Loss of vessel wall viability in cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is a neuropathological feature of Alzeheimer's disease and an important cause of cerebral haemorrhage in the elderly. CAA is characterized by the deposition of Alzheimer amyloid beta protein (A beta) in cerebral and leptomeningeal vessel walls. In order to study the effect of cerebrovascular A beta deposits in vivo, living canine leptomeninges obtained from old dogs affected by CAA were analysed by confocal laser scanning microscopy after immunofluorescence staining for A beta and viability staining with fluorescein diacetate (FDA). Simultaneous detection of the two signals showed a segmental loss of leptomeningeal vessel wall viability at some site of A beta deposition. Many of the non-viable vessels segments were also dilated, suggesting that A beta-induced vascular cell death creates the loci minores resistentiae for the development of cerebral haemorrhage in CAA.     

Measurements of stability changes of titanium implants with exposed threads subjected to barrier membrane induced bone augmentation. An experimental study in the rabbit tibia

The present study was undertaken to investigate the relationship of microglial activation to amyloid beta protein (A beta) deposition, particularly at the early stage. Using single and double immunostaining methods with a panel of microglia markers and antibodies against A beta and amyloid beta protein precursor (APP), we examined the cerebrum and cerebella of both Alzheimer's disease (AD) and non-demented subjects obtained at autopsy. In nondemented, middle-aged subjects that had small amounts of cerebral A beta deposits, approximately 70% of the diffuse plaques contained ramified microglia. However, no evidence of microglial activation was found in diffuse plaques in any of the non-demented subjects. Dual immunostaining of sections of cerebral cortex using antibodies against A beta and major histocompatibility complex class II antigen showed that in AD subjects, approximately 20% of total diffuse plaques contained a few, activated microglia. Most of these plaques were defined as a transitional from between diffuse and primitive plaques. Both primitive and classic plaques in the cerebral cortex of AD subjects consistently contained clusters of activated microglia. Subpial A beta deposits without neuritic changes lacked microglial activation. In the cerebellum, all of the diffuse plaques lacked microglial activation, and activated microglia in the compact plaques were not as hypertrophic as those in cerebral primitive/classic plaques. Our findings indicate that microglial reactions are absent in the early stages of A beta deposition, and it occurs during the transition from diffuse to primitive plaques, when amounts of A beta deposits and the degree of neuritic changes increase.     

Animal models of cerebral beta-amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is a significant risk factor for hemorrhagic stroke in the elderly, and occurs as a sporadic disorder, as a frequent component of Alzheimer's disease, and in several rare, hereditary conditions. The most common type of amyloid found in the vasculature of the brain is beta-amyloid (A beta), the same peptide that occurs in senile plaques. A paucity of animal models has hindered the experimental analysis of CAA. Several transgenic mouse models of cerebral beta-amyloidosis have now been reported, but only one appears to develop significant cerebrovascular amyloid. However, well-characterized models of naturally occurring CAA, particularly aged dogs and non-human primates, have contributed unique insights into the biology of vascular amyloid in recent years. Some non-human primate species have a predilection for developing CAA; the squirrel monkey (Saimiri sciureus), for example, is particularly likely to manifest beta-amyloid deposition in the cerebral blood vessels with age, whereas the rhesus monkey (Macaca mulatta) develops more abundant parenchymal amyloid. These animals have been used to test in vivo beta-amyloid labeling strategies with monoclonal antibodies and radiolabeled A beta. Species-differences in the predominant site of A beta deposition also can be exploited to evaluate factors that direct amyloid selectively to a particular tissue compartment of the brain. For example, the cysteine protease inhibitor, cystatin C, in squirrel monkeys has an amino acid substitution that is similar to the mutant substitution found in some humans with a hereditary form of cystatin C amyloid angiopathy, possibly explaining the predisposition of squirrel monkeys to CAA. The existing animal models have shown considerable utility in deciphering the pathobiology of CAA, and in testing strategies that could be used to diagnose and treat this disorder in humans.     

