The interleukin-33 receptor ST2 is important for the development of peripheral airway hyperresponsiveness and inflammation in a house dust mite mouse model of asthma.

BACKGROUND: Several clinical and experimental studies have implicated IL-33 and its receptor ST2 in the development of asthma. However, the effect of IL-33/ST2 signalling on airway responses and inflammation in allergic asthma is not well established. OBJECTIVE: To investigate the role of IL-33/ST2 signalling in promoting allergen-induced airway hyperresponsiveness (AHR), airway inflammation, antigen-specific IgE production and mast cell activity in a mouse model of asthma. METHODS: ST2-deficient (ST2(-/-)) mice and control BALB/c mice were given house dust mite (HDM) extract over a 6-week period. Forty-eight hours after the final HDM administration, lung function and airway inflammation were evaluated. Airway responsiveness was determined in the central airways and peripheral lung. Cellular infiltration and mast cell protease mMCP-1 levels were quantified in bronchoalveolar lavage fluid (BALF). Recruitment of inflammatory cells and inflammatory cytokine profiles were assessed in pulmonary tissue, and HDM-specific IgE was measured in serum. RESULTS: ST2 deficiency diminished HDM-induced AHR in the peripheral lung, while AHR in the central airways was unaffected. Inflammatory responses to HDM were also reduced in ST2(-/-) mice as reflected by the lower induction of HDM-specific serum IgE, inhibition of HDM-induced eosinophilia and reduced macrophage count in BALF, and a diminished influx of inflammatory cells and reduced goblet cell hyperplasia around the peripheral airways. Furthermore, the levels of the inflammatory cytokines IL-1ß, IL-5, IL-13, IL-33, GM-CSF, thymic stromal lymphopoietin and mast cell protease mMCP-1 were reduced in HDM-treated ST2(-/-) mice compared with wild-type controls. CONCLUSIONS: In addition to promoting Th2 inflammation, we now suggest a role for the IL-33/ST2 pathway for the induction of peripheral inflammation and mucus production that causes AHR in the peripheral lung. This mechanism for inducing AHR at distal parts of the lung may be of specific importance as asthma is considered as a small airway disease.

Characterization of the dog lipocalin allergen Can f 6: the role in cross-reactivity with cat and horse.

BACKGROUND: Allergy to the domestic dog (Canis familiaris) affects 5-10% of the population in affluent countries. Three of four patients are allergic to more than one pet, which can only partially be explained by cross-reactivity between serum albumins. The lipocalin protein family harbours allergens in mammalian species. METHODS: We set out to clone and characterize a novel dog allergen, and investigate its potential role in cross-sensitization between dog, cat and horse. The gene encoding Can f 6 was amplified from dog skin and bladder cDNA libraries. The corresponding allergen was produced and purified by recombinant techniques and evaluated by SDS-PAGE, size exclusion chromatography, circular dichroism spectra, ELISA and basophil activation test. RESULTS: IgE antibodies to Can f 6 were found in serum from 38% of dog-sensitized subjects. Sequence similarities between the lipocalin allergens Can f 6, Fel d 4 (cat) and Equ c 1 (horse) suggested a probability for cross-reactivity, which was demonstrated by competitive ELISA. The biological relevance of Can f 6 was confirmed by basophil activation test in dog-allergic patients. CONCLUSION: Can f 6 is a new lipocalin dog allergen that cross-reacts with lipocalins from horse and cat. Can f 6 and homologous allergens may contribute to multisensitization and symptoms in individuals allergic to mammals.

Neural cell adhesion molecule in breast, colon and lung carcinomas.

Neural cell adhesion molecules (NCAM) play an important role in embryogenesis and in some tumors, especially of neuroectodermal origin. In this study, 18 cases of invasive breast carcinoma, 7 cases of sigmoid colon carcinomas and 17 cases of the non-small-cell lung carcinoma were immunostained for NCAM. NCAM expression, usually focal, was observed in some cases only. NCAM was expressed in the membranes, in a fine granular pattern. In 3 cases of breast cancer cytoplasmic localisation of NCAM was also observed, which may suggest its cytoplasmic formation. Furthermore, in 3 cases expression of NCAM in histologically normal ductal lobular units adjacent to invasive breast cancers without the presence of this antigen in cancer tissue was observed. The immunostaining was weak or absent in sigmoid colon carcinomas. In this study we confirm the observation of some authors that NCAM expression occurs in some cases of non-small-cell lung carcinomas.

