Neuroanatomical distribution of the enkephalinergic and tachykininergic systems in the alpaca brainstem: an immunohistochemical study.

INTRODUCTION: A recent study has shown a close neuroanatomical relationship between the enkephalinergic (methionine-enkephalin) and tachykininergic (substance P) systems in the alpaca diencephalon. In this study, our aim is to show this relationship in the alpaca brainstem. MATERIAL AND METHODS: Using an immunohistochemical technique, the distribution of immunoreactive (Ir) fibers and cell bodies containing substance P (SP) or methionine-enkephalin (MET) has been studied in the alpaca brainstem. Five adult males were used; brain tissue was fixed and processed by standard methods. RESULTS: SP- and MET-Ir fibers showed a widespread and similar distribution in the mesencephalon, pons and medulla oblongata. The co-localization of fibers containing SP or MET was found in most of the nuclei/tracts of the alpaca brainstem. This close neuroanatomical relationship suggests multiple physiological interactions between both neuropeptides. The distribution of the cell bodies containing SP was very restricted (cell bodies were only observed in a few nuclei located in the mesencephalon and medulla oblongata), whereas MET-Ir perikarya showed a moderately widespread distribution in the mesencephalon, pons and medulla oblongata. CONCLUSIONS: This study increases the knowledge on the neuroanatomical distribution/relationship of the tachykininergic (SP) and enkephalinergic (MET) systems in the alpaca central nervous system.

A close neuroanatomical relationship between the enkephalinergic (methionine-enkephalin) and tachykininergic (substance P) systems in the alpaca diencephalon.

INTRODUCTION: In the alpaca diencephalon, the distribution of immunoreactive cell bodies and fibers containing methionine-enkephalin (MET) or substance P (SP) has been studied. MATERIAL AND METHODS: The immunohistochemical study was performed by standard method on the diencephalon of four male alpacas that lived at sea level. RESULTS: Nerve fibers containing MET or SP were widely distributed in the thalamus and hypothalamus. METand SP-immunoreactive fibers showed a similar distribution in the whole diencephalon. Immunoreactive cell bodies containing MET or SP were only observed in the hypothalamus. The distribution of MET-immunoreactive cell bodies was more widespread than that observed for cell bodies containing SP. CONCLUSIONS: A close neuroanatomical relationship between the tachykininergic (SP) and enkephalinergic (MET) systems was observed in the whole diencephalon suggestive of the existence of multiple physiological interactions between both systems.

Overexpression of kynurenic acid and 3-hydroxyanthranilic acid after rat traumatic brain injury.

Using an immunohistochemical technique, we have studied the distribution of kynuneric acid (KYNA) and 3-hydroxyanthranilic acid (3-HAA) in a rat brain injury model (trauma). The study was carried out inducing a cerebral ablation of the frontal motor cortex. Two mouse monoclonal specific antibodies previously developed by our group directed against KYNA and 3-HAA were used. In control animals (sham-operated), the expression of both KYNA and 3-HAA was not observed. In animals in which the ablation was performed, the highest number of immunoreactive cells containing KYNA or 3-HAA was observed in the region surrounding the lesion and the number of these cells decreased moving away from the lesion. KYNA and 3-HAA were also observed in the white matter (ipsilateral side) located close to the injured region and in some cells placed in the white matter of the contralateral side. The distribution of KYNA and 3-HAA perfectly matched with the peripheral injured regions. The results found were identical independently of the perfusion date of animals (17, 30 or 54 days after brain injury). For the first time, the presence of KYNA and 3-HAA has been described in a rat trauma model. Moreover, by using a double immunocytochemistry protocol, it has been demonstrated that both metabolites were located in astrocytes. The findings observed suggest that, in cerebral trauma, KYNA and 3-HAA are involved in tissue damage and that these compounds could act, respectively, as a neuroprotector and a neurotoxic. This means that, in trauma, a counterbalance occurs and that a regulation of the indoleamine 2,3 dioxygenase (IDO) pathway could be required after a brain injury in order to decrease the deleterious effects of ending metabolites (the neurotoxic picolinic acid). Moreover, the localization of KYNA and 3-HAA in the contralateral side of the lesion suggests that the IDO pathway is also involved in the sprouting and pathfinding that follows a traumatic brain injury.