Overexpression of amyloid precursor protein of Alzheimer's type in brains of intoxicated children

The coincidence of neuronal stress induced by intoxication and an overexpression of amyloid precursor protein (APP) in the brains of children was examined. Brains of ten children accidentally intoxicated by poisonous mushroom were studied by means of immunohistochemical methods using monoclonal antibodies generated against different domains of APP and glial cell markers. Overexpression of APP was found in the brain neurons of all intoxicated children. Neurons were immunopositive with the antibodies generated against the middle (amyloid beta protein) domain of APP. No extracellular deposits were found in the tissue. Our results provided, for the first time, the evidence that overexpression of APP concomitant with the neuronal stress is age-independent phenomenon appearing not only in the brain of adults but in very young individuals as well.     

Few patients with "chronic prostatitis" have significant bladder outlet obstruction

Apolipoprotein E (apoE) is one of the amyloid associated proteins that is found in the amyloid plaque of Alzheimer's disease and systemic amyloidosis. ApoE might play an important part in the etiology of Alzheimer's disease by functioning as a "pathologic chaperone" to promote the formation of amyloid filaments. In this study, we investigated whether apoE is associated with amyloid deposits of primary localized cutaneous amyloidosis using immunohistochemistry, immunogold electron microscopy, and immunoblotting. The subjects consisted of 12 patients with lichen amyloidosus and one patient with macular amyloidosis. Light microscopically, amyloid deposits in the dermal papillae were round in shape and stained with Congo red. Immunohistochemically, apoE was detected in amyloid deposits in all the cases examined. Immunogold electron microscopy showed apoE immunoreactivity on the amyloid deposition. Immunoblots of amyloid-positive skin showed 35K and 14K proteins, which were taken to be apoE and its fragment, respectively. In normal skin extract, only the 35K protein was detected by the anti-human apoE. Moreover, the intensity of the amyloid-positive skin sample was stronger than that of the normal skin sample. Monoclonal anti-cytokeratin antibody reacted with the 45K protein of the amyloid-positive skin extract. These results indicate that apoE is a component of primary localized cutaneous amyloidosis, and that it might play an important role in primary localized cutaneous amyloidosis.     

Localized amyloidosis of the seminal vesicle: identification of lactoferrin immunoreactivity in the amyloid material

Three specimens of localized amyloidosis of the seminal vesicle surgically removed for prostatic cancer were immunohistochemically analyzed to clarify the nature of the permanganate-sensitive congophilic subepithelial deposition. A variety of known amyloidogenic substances and secretory products in the seminal fluid were screened using the indirect immunoperoxidase method. In addition to reactivities with antibodies to amyloid P component and human seminal plasma, the amyloid material was immunoreactive for lactoferrin using a rabbit antiserum and two of three mouse monoclonal antibodies. All the antibodies labeled some of the normal seminal vesicle epithelial cells for this ironbinding, bacteriostatic glycoprotein. In the prostate without accompanying amyloid deposition, a considerable proportion of the glandular epithelium and secretory material were positive for lactoferrin. Pre-embedding immunoelectron microscopy showed lactoferrin immunoreactivity on the amyloid fibrils. Focal staining of the amyloid for gross cystic disease fluid protein-15 was also observed in two lesions. These findings strongly suggest that lactoferrin is the major constituent in localized senile amyloidosis of the seminal vesicle.     

Serum amyloid P component prevents proteolysis of the amyloid fibrils of Alzheimer disease and systemic amyloidosis

