçet disease, while others, such as cicatricial pemphigoid and habitual aphthosis generally are confined to the mucous membranes. This overview summarizes clinical and diagnostic features, differential diagnoses and current therapeutic possibilities of non-infectious inflammatory stomatopathies, which possess a specific position among skin diseases in distinction to infectious or neoplastic oral ulcers. This group of diseases includes aphthous lesions, lichen planus mucosae, lupus erythematosus, disorders with intraepidermal or subepidermal formation of blisters including pemphigus, bullous pemphigoid, erythema multiforme and variants as well as allergic or toxic contact stomatitis.

Detection of anti-myeloperoxidase and anti-elastase antibodies in vasculitides and infections

Autoantibodies that produce a perinuclear pattern on indirect immunofluorescent examination of ethanol-fixed neutrophils (pANCA) are found in about half of all cases of microscopic polyarteritis. These antibodies are often directed against myeloperoxidase or elastase and we have developed sensitive reproducible ELISAs for their detection and study. Seven sera from 19 patients with microscopic polyarteritis or segmental necrotizing glomerulonephritis contained anti-myeloperoxidase or anti-elastase antibodies or both. In contrast, only one of 18 sera from patients with Wegener's granulomatosis, where the pattern of immunofluorescence is predominantly cytoplasmic, had anti-myeloperoxidase antibodies and no anti-elastase antibodies were detected. Using sera from patients with microscopic polyarteritis, both anti-myeloperoxidase and anti-elastase antibodies were demonstrated to be of high affinity. There was no immunoglobulin class, subclass or light chain restriction noted. Anti-myeloperoxidase and anti-elastase antibodies were also found occasionally in anti-glomerular basement membrane disease, mixed connective tissue disease, systemic lupus erythematosus, post-streptococcal glomerulonephritis and atypical pneumonia. In further studies these antibodies were not associated with other lung infections, although anti-elastase antibodies were noted in one of 14 sera positive for ASOT that were tested. Anti-myeloperoxidase antibodies were found more frequently than anti-elastase antibodies and these antibodies were occasionally present together. In addition some sera with pANCA had neither anti-myeloperoxidase nor anti-elastase antibodies. The target molecules in these cases remain unclear.

Diverse target antigens recognized by circulating antibodies in anti-neutrophil cytoplasm antibody-associated renal vasculitides

Antibodies that are directed against cytoplasmic constituents of neutrophils and monocytes (anti-neutrophil cytoplasm antibodies, ANCA) have been described in Wegener's granulomatosis, microscopic polyarteritis (MPA) and some cases of segmental necrotizing glomerulonephritis (SNGN). Other antibodies occasionally described in Wegener's granulomatosis and MPA include anti-nuclear antibodies (ANA) and anti-glomerular basement membrane (GBM) antibodies. We have studied the diversity of the corresponding antigens in ANCA-associated renal diseases. Sera from 46 patients with active histologically proven Wegener's granulomatosis, MPA and SNGN were tested for ANCA by indirect immunofluorescent examination of normal peripheral blood neutrophils. Thirty-four sera (74%) were positive; 16 were associated with diffuse cytoplasmic staining (cANCA) and 18 with perinuclear staining (pANCA). In addition, five demonstrated antineutrophil-specific nuclear staining (ANNA). On Western blotting of the neutrophil extract, five sera recognized a 29-kD molecule recently identified as neutrophil proteinase 3. Two sera with typical cANCA bound to molecules of 36, 38 and 116 kD and another to a molecule of 22 kD. The final serum associated with pANCA bound to a molecule of about 12 kD. Thirteen sera out of 46 (28%) tested in an ELISA contained anti-myeloperoxidase antibodies; 10 of these were associated with pANCA and two others with ANNA. Three sera of 17 (18%) tested contained anti-elastase antibodies; these also contained anti-myeloperoxidase antibodies and were associated with pANCA. However, eight sera with pANCA were negative for anti-myeloperoxidase antibodies and three of these were also negative for anti-elastase antibodies, suggesting further unidentified target antigen or antigens associated with the pANCA. Fifteen of the 34 sera positive for ANCA also demonstrated anti-nuclear staining on Hep-2 cells (53%) in a speckled, homogeneous, or nucleolar pattern. ANA were significantly associated with the presence of pANCA (P less than 0.01), and levels of ANA and ANCA fell in parallel after treatment. One serum with a pANCA was also positive for anti-GBM antibodies. Inhibition studies using ELISAs for anti-GBM antibodies indicated that there was no cross-reactivity between target molecules recognized by these antibodies. The diversity of target molecules recognized by ANCA suggests that cross-reactivity with bacterial structures is less likely as the primary aetiological event in the development of these antibodies than tissue destruction; and that cross-reactivity with vascular endothelium is also unlikely as the pathogenetic basis of vessel disease.

Immunochemically detected nuclear envelope-associated cytochrome P-450 component(s) in rat hepatocyte culture lines.

The presence and location of cytochrome P-450 in Donryu rat hepatocyte culture lines, Ac2F cells and 3 other cell lines were assessed by indirect immunofluorescence examination using anti-cytochrome P-450 monoclonal antibodies. Ac2F cells and other hepatocyte cell lines were selectively stained at their nuclear envelope, but not the cytoplasm, with a monoclonal antibody selective to a high-spin form of cytochrome P-448 (P-448H), although this monoclonal antibody stained primary cultured normal rat hepatocytes at both cellular components and did not stain hepatoma cells of 2 transplantation lines. The results of unscheduled DNA synthesis assay with Ac2F cells using several carcinogenic aromatic amines (4-aminoazobenzene derivatives and amino acid pyrolysis products) suggested that this nuclear envelope-associated cytochrome P-450 activates a restricted portion of these aromatic amines, i.e., a tryptophan pyrolysis component and a glutamic acid pyrolysis component. These results indicate that rat hepatocyte culture lines lack (or contain a reduced amount of) the cytoplasmic cytochrome P-450 but maintain a characteristic type of cytochrome P-450, probably a kind of cytochrome P-448H in their nuclear envelope, and this may be involved in oxidative metabolism of a restricted portion of aromatic amines.