GEMALS: A promising therapy for amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that currently has no cure. At present, the only approved treatment for ALS is Riluzole, a glutamate release blocker that improves life expectancy by 3-6 months. ALS-Endotherapia (GEMALS) is a novel therapeutic approach to treat ALS and the aim of the present study was to investigate the potential beneficial effects of this novel treatment. A total of 31 patients with ALS were assessed in the current study. Deceleration of the disease was observed in 83.87% (P<0.0001) of patients and mean life expectancy was increased by 38 months. Motor functions, including breathing, walking, salivation, speech, swallowing and writing, were also improved in patients treated with GEMALS. The results of the present study demonstrate that long-term treatment with GEMALS has a curative effect in patients with ALS. Furthermore, the overall effectiveness of GEMALS was assessed using the ALS Assessment Questionnaire. The score improvement was 76.2 and 100% for men and women, respectively (P<0.0001), compared with the worldwide reference score. The present study provides a promising basis for the use of GEMALS as a therapeutic treatment for patients with ALS; however, these results must be confirmed in a double-blinded and randomized clinical trial.

Immunohistochemical mapping of neurotensin in the alpaca diencephalon.

INTRODUCTION: The distribution of the immunoreactive cell bodies and fibers containing neurotensin in the alpaca diencephalon was determined by an immunohistochemical technique. MATERIAL AND METHODS: The study was carried out in four male alpacas that lived at sea level. Brains of deeply anesthetized animals were fixed by perfusion with 4% paraformaldehyde. Cryostat sections were stained by a standard immunohistochemical method. RESULTS: Cell bodies containing neurotensin were observed in the zona incerta and hypothalamus. A low/moderate density of these cell bodies was observed in the lateral hypothalamic area, anterior and dorsal hypothalamic areas, suprachiasmatic nucleus, periventricular region of the hypothalamus and in the ventromedial hypothalamic nucleus. In both thalamus and hypothalamus, immunoreactive fibers showed a widespread distribution. In the thalamus, a high density of these fibers was mainly found in the midline nuclei, whereas in the hypothalamus a high density was in general observed in the whole structure. CONCLUSIONS: In comparison with other mammals, the thalamus of the alpaca showed the most widespread distribution of neurotensin-immunoreactive fibers. The widespread distribution of neurotensin through the alpaca diencephalon suggests that the peptide can be involved in many physiological actions.

Gemst: a taylor-made combination that reverts neuroanatomical changes in stroke.

In a single transient middle cerebral artery occlusion model of stroke and using immunohistochemical techniques, the effects of a new therapeutic approach named Gemst (a member of the Poly-L-Lysine innovative therapies) have been studied in the rat brain. The expression of inflammatory (CD45, CD11b), oxidative (NO-tryptophan, NO2-tyrosine) and indoleamine 2, 3-dioxygenase pathway (kynurenic acid, 3-hydroxy anthranilic acid) markers has been evaluated in early and late phases of stroke. For this purpose, we have developed eight highly specific monoclonal antibodies directed against some of these markers. In the early phase (3 and 5 days of the stroke, we observed no effect of Gemst treatment (7.5 mg/day, subcutaneously for 3, 5 days). In the late phase (21 days) of stroke and exclusively in the ipsilateral side of non-treated animals an overexpression of kynurenic acid, 3-hydroxy anthranilic acid, CD45, CD11b, GFAP and ionized calcium-binding adapter molecule 1 (IBA-1) was found. In treated animals, the overexpression of the four former markers was completely abolished whereas the overexpression of the two latter ones was decreased down to normal levels. Gemst reversed the pathological conditions of stroke to normal situations. Gemst exerts a multifunctional action: down-regulates the indoleamine 2, 3-dioxygenase pathway and abolishes brain infiltration, microglial activation and gliosis. Moreover, Gemst has no effect on the expression of doublecortin, a protein involved in neuronal migration. Gemst could be a new drug for the treatment of stroke since it reverses the pathological findings of stroke and normalizes brain tissue conditions following the ischemic insult.

Follow-up of multiple sclerosis patients treated with Endotherapia (GEMSP).