Malformations of angiogenesis in the low differentiated human carcinomas. immunohistochemical study.

Our previous observations showed that the perivascular mesenchyma of the thin-walled vessels (capillaries) in cancers may be the source of organ-specific stem cells. We suggested that the cells forming vascular channels in altered stroma participate in the tumor development. This study was designed to examine the distribution of the vessels and their appearance in the breast, lung and colon cancers. Using immunohistochemical methods, we have shown that in the low differentiated tumors both CD31 and factor VIII antigens may be expressed in capillaries chiefly on the periphery of neoplastic foci. Many of these vessels were discontinuous, with interruptions or unformed tubules. Sporadically, CD31 protein and factor VIII antigens were not expressed in capillaries inside the very low differentiated cancer cases. It is difficult to assess by immunohistochemical means whether the vascular malformations are the primary or secondary phenomena in the malignancy and why these abnormalities were especially visible in some low differentiated cancers.

Nitric oxide synthase type 1 expression in human lung cancer and its relation to p53.

BACKGROUND: The nitric oxide synthases (NOS) have been observed in human tumour cell lines as well as in solid tumours. Neuronal isoform of NOS (NOS1) was particularly abundant in low-differentiated gynaecological, breast and central nerve system tumours, suggesting that it may characterize poorly differentiated tumours. So far, little is known about expression of the neuronal NOS isoform in non-small cell lung cancer. Our aim was to compare NOS1 expression in non-small lung carcinomas with respect to tumor staging and p53 protein expression. MATERIAL AND METHODS: Thirty-two cases of non-small lung carcinomas of all grades of malignancy and ten control lung specimens with neoplastic lesions were examined. Paraffin-embedded tissues were stained with hematoxylin and eosin, or with antibodies to NOS1 and p53, and evaluated under light microscope. RESULTS: No statistical correlation between expression of p53, NOS1 and degree od tumour differentiation was observed. CONCLUSION: Expression of NOS1 can not serve as a marker for highly malignant tumours in the non-small cell lung carcinomas.

Correlation between liver damage and degree of gastric mucose colonization by Helicobacter pylori in subjects with parenchymatous liver damage.

BACKGROUND: Helicobacter pylori (H. pylori) is an important factor responsible for chronic inflammatory conditions of the gastric mucosa. It has been demonstrated in numerous animal studies that some Helicobacter species may cause parenchymatous liver damage. The aim of the study was to investigate whether there is any correlation between the incidence of parenchymatous liver damage, and the incidence and degree of colonization of the gastric mucosa by H. pylori. MATERIAL AND METHODS: The study was carried out in the group of 30 patients (14 females, 16 males) whose mean age was 37 years, hospitalized because of parenchymatous liver damage without clinical symptoms of cirrhosis. All the patients had gastroscopy and urease tests performed, and mucosal biopsies were taken for immunomorphological investigations. The patients were divided into groups, group I comprising those with positive, and group II with negative urease test results. RESULTS: Positive urease tests were obtained in 26/30 patients (group I), 18/26 of whom demonstrated macroscopic changes of the gastric mucosa visible in gastroscopy. Group II with negative urease test results comprised 4/30 patients, 2/4 of whom had detectable changes in the gastric mucosa. The presence of H. pylori antigens was demonstrated by gastric mucosa immunomorphology in all 30 patients. The degree of invasion of H. pylori was visualized by immunofluorescence, which allowed to differentiate deep mucosal invasion of H. pylori (bacterial antigens present in lymph follicles and at the base of muciferous glands) observed in group I in 14/26 and in group II in 1/4 cases and superficial invasion (epithelium and mucosal surface) observed in group I in 12/26, in group II in 3/4. CONCLUSIONS: The obtained results may suggest more frequent H. pylori infections in subjects with parenchymatous liver damage than in the population without liver damage. Immunofluorescence seems to be a highly sensitive method allowing for detection of even small degrees of gastric mucosa colonization by H. pylori.

[Necrotizing sialometaplasia. Case report]. / Martwicza metaplazja slinianki podzuchwowej. Opis przypadku.

The authors present a rare case of inflammatory disease of submandibular salivary gland (necrotizing sialometaplasia), in which the histopathological examination was of particular value while estimating the final diagnosis. Review of world literature concerning this disease was made.