Extracellular deposition of amyloid fibrils is responsible for the pathology in the systemic amyloidoses and probably also in Alzheimer disease [Haass, C. & Selkoe, D. J. (1993) Cell 75, 1039-1042] and type II diabetes mellitus [Lorenzo, A., Razzaboni, B., Weir, G. C. & Yankner, B. A. (1994) Nature (London) 368, 756-760]. The fibrils themselves are relatively resistant to proteolysis in vitro but amyloid deposits do regress in vivo, usually with clinical benefit, if new amyloid fibril formation can be halted. Serum amyloid P component (SAP) binds to all types of amyloid fibrils and is a universal constituent of amyloid deposits, including the plaques, amorphous amyloid beta protein deposits and neurofibrillary tangles of Alzheimer disease [Coria, F., Castano, E., Prelli, F., Larrondo-Lillo, M., van Duinen, S., Shelanski, M. L. & Frangione, B. (1988) Lab. Invest. 58, 454-458; Duong, T., Pommier, E. C. & Scheibel, A. B. (1989) Acta Neuropathol. 78, 429-437]. Here we show that SAP prevents proteolysis of the amyloid fibrils of Alzheimer disease, of systemic amyloid A amyloidosis and of systemic monoclonal light chain amyloidosis and may thereby contribute to their persistence in vivo. SAP is not an enzyme inhibitor and is protective only when bound to the fibrils. Interference with binding of SAP to amyloid fibrils in vivo is thus an attractive therapeutic objective, achievement of which should promote regression of the deposits.     

Ribosomal DNA internal transcribed spacer sequences do not support the species status of Ampelomyces quisqualis, a hyperparasite of powdery mildew fungi

Amyloid P component (AP) and apolipoprotein E (Apo E), which are known to be minor constituents of amyloid deposits, commonly are associated with almost all types of amyloid deposits. In this study, the distribution of AP-, Apo E- and ubiquitin (Ub)-immunoreactivity (IR) in amyloid deposits in the liver and spleen of human systemic amyloidosis (34 autopsy cases: 17 immunoglobulin light chain derived, 17 amyloid A protein derived) and experimental murine amyloidosis is examined using an immuno-histochemical technique. In human cases, all of the amyloid deposits examined showed colocalization of AP- and Apo E-IR with individual amyloid proteins. In experimental amyloidosis, AP-IR of amyloid deposits in the liver and spleen and Apo E-IR in the liver were seen uniformly throughout this experiment. In contrast, Apo E-IR in the spleen was not uniform at the phase of amyloid deposition. At 4 weeks and at 16 weeks after casein injection, Apo E-IR was unevenly distributed in amyloid deposits in the perifollicular area; however, from 6 to 12 weeks it was seen to be uniform. Ubiquitin-IR of amyloid deposits in human cases was seen in 22 of 34 livers and in 22 of 33 spleens. In experimental amyloidosis, Ub-IR of amyloid deposits was demonstrated in the space of Disse in all mice examined, and there appeared to be a gradual increase in intensity with the amount of amyloid deposition. However, in the spleen, amyloid deposits did not react with anti-Ub antibody in any phase of amyloid induction. These results suggest that Apo E and Ub are not always associated with the process of amyloid deposition and may appear in a deposit after the deposition.     

Localizations and consequences

The symptoms of amyloidosis depend on the type of precursor, the amount of deposits and their location. In systemic amyloidosis almost every organ may be involved. Cardiac involvement is severe, especially in AL amyloidosis, responsible for restrictive cardiomyopathy with right ventricular failure, leading rapidly to death. Renal amyloid deposition causes nephrotic syndrome with hypertension and renal failure. Neurological complications include peripheral neuropathy with dysautonomia cerebral involvement (dementia, cerebral haemorrhages). Arterial deposits are common in systemic senile amyloidosis, and may cause ischaemia. Osteo-articular damage is mainly seen in patients on long-term haemodialysis. Liver enlargement is often the only manifestation of hepatic amyloidosis. Digestive tract involvement includes macroglossia deposits in salivary glands and disturbances in gastrointestinal motility. Pulmonary amyloidosis causes nodular or interstitial infiltrates. Cutaneous lesions are various. Localized amyloidoses include goiter, breast and vesical involvement which can be difficult to differentiate from neoplasm, as well as ocular amyloidosis mimicking posterior uveitis.     