Endotherapia (GEMSP) is a novel therapeutic approach for multiple sclerosis (MS). The aim of the present study was to demonstrate the efficiency of Endotherapia in the follow-up of 193 patients with MS. The efficiency coefficient that was evaluated was the Expanded Disability Status Scale (EDSS) score, which is a functional scale of MS progression. The evaluated score of each patient during follow-up visits was compared with the theoretical score of the disease progression without GEMSP. The evolution of the EDSS score was evaluated according to the inclusion score. The quantitative global study of the EDSS score highlighted a statistically significant difference between the final average scores of the treatment with GEMSP (M) and worldwide reference (R) groups. The improvement of the M group compared with the R group was 24.5%. According to the final EDSS scores, the study highlighted a difference in favor of the M group with 62.0% for scores ≤3, 7.8% for scores between 3 and 6 and 19.6% for scores ≥6. According to the qualitative evolution of the EDSS scores, the improvements in favor of group M were 49.3% for scores ≤3, 79.1% for scores between 3 and 6 and 19.5% for scores ≥6. The qualitative study of the EDSS score showed a statistically significant success percentage; the success percentages were between 59.1 and 90.0%. In a larger population of MS patients, the data confirm the beneficial effects of GEMSP that were previously reported in pre-clinical and clinical studies. In addition, 78% of patients showed an improvement or deceleration of the disease.

Generation of specific antisera directed against D-amino acids: focus on the neuroanatomical distribution of D-glutamate and other D-amino acids.

This review updates the findings about the anatomical distribution (using immunohistochemical techniques) and possible functions of D-glutamate in the central nervous system of mammals, as well as compares the distribution of D-glutamate with the distribution of the most studied D-amino acids: D-serine and D-aspartate. The protocol used to obtain highly specific antisera directed against D-amino acids is also reported. Immunoreactivity for D-glutamate was found in dendrites and cell bodies, but not in nerve fibers. Perikarya containing D-glutamate were found in the mesencephalon and thalamus. The highest density of cell bodies was found in the dorsal raphe nucleus, the mesencephalic central grey matter, the superior colliculus, and in the subparafascicular thalamic nucleus. In comparison with the distribution of immunoreactive cell bodies containing D-serine or D-aspartate, the distribution of D-glutamate-immunoreactive perikarya is less widespread. Currently, the physiological actions mediated by D-glutamate in the brain are unknown but the restricted neuroanatomical distribution of this D-amino acid suggests that D-glutamate could be involved in very specific physiological mechanisms. In this sense, the possible functional roles of D-glutamate are discussed.

Detection of pantothenic acid-immunoreactive neurons in the rat lateral septal nucleus by a newly developed antibody.

INTRODUCTION: The available immunohistochemical techniques have documented restricted distribution of vitamins in the mammalian brain. The aim of the study was to develop a highly specific antiserum directed against pantothenic acid to explore the presence of this vitamin in the mammalian brain. MATERIAL AND METHODS: According to ELISA tests, the anti-pantothenic acid antiserum used showed a good affinity (10-8 M) and specificity. The antiserum was raised in rabbits. Using an indirect immunoperoxidase technique, the mapping of pantothenic acid-immunoreactive structures was carried out in the rat brain. RESULTS: Pantothenic acid-immunoreactive perikarya were exclusively found in the intermediate part of the lateral septal nucleus. These cells were generally small, round, fusiform or pyramidal and showed 2-3 long (50-100 µm) immunoreactive dendrites. Any immunoreactive axons containing pantothenic acid were detected. CONCLUSIONS: The very restricted anatomical distribution of the pantothenic acid suggests that this vitamin could be involved in some specific neurophysiological mechanisms.

Lauryl-poly-L-lysine: A New Antimicrobial Agent?

The development of multiple antibiotic resistance is a global problem. It is necessary to find new tools whose mechanisms of action differ from those of currently used antibiotics. It is known that fatty acids and cationic polypeptides are able to fight bacteria. Here, we describe the synthesis of fatty acids linked to a polypeptide with antibacterial activity. The linkage of fatty acids to a polypeptide is reported to increase the antibacterial effect of the linked fatty acid in comparison with free fatty acids (FA) or free poly-L-lysine (PLL) or a mixture of both (FA free + PLL free). A number of C6-C18 fatty acids were linked to PLL to obtain new synthetic products. These compounds were assessed in vitro to evaluate their antibacterial activity. Some fatty acid-PLLs showed a good ability to fight bacteria. Their bactericidal activity was evaluated, and, lauryl linked to PLL was found to be the most active product against both Gram-positive and Gram-negative bacteria. This new active component showed a good degree of specificity and reproducibility and its minimum inhibitory concentration (MIC) was comparatively good. The antibacterial activity of the lauryl-PLL compound suggests that it is a new and promising antimicrobial agent.