Substance-P of neural cells in human trigeminal ganglion.

Expression of substance-P in human neurons of trigeminal ganglia has been investigated by immunohistochemistry and morphometry. These neurons constituted 12.8% to 32.6% of the total neuronal population in the trigeminal ganglia. Substance-P positive granulations were concentrated around the nucleus, distributed focally in neuroplasm or dispersed over the neuroplasm. Morphometric analysis has indicated the presence of three populations of SP-positive cells: small, medium-sized and large. The results suggest a functional differentiation on the level of the first neurons of the afferent path of the stomatognathic system. Substance-P is likely to play a role in the transmission not only of nociceptive impulses but also of those involved in the mechano-functional stimulation of system activities.

Dendritic and cancer cells in the breast tumors--an immunohistochemical study: short communication.

Normal and dysplastic mammary glands express immunocompetent S-100 protein positive dendritic cells (DCs), which are located in a regular pattern, in the suprabasal cell layer of the ducts and alveolar nodules. The epithelial cells, however, are S-100 protein negative. Since some breast cancers also express the S-100 protein, our aim was to check the diagnostic and prognostic value of the S-100 protein distribution combined with the tumor grade and expression of synaptophysin (Syn), chromogranin A (Chg A), c-erbB-2 oncoprotein and p53 protein in infiltrating and metastatic breast tumors. Applying immunohistochemical methods, we show in paraffin- or frozen breast tissue sections that in some cases of the infiltrating breast carcinomas, S-100 protein positive cells do not appear, whereas in other cases, either S-100 protein positive DCs are closely associated with cancer cells, or the cancer cells themselves stain positive to S-100 protein. However, we found no correlation between the S-100 protein expression and other investigated parameters.

Vasculopathy and amyloid beta reactivity in brains of patients with acquired immune deficiency (AIDS).

The authors examined multiple brain sections from 15 autopsy cases of AIDS for the vascular changes, presence of amyloid plaques and signs of axonal damage. The mean patients age was 33.8 years (range 24-48 years). Neuropathological findings included: HIV-specific changes (5), opportunistic infections (7), lymphoma (1) and two cases with nonspecific changes. All sections were stained with hematoxylin-eosin (H-E), selected sections were stained with Masson trichrome, Gomori reticulin, Congo red and thioflavine S method. Two sections from each case were immunostained for the presence of beta-amyloid (4G8). ubiquitin, alpha-smooth muscle actin and CD31. The different forms of vascular changes were found in all cases. The common changes were: lymphocytic perivascular or transmural infiltrations and hyalinization, thickening or fibrosis of the arterial and arteriolar wall. The perivascular space widening up to status lacunaris was a frequent phenomenon in the basal ganglia and deep white matter. Some of the cortical arterioles formed little multiluminal structures. Immunohistochemical examination revealed features of hypertrophy of the vascular muscular layer and signs of the slight endothelial cells proliferation. In three cases 4G8 immunopositive. Congo red and thioflavine S-negative, diffuse beta-amyloid deposits were present in the gray matter, focally their localization was perivascular. Ubiquitin immunoreactivity presented as numerous dot-like structures or focal bundles of positive widened axons in the white matter, spheroids and scattered positive neurons were also found. The authors suggest that some of morphological changes within the brain and consecutive neuropsychological symptoms in AIDS are of the vascular origin. Presence of amyloid plaques and axonal damage are the elements of the complex degenerative and inflammatory process in the brain caused by chronic inflammatory stimulation in HIV infection.

Myoid cells and neuroendocrine markers in myasthenic thymuses.

