Deposition Of Amorphous Material Research Articles

Immunohistochemical typing of amyloid in fixed paraffin-embedded samples by an automatic procedure: Comparison with immunofluorescence data on fresh-frozen tissue.

Amyloidosis comprises a spectrum of disorders characterized by the extracellular deposition of amorphous material, originating from an abnormal serum protein. The typing of amyloid into its many variants represents a pivotal step for a correct patient management. Several methods are currently used, including mass spectrometry, immunofluorescence, immunohistochemistry, and immunogold labeling. The aim of the present study was to investigate the accuracy and reliability of immunohistochemistry by means of a recently developed amyloid antibody panel applicable on fixed paraffin-embedded tissues in an automated platform. Patients with clinically and pathologically proven amyloidosis were divided into two cohorts: a pilot one, which included selected amyloidosis cases from 2009 to 2018, and a retrospective one (comprising all consecutive amyloidosis cases analyzed between November 2018 and May 2020). The above-referred panel of antibodies for amyloid classification was tested in all cases using an automated immunohistochemistry platform. When fresh-frozen material was available, immunofluorescence was also performed. Among 130 patients, a total of 143 samples from different organs was investigated. They corresponded to 51 patients from the pilot cohort and 79 ones from the retrospective cohort. In 82 cases (63%), fresh-frozen tissue was tested by immunofluorescence, serving to define amyloid subtype only in 30 of them (36.6%). On the contrary, the automated immunohistochemistry procedure using the above-referred new antibodies allowed to establish the amyloid type in all 130 cases (100%). These included: ALλ (n = 60, 46.2%), ATTR (n = 29, 22.3%), AA (n = 19, 14.6%), ALκ (n = 18, 13.8%), ALys (n = 2, 1.5%), and Aβ2M amyloidosis (n = 2, 1.5%). The present immunohistochemistry antibody panel represents a sensitive, reliable, fast, and low-cost method for amyloid typing. Since immunohistochemistry is available in most pathology laboratories, it may become the new gold standard for amyloidosis classification, either used alone or combined with mass spectrometry in selected cases.

Cutaneous collagenous vasculopathy: light and transmission electron microscopy

Cutaneous collagenous vasculopathy is a rare acquired idiopathic microangiopathy characterized by progressive development of diffuse asymptomatic telangiectasias and histologically by accumulation of collagen type IV around the affected vessels. It is diagnosed by its clinical history, confirmed by light microscopy with collagen-specific immunostaining. We report a case of a patient with extensive acquired telangiectasias on the left arm, clinically resembling unilateral nevoid telangiectasia. Dilated blood vessels with thickened walls were observed in the dermis. Immunohistochemistry with collagen IV antibodies revealed marked collagen deposition around the vessels, confirming the diagnosis. Transmission electron microscopy observed duplicate and triplicate vascular basal membrane associated with deposition of amorphous material around the membranes.

Medical renal diseases are frequent but often unrecognized in adult autopsies

Kidney diseases affect many hospitalized patients and contribute to morbidity and mortality. Therefore, kidney disease should be prevalent, but the frequency and spectrum of medical renal pathology in autopsy specimens has not been well documented. We sought to determine the spectrum of medical renal pathology in adult autopsy specimens and the frequency of overlooked diagnoses. We reviewed the hematoxylin- and eosin-stained kidney sections from 140 adult autopsies performed at a large teaching hospital over a 2-year period. Fifty-eight cases (41%) had findings warranting further analysis, including alterations in glomerular matrix and/or cellularity, atypical or pigmented casts, thrombi, tubulointerstitial or vascular inflammation, or deposition of amorphous material. After additional studies and clinical correlation, the pathologic changes in 43 cases (31%) were categorized as follows: diabetic nephropathy, bile cast nephropathy, thrombotic microangiopathy, infection-related glomerulonephritis, focal necrotizing/crescentic glomerulonephritis, oxalate nephropathy, light-chain cast nephropathy, amyloidosis, urate nephropathy, hemosiderosis, antineutrophil cytoplasmic antibody-associated vasculitis, polyoma virus nephropathy, atheroembolic disease, and nephrocalcinosis. These diagnoses were not reported in 26 (60%) cases during the initial autopsy evaluation. This study demonstrates that medical renal diseases are common in autopsy cases, but significant diagnoses can be easily overlooked. Autopsy kidney specimens are a rich source of renal pathology and their evaluation should be emphasized in anatomic pathology residency training. Ultimately, our understanding of how kidney disease contributes to morbidity and mortality will benefit from accurate recognition of renal pathology in autopsy specimens.

Tracheobronchial Amyloidosis Mimicking Tracheal Tumor.