Amyloid precursor protein (APP) in the striatum in Alzheimer's disease: an immunohistochemical study

Increasing recognition of diffuse plaques has raised questions about the differences between diffuse and neuritic plaques, particularly in regard to the role of amyloid precursor protein (APP) processing in their formation. To address this issue, corpus striatum (containing almost exclusively diffuse plaques) and cerebral cortex (containing an admixture of plaque types) from patients with Alzheimer's disease (AD) were examined immunohistochemically with antibodies to domain-specific sites of APP (N-terminal, C-terminal, beta A4-related, isoform-specific, and other epitopes). Striatal plaques labeled strongly with beta A4 antibodies as did cortical plaques in AD and the occasional diffuse plaques in cortex from nondemented elderly controls. Weak labeling of some cortical neuritic plaques but not diffuse plaques was observed with antibodies directed against other APP epitopes. Electron microscopy of diffuse plaque-rich striatum in AD cases revealed only rare degenerating neurites without apparent fibrillar amyloid; no changes were noted in the plaque-free striatum of controls. These results suggest that antibodies to beta A4 recognize not only fibrillar amyloid of neuritic plaques but also antigenic determinants of diffuse plaques which lack fibrillar amyloid. Furthermore, the finding that antibodies to non-A4 domains of APP labeled only cortical but not striatal plaques suggests that APP processing mechanisms in cortical and striatal tissues may differ.     

Primary amyloidosis--involving principally intrarenal blood vessels

We analysed renal biopsies from 34 nephrotic patients with renal amyloidosis, seven with primary form kappa chain (AL amyloidosis) and 27 with secondary amyloidosis associated with the other chronic diseases. Renal biopsy specimens were analysed using optical and immunofluorescence microscopy. The extent of amyloid deposits was graded from 0 to + + + +. Intrarenal blood vessel deposits were more prominent than intraglomerular in five of seven patients with AL amyloidosis, while they were identical in one, and in one, intraglomerular amyloid deposits were dominant. The results were different in the group of patients with secondary amyloidosis: a lower degree of intrarenal blood vessels deposition than glomerular was noted in 22 of 27 cases, the degree of deposition was identical in 4 of 27 cases and more expressed blood vessel deposition was present in only one case. Granular or combined deposits (granular+linear) were found on immunofluorescence microscopy in primary form, but the dominant form of deposition was amorphous in secondary amyloid.     

Abundance of the longer A beta 42 in neocortical and cerebrovascular amyloid beta deposits in Swedish familial Alzheimer's disease and Down's syndrome

Recent studies have demonstrated the deposition of amyloid beta (A beta) protein with carboxyl- and aminoterminal heterogeneity in cortical and cerebrovascular deposits of Alzheimer's disease (AD). Using carboxyl end-terminal specific antibodies to A beta peptides, we examined the immunocytochemical distribution of A beta 40 and A beta 42 species in brain tissue from a Swedish subject with familial AD (FAD) bearing the double mutation at codons 670/671 in the amyloid beta precursor protein (A beta PP), and from subjects with Down's syndrome and sporadic AD. In the Swedish subject, we found profound parenchymal A beta deposits and cerebral amyloid angiopathy in all four cortical lobes and cerebellum. A beta 42 was evident in almost all parenchymal deposits as well as many vascular deposits. Although A beta 40 was present in meningeal and intraparenchymal vessels, deposits containing this shorter peptide reactivity were sparse. Surprisingly, our observations in Swedish FAD showing a remarkable abundance of A beta 42 in both parenchymal and vascular deposits were qualitatively similar to the Down's syndrome and most sporadic AD cases, and to previously published A beta PP717 FAD. While previous transfection studies in different cell cultures indicate substantially increased soluble A beta production and A beta 40 species to be predominant, it would appear that the double A beta PP mutations in Swedish FAD largely result in the deposition of the longer A beta 42 in vivo.     