We have studied myoid cells in normal and myasthenic thymuses as well as in thymomas. For the presence of neuroendocrine markers-producing cells and identification of synaptophysin (Syn) the immunohistochemical method and immunoblot analysis were used. Myoid cells can be demonstrated in the thymus of myasthenic patients in high number. These cells occur in the vicinity of Hassall's bodies but also within them. Some regenerated Hassall's bodies displayed majority of myoid cells with their concentric arrangement around the centrally situated lacunar-like cell with nuclei of monocytogenic origin. Such phenomenon may suggest cooperation of myoid cells and their epithelial transitional forms with monocytogenic cells in various thymic hormone production. It is likely that myoid cells are the source of some thymic epithelial cells. According to some authors, thymomatous epithelial cells and skeletal muscle share a common epitope defined by a monoclonal antibody (mAb), whereas thymic epithelial cells possess acetylocholine receptor (AChR) on their surface. The epithelial cells of some thymomas express also desmin. In normal thymuses of children, Syn and chromogranin A (Chg A) were demonstrated in some cells of Hassall's bodies by immunohistochemical method. In addition, antibodies to Syn stained nerve structures surrounding the thymic blood vessels. In myasthenic thymuses, Syn expression was in cortical and medullary epithelial cells, in myoid cells and only scanty and focal in keratinized epithelial cells of Hassall's bodies. The epithelial cells of some thymomas also express Syn. In some thymuses of all groups investigated in this study Chg A was seen in single cells of Hassall's bodies and focally in cortical epithelial cells. Our results show that in normal thymuses of cardiac surgery patients and in the adult myasthenic thymuses antibody raised against Syn recognized protein with molecular weight of 48,000 but not normal (38,000) Syn. It remains to be elucidated if the overexpression of synaptophysin-like protein in myasthenic thymuses is a compensatory phenomenon to the defect in normal synaptic function.

Epithelial-mesenchymal cell interactions and participation of the neuroendocrine markers in tumor development. Immunohistochemical study.

Existence of the organ stem cell population seems to decide on ability of the tissue to regenerate and, likewise, on carcinogenesis. The source of the organ specific stem cells may be perivascular mesenchyma of thin-walled vascular channels. Our previous study on the breast cancer indicates that the perivascular mesenchyma of thin-walled vessels appears to be source of myoid cells (myofibroblasts) from which cancer cells arise. Similar results have been observed in the cancers of lung, salivary gland and colon, investigated in the current study. The perivascular cells of thin-walled channels are the source of myoid cells with expression of synaptophysin (Syn) and/or chromogranin A (Chg A), and from these cells neoplastic cells could originate. Syn and/or Chg A positive neoplastic cells were particularly well visible in connection with the vascular channels on the peripheries of tumors while other parts of tumors were only weak positive or negative for those neuroendocrine markers. Similarly as in breast cancers, the S100-protein positive dendritic cells with various of distribution were seen, expressing intimate connection with neoplastic cells. The epithelial pearls especially abundant in non-small cell lung carcinomas demonstrated immunohistochemical analogy to Hassall's bodies: they had monocytogenic cell inside and they displayed thymosin alpha 1 (TA1), as well as mucin secretion and minute calcification. Some epithelial cells expressed desmin and Syn. All types of investigated cancers demonstrated TA1. Results of our present study suggest that the perivascular cells have a differentiation defect. Such defect may initiate abnormal stromal environment, commonly observed in neogenesis, however, the presence of thymic growth factors may favor tumor growth.

Pathogenesis of breast carcinoma. Immunohistochemical study.

Synaptophysin and/or chromogranin A may be expressed in epithelial cells of normal and dysplastic mammary gland and in some cancer of the breast. This work indicates that some stromal cells form thin walled vascular channels and from their perivascular mesenchyma arise myoid-like cells, some with cross-like striations. These myoid-like cells have been stained with antibody to smooth muscle actin, rarely to desmin and sarcomeric actin as well as are strongly positive for synaptophysin and/or chromogranin A. From those cells arise cancer cells. Some cancer cells also expressed desmin, sarcomeric actin or smooth muscle actin. Because synaptophysin positive are neuromuscular endplates, it is a question whether the presence of synaptophysin in the progenitor of neoplastic cells of myogenic origin is due to the synaptic dysfunction in molecular mechanism of the epithelial-parenchyma and mesenchymal stroma interaction. The location of S100-protein positive dendritic cells distributed in regular pattern in suprabasal layer of the mammary gland indicate that these cells may arise from preadipocytes which take part in morphogenesis of the breast. All cases of the breast cancer demonstrated thymosin alpha 1, some of them also showed Hassall's-like bodies, mucin secretion and minute calcification. Whether the interaction of epithelial cells and S100-protein positive dendritic cells in tissue other than the thymus has similar dynamic activity to that of Hassall's bodies of the thymus remains to be determined. Both, epithelial cells of Hassall's bodies and epithelial cells of the investigated breast are of myogenic origin. The above consideration suggests that the cells forming vascular channels are with a differentiation defect as they are created in altered stromal mesenchyma and the presence of thymic growth factors might induce tumor growth.