Tracheobronchial amyloidosis is a rare presentation and accounts for about 1% of benign tumors in this area. The diagnosis of disease is delayed due to nonspecific pulmonary symptoms. Therapeutic approaches are required to control progressive pulmonary symptoms for most of the patients. Herein, we report a case of a 68-year-old man admitted with progressive dyspnea to our institution for further evaluation and management. He was initially diagnosed with and underwent management for bronchial asthma for two years but had persistent symptoms despite optimal medical therapy. Pulmonary computed tomography scan revealed severe endotracheal stenosis. Bronchoscopy was performed and showed endotracheal mass obstructing 70% of the distal trachea and mimicking a neoplastic lesion. The mass was successfully resected by mechanical resection, argon plasma coagulation (APC), and Nd-YAG laser during rigid bronchoscopy. Biopsy materials showed deposits of amorphous material by hematoxylin and eosin staining and these deposits were selectively stained with Congo Red. Although this is a rare clinical condition, this case indicated that carrying out a bronchoscopy in any patient complaining of atypical bronchial symptoms or with uncontrolled asthma is very important.

Formation of pure Cu nanocrystals upon post-growth annealing of Cu-C material obtained from focused electron beam induced deposition: comparison of different methods.

In this paper we study in detail the post-growth annealing of a copper-containing material deposited with focused electron beam induced deposition (FEBID). The organometallic precursor Cu(II)(hfac)2 was used for deposition and the results were compared to that of compared to earlier experiments with (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB). Transmission electron microscopy revealed the deposition of amorphous material from Cu(II)(hfac)2. In contrast, as-deposited material from (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB) was nano-composite with Cu nanocrystals dispersed in a carbonaceous matrix. After annealing at around 150–200 °C all deposits showed the formation of pure Cu nanocrystals at the outer surface of the initial deposit due to the migration of Cu atoms from the carbonaceous matrix containing the elements carbon, oxygen, and fluorine. Post-irradiation of deposits with 200 keV electrons in a transmission electron microscope favored the formation of Cu nanocrystals within the carbonaceous matrix of freestanding rods and suppressed the formation on their surface. Electrical four-point measurements on FEBID lines from Cu(hfac)2 showed five orders of magnitude improvement in conductivity when being annealed conventionally and by laser-induced heating in the scanning electron microscope chamber.

Primary amyloidosis-induced nail dystrophy

Primary amyloidosis is caused by a monoclonal proliferation of plasma cells and is capable of producing cutaneous lesions. A 56-year-old male was admitted to the hospital for evaluation of chronic back pain and acute lower extremity weakness. On examination, he was noted to have subungual verrucous plaques with overlying nail dystrophy on his bilateral thumbs. A biopsy of one subungual lesion showed a deposition of amorphous material in the dermis that stained with Congo red and crystal violet. These cutaneous lesions ultimately led to the diagnosis of plasma cell dyscrasia and primary amyloidosis. Based on the literature search, primary amyloidosis presenting with this degree of subungual thickening and overlying nail dystrophy has not been previously reported.

Mice With a Targeted Disruption ofSlc4a11Model the Progressive Corneal Changes of Congenital Hereditary Endothelial Dystrophy

To establish an animal model of congenital hereditary endothelial dystrophy (CHED) using Slc4a11 knockout (KO) mice and evaluate the abnormalities in the cornea and kidney. The Slc4a11 KO mouse model was generated by gene deletion. Corneal abnormalities were evaluated using slit-lamp photography, anterior segment optical coherence tomography (AS-OCT), immunohistochemistry, RT-PCR, corneal endothelial cell staining, and electron microscopy. The temporal corneal changes were also monitored. Histological and functional changes of the kidney were also evaluated. Successful knockout of the Slc4a11 gene was confirmed by immunohistochemistry and RT-PCR. Slit-lamp photography and AS-OCT showed progressive corneal edema. Increased corneal endothelial cell size with decreased corneal endothelial cell density was observed with increased age. Scanning electron microscopy also revealed progressive cell swelling and distortion of the hexagonal cell morphology with time. Transmission electron microscopy showed characteristic ultrastructural findings of CHED, including endothelial vacuolization, thickening of the Descemet membrane, disorganization of collagen fibril, deposition of amorphous material, and progression of these changes with age. Decreased urine osmolarity and electrolyte concentrations suggesting abnormality in water resorption were also detected. Our Slc4a11 KO mouse model successfully represents clinical manifestations of human CHED. We were able to show chronological corneal progression for the first time in a knockout mouse model as well as renal abnormalities.