GEMSP exerts a myelin-protecting role in the rat optic nerve.

OBJECTIVES: Chronic experimental autoimmune encephalomyelitis (EAE) was induced in rats to evaluate the potential protective effect of GEMSP, a mixture made up of fatty acids (FA), vitamins, and amino acids or their derivatives, linked to Poly-L-Lysine, on the myelin sheath of the optic nerve. METHODS: To evaluate the effects of GEMSP on the optic nerve, animals were divided into three experimental groups: (1) EAE rats treated with GEMSP; (2) EAE rats treated with 0.9% NaCl; and (3) control, non-EAE rats. Using electron microscopy, we investigated the possibility that this new drug candidate has a myelin-protective role. RESULTS: A marginally significant reduction in the thickness of the myelin around optic nerve medium-size axons (diameter between 0.8-1.3 µm) was found in EAE rats. Treatment of EAE rats with GEMSP ameliorated myelin damage. Significantly increased myelin thickness was found when animals in groups 2 and 3 were compared. However, the number of myelinated axons studied was not altered in groups 1 or 2 when compared to controls. DISCUSSION: Our results suggest that in a model of demyelination, GEMSP protects and enhances the formation of the myelin sheath of the optic nerve and therefore could be a potential drug candidate to reduce optic nerve pathogenesis in multiple sclerosis (MS).

Mapping of alpha-neo-endorphin- and neurokinin B-immunoreactivity in the human brainstem.

We have studied the distribution of alpha-neo-endorphin- or neurokinin B-immunoreactive fibres and cell bodies in the adult human brainstem with no prior history of neurological or psychiatric disease. A low density of alpha-neo-endorphin-immunoreactive cell bodies was only observed in the medullary central gray matter and in the spinal trigeminal nucleus (gelatinosa part). Alpha-neo-endorphin-immunoreactive fibres were moderately distributed throughout the human brainstem. A high density of alpha-neo-endorphin-immunoreactive fibres was found only in the solitary nucleus (caudal part), in the spinal trigeminal nucleus (caudal part), and in the gelatinosa part of the latter nucleus. Neurokinin B-immunoreactive cell bodies (low density) were found in the periventricular central gray matter, the reticular formation of the pons and in the superior colliculus. The distribution of the neurokinin-immunoreactive fibres was restricted. In general, for both neuropeptides the density of the immunoreactive fibres was low. In the human brainstem, the proenkephalin system was more widely distributed than the prodynorphin system, and the preprotachykinin A system (neurokinin A) was more widely distributed than the preprotachykinin B system (neurokinin B).

GEMSP: a new therapeutic approach to multiple sclerosis.

A new therapeutic approach called Endotherapia (GEMSP) for the treatment of Multiple Sclerosis (MS) is suggested. Endotherapia is the result of an immunopathological strategy addressing chronic incurable diseases with a multifactorial etiology. This approach combines a biomedical evaluation of circulating immunoglobulins directed against specific self-antigens and self-antigens modified by free radicals. GEMSP is a "tailor-made" combination of small molecules (fatty acids, antioxidants, radical scavengers, amino acids) linked to a non-immunogenic linear chain of poly-L.lysine (PLL). Each individual linkage or PLL derivative offers great advantages, such as an increase in the half-life of the active small molecules. GEMSP inhibits brain leukocyte infiltration and abolishes episodes of experimental autoimmune encephalomyelitis. In a clinical trial with 102 MS patients treated with GEMSP Endotherapia, 28% of them showed a worsening of their state; 20% showed a decrease in the progression of the disease; 17% showed disease stabilization; and 35% showed a reversal of the evolution of disease; i.e., an improvement in their disease state. In 72% of the cases, a positive evolution of the state of the MS patients treated with Endotherapia was observed (a decrease or stabilization of disease evolution or an improvement). Endotherapia is very safe and no side-effects were reported for GEMSP. Moreover, GEMSP showed no toxicity either in experimental animals or in humans. It seems that Endotherapia is a promising therapy for MS, with no side-effects, which should be considered in the management of long-term pathologies.

Frontiers in vitamin research: new antibodies, new data.