Respiratory-chain and pyruvate metabolism defects: Italian collaborative survey on 72 patients

Cerebral amyloid angiopathy (CAA) is a neuropathological feature of Alzheimer's disease and a common cause of cerebral hemorrhage in the elderly. The pathogenetic mechanisms leading to the deposition of Alzheimer amyloid beta-protein (A beta) in cortical and leptomeningeal vessel walls are unknown. There are no experimental models which reproduce the pathological changes of CAA. In this study, leptomeninges from young and old dogs with pre-existing CAA were cultured in cell culture medium or cerebrospinal fluid and their viability, histological appearance and metabolic activity were analyzed during the culture. In addition, living leptomeninges of old and young dogs were incubated with fluorescein-conjugated A beta and the uptake of A beta was studied by fluorescence microscopy. Leptomeninges from young and old dogs were viable up to 8 weeks in culture. They contain many small- and medium-sized arterioles, the main vessel type affected by CAA. Histology and immunohistochemistry showed excellent preservation of the vessel wall microarchitecture up to 4 weeks in culture. The cultures were metabolically active as shown by the de novo production of beta-amyloid precursor protein. Exogenously added A beta was focally deposited in the vessel walls of old, but not young dogs. In conclusion, the organ culture of canine leptomeninges is easy to perform and appears suitable to investigate the pathogenesis and the progression of CAA.     

Amyloidosis: a review of recent diagnostic and therapeutic developments

Amyloid deposition is associated with a diverse range of disorders that includes Alzheimer's disease, type II diabetes mellitus and dialysis arthropathy. Although less common, systemic AA and AL amyloidosis remain important because effective treatments have increasingly become available. The pathology in all forms of amyloidosis involves the extracellular deposition of protein as characteristic fibrillar aggregates which interfere with tissue structure and function. Amyloid fibrils are derived from different unrelated proteins in the different forms of the disease but share many common properties, including the capacity to bind the normal plasma protein serum amyloid P component (SAP). This is the basis for our development of radiolabelled SAP as a nuclear medicine tracer for the diagnosis and quantitative monitoring of amyloid. Serial studies have shown that the deposits are far from inert but are actually turned over quite rapidly in many patients. The treatment of amyloidosis involves supportive measures whilst every effort is made to reduce the supply of the respective fibril precursor protein. Under favourable circumstances further amyloid deposition will be prevented. existing deposits will regress and improvement of organ function will occur. Since this strategy is not always possible or may fail, new approaches to inhibit fibril formation and promote regression of amyloid are being pursued.     

Use of immunoplot analysis for the identification of immunodominant non-variant antigens of Trypanosoma brucei rhodesiense

BACKGROUND: Common elements in many different types of amyloid may have important roles in amyloidogenesis. The proteinaceous tissue deposits have a common appearance in polarized light and other similar features. The present investigation describes for the first time the relation between beta 2-microglobulin (beta 2-M)-type amyloidosis and colocalized materials, as demonstrated using specific antibodies and hyaluronan-binding protein. EXPERIMENTAL DESIGN: Amyloid-rich carpal tunnel synovium was obtained surgically from 28 patients who were being treated by maintenance hemodialysis. Serial sections were examined using a hyaluronan (hyaluronic acid)-binding protein and antibodies against heparan sulfate-glycosaminoglycan, chondroitin sulfate-proteoglycan, dermatan sulfate-proteoglycan, alpha 1-antichymotrypsin, alpha 1-antitrypsin, inter-alpha-trypsin inhibitor, haptoglobin, and ubiquitin. RESULTS: Accumulation of hyaluronan was of three types, namely, localization around beta 2-M deposits, colocalization with deposition of beta 2-M itself and localization at a small distance from beta 2-M deposits. Immunostaining for heparan sulfate glycosaminoglycan was demonstrated at the sites of beta 2-M plaques. Chondroitin sulfate-proteoglycan did not show specific patterns of immunostaining, resembling hyaluronan rather than heparan sulfate. The other materials tested, alpha 1-antichymotrypsin, alpha 1-antitrypsin, inter-alpha-trypsin, haptoglobin and ubiquitin, were not immunostained at sites of beta 2-M plaques. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting revealed that the molecular weight of heparan sulfate-glycosaminoglycan was 16,000. CONCLUSIONS: These results suggest that HS has an important role in hemodialysis-associated amyloidosis as it does in other types of amyloidosis. Moreover, accumulation of hyaluronan may be an indication of inflammation of the carpal synovium.     