Clinical and immunohistochemical analyses of parotid gland tumors.

Clinical, histological and immunohistochemical data on 71 parotid gland tumors were analyzed. Benign neoplasms accounted for 71.8% of the case material and malignant tumors 22.6%. Chronic parotitis occurred in 5.6% of the total case number. Pleomorphic adenomas and mucoepidermoid carcinomas were the most frequently occurring benign and malignant neoplasms. Pleomorphic adenomas stained positive for S-100 protein, tenascin, smooth muscle actin, synaptophysin and chromogranin A. This immunohistochemical, histological and clinical analysis was believed to be of potential assistance in the diagnosis, treatment and prognosis of parotid gland tumors.

Pretreatment values of serum CA 15-3 antigen related to prognostic factors in breast cancer patients.

In the present study results of serum CA 15-3 immunoassay obtained at diagnosis in 231 breast cancer women (average age: 54.6, range: 27-87 years) were correlated with prognostic factors of the disease; the cut-off level was established at 30.0 U/ ml. As a result, elevated mean values of serum CA 15-3 as well as positivity rates of the test were significantly associated with more advanced stage of breast cancer, presence of distant metastases, involvement of four and more axillary lymph nodes, high BLOOM and RICHARDSON grade [3], low contents of estrogen (ER) and progesterone (PgR) receptors. Although serum CA 15-3 concentrations should be paralleled the increasing tumor size, the difference being significant only for the proportion of positive results. Our findings suggest that pretreatment levels of CA 15-3 antigen represent the breast cancer extent and reflect the cell differentiation and aggressiveness of the tumor. We conclude that pretreatment concentrations of CA 15-3 antigen may be useful as a prognostic factor in breast cancer patients.

Immunohistochemical study in breast carcinoma. S100-protein positive cells and neuroendocrine differentiation.

In this study S100-protein positive cells were found in all 12 cases of benign dysplastic changes and in all of the investigated 53 cases of breast carcinomas. These cells belong to interdigitating cells (IDC) and were located in a regular pattern in the basal cell layer of the ducts and alveolar nodules in benign lesions. However, in breast carcinomas S100-protein positive IDC were in various pattern of distribution; only in the stroma, in basal cell layer, between cancer cells and S100-protein positivity of IDC and epithelial cancer cells. This phenomenon suggests the antigenic modulation of cancer cells transferring them the property of S100-protein positive cells or it may be the consequence of fusion. Immunoreactivity for chromogranin A (ChgA) and synaptophysin (Syn) was found in epithelial cells in some cases of benign dysplastic changes. However, in some carcinoma cases ChgA and Syn were revealed in carcinoma cells, in myoepithelial cells, in some stromal mesenchymal cells and endothelial cells. Immunoreactivity to smooth muscle actin was shown in the endothelial and smooth muscle cells of the vessel's wall, in myoepithelial cells and was also sporadic in carcinoma cells.

[Level of CA 15-3 antigen--a prognostic factor in patients with breast cancer?]. / Stezenie antygenu CA 15-3--czynnik rokowniczy u chorych na raka sutka?

Serum CA 15-3 concentrations were determined using sandwich enzyme immunoassay in 430 women: 214 breast cancer patients prior to any therapy, 161 patients with benign breast diseases, and 55 healthy controls; the cut-off limit was established at 30.0 U/ml. In breast cancer patients, CA 15-3 levels positively correlated with negative prognostic factors: higher tumor size (p < 0.001), positive axillary lymph nodes (p < 0.02), high histological grade (p < 0.01), low contents of estrogen (p < 0.05) and progesterone (p < 0.006) receptors. However serum CA 15-3 values raised in parallel with clinical stage of breast cancer, the difference was not significant. The overall diagnostic sensitivity and specificity of the test were 24.3% and 94.9%, respectively. The mean serum CA 15-3 values and the percentage of positive results in breast cancer patients were significantly higher as compared to benign breast diseases group (27.52 +/- 27.01 vs. 16.75 +/- 8.43, p < 0.001; 24.3% vs. 5.6%, p < 0.001, respectively) as well as to healthy controls (27.52 27.01 vs. 13.37 +/- 6.51, p < 0.001; 24.3% vs. 3.6%, p < 0.01, respectively). The sensitivity of the CA 15-3 test is low and thus not suitable for the differential diagnosis of breast lumps. Our data suggest potential prognostic value of pretreatment CA 15-3 assays in breast cancer patients.

p53 expression in breast cancer related to prognostic factors.