Since 2004, the anatomical distribution of vitamins in the monkey brain, studied using immunohistochemical techniques and new tools (specific antisera that discriminate different vitamins reasonably well), has been an ongoing research field. The visualization of immunoreactive structures containing vitamins (folic acid, riboflavin, thiamine, pyridoxal, and vitamin C) has recently been reported in the monkey brain (Macaca fascicularis), all these vitamins showing a restricted or very restricted distribution. Folic acid, thiamine, and riboflavin have only been observed in immunoreactive fibers, vitamin C has only been found in cell bodies (located in the primary somatosensory cortex), and pyridoxal has been found in both fibers and cell bodies. Perikarya containing pyridoxal have been observed in the paraventricular hypothalamic nucleus, the periventricular hypothalamic region, and in the supraoptic nucleus. The fibers containing vitamins are thick, smooth (without varicosities), and are of medium length or long, whereas immunoreactive cell bodies containing vitamins are round or triangular. At present, there are insufficient data to elucidate the roles played by vitamins in the brain, but the anatomical distribution of these compounds in the monkey brain provides a general idea (although imprecise and requiring much more study) about the possible functional implications of these molecules. In this sense, here the possible functional roles played by vitamins are discussed.

Changes in the morphology and lability of lysosomal subpopulations in caerulein-induced acute pancreatitis.

BACKGROUND AND AIMS: Lysosomes play an important role in acute pancreatitis (AP). Here we developed a method for the isolation of lysosome subpopulations from rat pancreas and assessed the stability of lysosomal membranes. METHODS: AP was induced by four subcutaneous injections of 20 µg caerulein/kg body weight at hourly intervals. The animals were killed 9h after the first injection. Marker enzymes [N-acetyl-ß-D-glucosaminidase (NAG), cathepsin B and succinate dehydrogenase (SDH)] were assayed in subcellular fractions from control pancreas and in pancreatitis. Lysosomal subpopulations were separated by Percoll density gradient centrifugation and observed by electron microscopy. NAG molecular forms were determined by DEAE-cellulose chromatography. RESULTS: AP was associated with: (i) increases in the specific activity of lysosomal enzymes in the soluble fraction, (ii) changes in the size and alterations in the morphology of the organelles from the lysosomal subpopulations, (iii) the appearance of large vacuoles in the primary and secondary lysosome subpopulations, (iv) the increase in the amount of the NAG form associated with the pancreatic lysosomal membrane as well as its release towards the soluble fraction. CONCLUSIONS: Lysosome subpopulations are separated by a combination of differential and Percoll density gradient centrifugations. Primary lysosome membrane stability decreases in AP.

Endotherapia: a new frontier in the treatment of multiple sclerosis and other chronic diseases.

Currently, several drugs are accessible for the treatment of many chronic diseases (multiple sclerosis, amyotrophic lateral sclerosis, rheumatoid arthritis, etc.), but most of them have a large list of side effects. Here, we propose a new therapeutic approach called Endotherapia for the treatment of chronic diseases. This approach combines a biomedical evaluation of circulating immunoglobulins directed against specific self-antigens and self-antigens modified by free radicals. The therapy proposed here is a "tailor-made" combination of small molecules (e.g., fatty acids and vitamins) linked to a non-immunogenic chain of poly-L.Lysine (PLL). Each individual linkage or PLL derivative offers great advantages, such as an increase in the half-life of the active small molecules. Endotherapia also involves clinical aspects, allowing an exact diagnosis of the disease and the identification of specific circulating antibodies in the serum of patients in several clinical trials (e.g., multiple sclerosis). Endotherapia has been shown to be very safe. In summary, Endotherapia is the result of an immunopathological strategy addressing chronic incurable diseases with a multifactorial etiology. In light of the results obtained, it seems that Endotherapia is a promising therapy for chronic diseases, with no side effects, which is evidently mandatory in the management of long-term pathologies.

New drug therapies for multiple sclerosis.