Determination of the frequency and distribution of vascular and parenchymal amyloid with polyclonal and N-terminal-specific PrP antibodies in scrapie-affected sheep and mice

Brains from 17 histopathologically confirmed cases of scrapie, five of which had congophilic vascular amyloid, were stained immunohistochemically for prion protein (PrP) using a polyclonal antibody. Two clinically suspect but pathologically unconfirmed cases of natural sheep scrapie and the brains of four mice infected with the 111A murine scrapie strain were also examined. Selected sections containing amyloid were stained with each of two peptide antibodies which recognise the N-terminal amino acid residues which are lost following protease digestion of the disease-specific isoform of PrP. The mice infected with the 111A murine scrapie strain had large numbers of hypermature plaques. All the amyloid plaques from both natural sheep scrapie brains and experimental murine brains were heavily immunostained by the polyclonal and both peptide antibodies. In addition, disease-specific accumulations of PrP were detected in endothelial cells or in the intima of blood vessels of the cerebral cortex of sheep scrapie brains. The affected blood vessels were located in areas which otherwise lacked typical scrapie pathology. Vascular accumulations of PrP were also found in leptomeningeal and choroid plexus blood vessels. Vascular amyloid was found mainly in the neocortex. Vascular amyloid and disease-specific parenchymal accumulations of PrP were found in two sheep which showed clinical signs of scrapie but lacked its typical vacuolar pathology. These results show that the mature amyloid of scrapie is composed of, or contains a substantial proportion of, whole length PrP protein. Thus truncation of PrP is not essential for the aggregation of PrP into amyloid. The vascular amyloid of natural sheep scrapie originates from the accumulation and release of PrP from endothelial cells presumably following systemic scrapie infection. The topography of vascular amyloid distribution in Great Britain differs from that reported in the Netherlands. As amyloid deposition in mice is largely controlled by the strain of the infecting agent it is possible that the strain of the agent may influence vascular amyloid deposition.     

Alzheimer amyloid protein precursor in the rat hippocampus: transport and processing through the perforant path

Amyloid deposition is a neuropathological hallmark of Alzheimer's disease. The principal component of amyloid deposits is beta amyloid peptide (Abeta), a peptide derived by proteolytic processing of the amyloid precursor protein (APP). APP is axonally transported by the fast anterograde component. Several studies have indicated that Abeta deposits occur in proximity to neuritic and synaptic profiles. Taken together, these latter observations have suggested that APP, axonally transported to nerve terminals, may be processed to Abeta at those sites. To examine the fate of APP in the CNS, we injected [35S]methionine into the rat entorhinal cortex and examined the trafficking and processing of de novo synthesized APP in the perforant pathway and at presynaptic sites in the hippocampal formation. We report that both full-length and processed APP accumulate at presynaptic terminals of entorhinal neurons. Finally, we demonstrate that at these synaptic sites, C-terminal fragments of APP containing the entire Abeta domain accumulate, suggesting that these species may represent the penultimate precursors of synaptic Abeta.     

Development of gastrointestinal beta2-microglobulin amyloidosis correlates with time on dialysis

Dialysis-associated beta2-microglobulin (beta2m) amyloidosis affects predominantly musculoskeletal tissue, but visceral involvement also occurs. To evaluate the clinical significance and prevalence of gastrointestinal beta2m amyloidosis, we studied hemodialysis patients admitted for gastrointestinal-related complaints. Hemodialysis patients (excluding those with non-beta2m amyloidosis) who were admitted with gastrointestinal complaints from 1984 to 1994 were identified. Gastrointestinal tissues from patients with available autopsy or surgical specimens were examined using hematoxylin and eosin stain, Congo red stain, and beta2m immunostain. Each case was evaluated independently by two pathologists and scored for quantity and location of beta2m amyloid and associated pathology. Of 24 patients, eight (four men and 4 women) had beta2m amyloid deposits within the gastrointestinal tract. Acute clinical presentation ranged from abdominal pain to gastrointestinal bleeding and was not significantly different for patients with or without gastrointestinal beta2m amyloid deposits. However, the mean time on dialysis of 15.3 +/- 5.7 years (range 6-24 years) for patients with gastrointestinal beta2m amyloidosis was significantly greater than that of patients without gastrointestinal beta2m amyloidosis (10.5 +/- 7.0 years, range <1 to 22 years, p < 0.05). Vascular histopathology ranged from mild focal thickening of vessel walls to massive vascular beta2m amyloid deposition with thrombosis. Extravascular beta2m amyloid ranged from mild to severe with marked expansion of the submucosa. Mucosal pathology ranged from none to severe ulceration. The degree of beta2m amyloid and the associated pathology tended to increase in severity with time on dialysis. Gastrointestinal beta2m amyloid deposition is an underappreciated complication of chronic hemodialysis that is significantly associated with increased time on dialysis. Gastrointestinal beta2m amyloidosis should be considered in any patient on hemodialysis 10 years or more who has gastrointestinal symptoms and can be identified in resection specimens as well as some biopsy specimens. Congo red stain and beta2m immunostains may be necessary for sensitive histopathologic evaluation of gastrointestinal beta2m amyloidosis.     