In this article the results of molecular marker p53 examinations were presented in relation to the following established breast cancer prognostic factors: age, histologic type, histologic grade, lymph node involvement, tumor size as well as estrogen a progesterone receptor status. Twenty one percent of these primary breast cancer specimens exhibited the overexpression of p53 protein. Significant associations were found between p53 overexpression and younger age, high histologic grade and low content of estrogen and progesterone receptors. Identification of p53-positive breast carcinomas potentially represents a clinically useful indicator of breast cancer aggressiveness.

Immunohistochemical comparative investigations of lymphatic tissue in reactive processes, myasthenic thymuses and Hodgkin's disease.

In this study coexpression of cytokeratin and desmin, and occasionally also Ki-1 antigen, was displayed in extrafollicular reticulum cells of reactive lymph nodes. The absence or expression of trace amounts of these proteins in normal lymphoid tissue suggests that activation of T cell regions is correlated with the increased frequency of cytokeratin, desmin and Ki-1 expressing cells, and therefore may be a transient phenomenon. S-100-positive interdigitating reticular cells were found occasionally in extrafollicular T cell region of normal lymph nodes. They were, however, more numerous in reactive lymphatic tissue. In the myasthenic thymuses cells forming Hassall's corpuscles displayed coexpression of cytokeratin, desmin and Ki-1 antigen. Medullary epithelial cells were also cytokeratin-positive and, additionally, Ki-1 antigen was expressed on some cells dispersed in whole thymic tissue. S-100-positive interdigitating reticular cells were especially numerous in the thymic medulla and some of them found inside the Hassall's corpuscles. In Hodgkin's disease deficiency of cytokeratin and desmin in extrafollicular reticulum cells is a constant phenomenon in spite of a classic inflammatory background. However, Ki-1 antigen displayed Reed-Sternberg cells which, similar as some thymic cell elements, appear to originate from stromal perivascular mesenchyme. This fact suggests that Reed-Sternberg cells in Hodgkin's disease are pathologic counterparts of extrafollicular reticulum cells which represent a cellular differentiation defect to produce desmin and cytokeratin but with a possibility of Ki-1 antigen expression. The consequence of this may be the disregulation of immune system and the observed immunologic abnormalities. Further studies are needed to elucidate the role of Epstein-Barr viruses in this process. S-100-positive interdigitating reticular cells were in close contact with Reed-Sternberg cells and they were especially large and with numerous cells processes in the mixed cellularity (MC) subtype. The occurrence of interdigitating reticulum cells with S-100 protein expression, especially numerous in the T cell region activated of peripheral lymphatic tissue, as well as their close contact with Reed-Sternberg cells and with cells forming Hassall's corpuscles suggest their eventual possible role in the function of the immune system.

Non-fibrillar beta-amyloid protein is associated with smooth muscle cells of vessel walls in Alzheimer disease.

Meningeal blood vessels were studied in Alzheimer disease (AD) and control brain specimens obtained from autopsies within 16 hours after death. Serial sections were stained with thioflavine S and Congo red and immunostained for the presence of beta-amyloid precursor protein (beta PP) and beta-protein and for smooth muscle-specific proteins myosin, alpha-actin, and desmin. Isolated blood vessels were studied by immunoblotting for the presence of beta PP, fragments of beta PP, and beta-protein. The arteries that were strongly immunopositive for beta-protein in all layers of the walls were also positive for amyloid fibrils on thioflavine S and Congo red stainings. The focal immunostaining for beta-protein in less affected vessels was located in the tunica media in the cytoplasm of smooth muscle cells or formed granules between myocytes. The cytoplasmic beta-protein and some of the small deposits present between cells were negative for amyloid fibrils. The vessels isolated from specimens containing beta-protein-immunoreactive material contained 3 kD, 4.2-4.5 kD, 8.5-9 kD, and 17.5 kD beta-protein-immunoreactive bands. These bands were not found in the samples assessed as beta-protein-negative by immunocytochemistry. These data indicate that during formation of amyloid in AD vessel walls, nonfibrillar, monomeric, and oligomeric beta-protein accumulate.