PURPOSE OF REVIEW: Multiple sclerosis (MS) is an autoimmune and inflammatory disease of the central nervous system (CNS) that causes neurological disability in young adults and that to date has no cure. Until now, expensive and only partially efficacious therapies have become available. For this reason, researchers, clinicians and pharmaceutical companies are currently investigating new drugs for the treatment of MS. Here, we review the most recent data on drug candidates for MS. RECENT FINDINGS: In the preclinical phase, such drug candidates have shown a beneficial effect on the onset of experimental autoimmune encephalomyelitis (microtubule-stabilizing drugs, MS14, Lithium, GEMSP...), a decrease in CNS cell infiltrates (recombinant T cell receptor ligand, lovastatin-rolipram, ribavirin, GEMSP...), prevention of demyelination (lovastatin-rolipram, calpain inhibitor, lithium...); and a reduction of axonal loss (phenytoin, lovastatin-rolipram, calpain inhibitor). In clinical trials, drug candidates against MS have shown safety (rituximab, ustekinumab, intravenous immunoglobulin, laquinimod, BHT-3009, fumarate, chaperonin 10, GEMSP...), an improvement of gadolinium-enhanced lesions (protiramer, fingolimod, laquinimod, BHT-3009, fumarate, daclizumab...), and an improvement of the relapse rate (fingolimod, fumarate...). SUMMARY: Future research into MS should focus on a combination of therapies and on the development of drugs directed against the remitting and progressive phases of the disease. In this sense, MS is a very complex multifactorial disease that requires treatment able to cover all the aspects of MS and not only the anti-inflammatory aspect.

Rolipram and SP600125 suppress the early increase in PTP1B expression during cerulein-induced pancreatitis in rats.

OBJECTIVES: To analyze the expression modulation of pancreatic protein tyrosine phosphatase (PTP)1B during the development of cerulein (Cer)-induced acute pancreatitis (AP) and the effect of inhibition of type 4 phosphodiesterase and c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2 on its expression levels. METHODS: Acute pancreatitis was induced in rats by subcutaneous injections of 20 microg Cer per kilogram body weight at hourly intervals, and the animals were killed at 2, 4, or 9 hours after the first injection. Neutropenia was induced with vinblastine sulfate. Phosphodiesterase and the mitogen-activated protein kinases were inhibited with rolipram and SP600125, respectively, before the induction of AP. RESULTS: Protein tyrosine phosphatase 1B increases its expression at the levels of both protein and messenger RNA during the early phase of Cer-induced AP. The increase in protein expression persisted along the development of the disease, and neutrophil infiltration seemed to play a central role. Rolipram and SP600125 pretreatments mostly suppressed the increase in the expression of PTP1B during the early phase of AP. CONCLUSIONS: Cerulein-induced AP is associated with an increase in the expression of PTP1B in its early phase. An increase in cyclic adenosine monophosphate levels in inflammatory cells and the inhibition of c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2 are able to suppress the increase in PTP1B protein level.

Circulating antibodies directed against "polycyclic aromatic hydrocarbon-like" structures in the sera of cancer patients.

BACKGROUND: An increase in immunoglobulin (Ig) A isotype directed against benzo(a)pyrene (BP) structure has previously been described in sera of cancer patients. In this study, new polycyclic aromatic hydrocarbon (PAH) conjugates were synthesized in order to more closely mimic the endogenous ligands of the cytosolic aryl hydrocarbon receptor (AhR). PAH [benzo(a)pyrene; 1,2-benzanthracene; dibenz[a,c]anthracene; 7,12-dimethylbenza[a]anthracene; benzo(ghi)perylene] were bound to protein carriers such as bovine serum albumin (BSA) via N-acetyl-cysteine (NAC). METHODS: The levels of circulating antibodies (Abs) directed against PAH-NAC conjugates in the sera of cancer patients were evaluated using an Enzyme-Linked Immunosorbent Assay (ELISA) with these new conjugates. The avidity (IC(50)) and specificity of these circulating Abs were assessed via competition experiments. RESULTS: An increase in Ig directed against these PAH-NAC conjugates was found in the sera of cancer patients, irrespective of the state and stage of the tumors. These Ig were principally of the A isotype. Sera from cancer patients had significantly higher optical density (OD) ranges than the controls, p<0.0001. The ELISA test for breast cancer (n=155) and ovarian cancer (n=62) identified 82% and 92% of positive patients, respectively. The percentage positive in the control group (n=60) was around 5%. Moreover, competition experiments with the different PAH-NAC conjugates and NAC-BSA revealed an estimated avidity of 10(-6)M for the circulating IgA antibodies. CONCLUSIONS: The Abs discriminated between the different PAH-NAC conjugates and NAC-BSA. Therefore, these Abs recognize a carcinogenic PAH-NAC structure and not only a BP structure. These markers may be useful in the future for monitoring cancer evolution and recurrence.