Histopathological studies of senile plaques and cerebral amyloidosis in cynomolgus monkeys

Senile plaques (SPs) and cerebral amyloid angiopathy (CAA), pathological hallmarks of Alzheimer's disease, have not been thoroughly investigated histopathologically in nonhuman primates. To determine the onset age and histopathological characteristics of SPs and CAA, we examined the brains of 64 cynomolgus monkeys (Macaca fascicularis) from 2 to 35 years old. Mature (classical and primitive) plaques appeared in 16 out of 25 monkeys that were >20 years old. Moreover, mature plaques were observed more frequently than diffuse plaques and were located in the temporal cortex of the superior or inferior gyri and amygdala. Diffuse plaques in contrast to mature plaques did not show definite tendencies in onset age and distribution. CAA appeared in more than 22-year-old monkeys in 10 out of 16 animals and was frequently observed in capillaries and often found adjoining mature plaques. During immunohistochemical examination, an antiserum for amyloid beta protein (A beta) 1-40 could detect all SPs, whereas a monoclonal antibody for A beta 8-17 could not detect any diffuse plaques and only one third of the primitive plaques. As for CAA, the polyclonal antiserum was more sensitive than the monoclonal antibody. The present study describes the histopathological features of SPs and CAA in old cynomolgus monkeys.     

Diagnosis and treatment of postoperative chyle leakage via percutaneous transabdominal catheterization of the cisterna chyli: a preliminary study

BACKGROUND AND AIMS: The liver is frequently involved in amyloidosis but the significance of hepatic amyloid has not been systematically studied. We have previously developed scintigraphy with 123I serum amyloid P component (123I-SAP) to identify and monitor amyloid deposits quantitatively in vivo and we report here our findings in hepatic amyloidosis. METHODS: Between 1988 and 1995, 805 patients with clinically suspected or biopsy proven systemic amyloidosis were evaluated. One hundred and thirty eight patients had AA amyloidosis, 180 had AL amyloidosis, 99 had hereditary amyloid syndromes, and 67 had dialysis related (beta 2 microglobulin) amyloid. One hundred and ninety two patients with amyloidosis were followed for six months to eight years. RESULTS: Hepatic amyloid was found in 98/180 (54%) AL and 25/138 (18%) AA patients but in only 1/53 patients with familial transthyretin amyloid polyneuropathy and in none with dialysis related amyloidosis. There was complete concordance between hepatic SAP scintigraphy and the presence or absence of parenchymal amyloid deposits on liver histology. Amyloidosis was never confined to the liver. Mortality was rarely due to hepatic failure, although hepatic involvement with AA amyloid carried a poor prognosis. Successful therapy to reduce the supply of amyloid fibril protein precursors was followed by substantial regression of all types of amyloid. CONCLUSIONS: SAP scintigraphy is a specific and sensitive method for detecting and monitoring hepatic amyloid. Liver involvement is always associated with major amyloid in other organ systems and carries a poor prognosis in AA type. Appropriate therapy may substantially improve prognosis in many patients.