Renal biopsy is a helpful tool for the diagnosis of POEMS syndrome

A 57-year-old Japanese male was admitted to our hospital for pleural effusion, massive ascites, and leg edema in March 2010. Upon physical examination, hyperpigmentation, hemangioma, and gynecomastia were noted. The patient had no neurological symptoms, but tendon reflexes were absent. Urinalysis showed 2 proteinuria and 2 hematuria. Chest radiograph showed cardiomegaly and bilateral pleural effusion. Computed tomography of the abdomen revealed hepatosplenomegaly, and massive ascites. Blood examination showed moderate renal dysfunction (serum creatinine 1.81 mg/dl, blood urea nitrogen 44 mg/ dl). A small amount of monoclonal protein was detected, and serum protein immunoelectrophoresis revealed this to be IgA-k M protein (1295 mg/dl). There were 5.4 % plasma cells in bone marrow aspirate and biopsy, but hematopoiesis was otherwise normal. The low concentration of M protein was unusual for multiple myeloma, and examination of the bone marrow did not reveal neoplastic plasma cell. Moreover, there were no plasmacytomas. Systematic amyloidosis, the result of deposition of abnormal light chain in tissues was considered. To develop a definitive diagnosis, percutaneous renal biopsy was performed, revealing enlarged glomeruli with mild proliferation of mesangial cells and segmental mesangiolysis. This glomerular alteration resembled membranoproliferative glomerulonephritis (MPGN) in appearance (Fig. 1a). Electron microscopy showed widening of the subendothelial and mesangial area, with widespread deposition of amorphous material (Fig. 1b), histological findings consistent with the typical histology of POEMS syndrome. After the renal biopsy, POEMS syndrome was suspected and his massive ascites was thought to be due to this syndrome. Plasma VEGF level was elevated (700 pg/ml; normal \117 pg/ml). Motor nerve conduction studies performed in the median nerve showed mild decrease in the nerve conduction velocities. The association of polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes led to the diagnosis of POEMS syndrome. The patient had three major criteria (including two mandatory) and five minor criteria of the current Mayo Clinic criteria for the diagnosis of POEMS syndrome [1]. Here, we report a patient with POEMS syndrome whose renal biopsy led us to an appropriate diagnosis. In POEMS syndrome, the presenting symptoms are variable and sometimes difficult to diagnose. POEMS syndrome is also known to show unique features in renal biopsy, such as MPGN-like lesions and mesangiolytic glomerulonephritis. Electron-lucent subendothelial space in glomerular capillaries by electron microscopy has been found to be a characteristic feature in POEMS syndrome [2]. Our experience in this case indicates that renal biopsy may be helpful for the diagnosis of POEMS syndrome.

Ultrastructural and cytochemical studies on oogenesis of the fern Pteridium aquilinum

Egg development in Pteridium aquilinum var. latiusculum was studied using ultrastructural and cytochemical methods to examine structural features influencing fertilization in leptosporangiate ferns. Ultrastructural observations indicate a separation cavity is first formed above the egg during oogenesis with a pore region persistently connecting the egg and the ventral canal cell. The egg envelope is formed by deposition of amorphous materials in the separation cavity on the outer surface of plasmalemma. The egg envelope was not formed across the pore region; instead, a fertilization pore was formed. During oogenesis, the egg nucleus produced extensive evaginations containing osmiophilic bodies. Cytochemical experiments revealed that the egg envelope displays strong periodic acid-Schiff reaction indicative of polysaccharides, with negligible Sudan black B staining for lipids, suggesting that the egg envelope is composed principally of polysaccharides, and not lipids. The present manuscript provides new insights into egg structure and development of Pteridium, including discovery and characterization of the fertilization pore and observations on the chemical nature of the egg envelope, thus contributing to the understanding of the cytological mechanism of the sexual reproduction of ferns.

Ultrastructure of the Anterior Lens Capsule and Epithelium in Cataracts Associated with Uveitis

Aims: To study the ultrastructure of the anterior lens capsule and epithelium, and capsular thickness in uveitic cataracts. Methods: Capsulorhexis samples from 20 uveitic cataracts were compared to 20 nuclear cataracts using the semi- and ultra-thin techniques. Results: Extensive epithelial and capsular-epithelial border changes and epithelial-mesenchymal transition in some fibrotic capsules were found only in the uveitic group. All these changes were observed predominately in white uveitic cataracts. Mild and moderate ultrastructural changes were seen in both groups. Surface deposition of amorphous material was also found only in uveitic cataracts. Capsular thickness was not different between the two groups. Conclusions: Uveitic capsules showed more extensive and different ultrastructural changes that probably occurred because of inflammation in the eye and epithelial-mesenchymal transition. These changes might be an additional reason for altered behavior of the lens capsule at capsulorhexis.

Nephrotoxicity caused by brown spider venom phospholipase-D (dermonecrotic toxin) depends on catalytic activity

Bites from brown spiders ( Loxosceles genus) have clinical manifestations including skin necrosis with gravitational spreading, and systemic involvement that may include renal failure, hemolysis, and thrombocytopenia. Mice were exposed to recombinant wild-type phospholipase-D, or to an isoform with a mutation in the catalytic domain resulting in no phospholipasic activity. Renal biopsies from mice treated with the wild-type toxin showed glomerular edema, erythrocytes and collapse of Bowman's space, edema and deposition of proteinaceous material within the tubular lumen. Ultrastructural analyses confirmed cytotoxicity by demonstrating disorders of glomerulus at foot processes and at fenestrated endothelium. Tubule alterations include deposits of amorphous material and edema, as well as an increase of epithelial cytoplasmic multivesicular bodies and electron-dense structures. There was an absence of nephrotoxicity in mice treated with the mutated toxin. Analyses of urine and blood showed that wild type toxin induced hematuria and elevation of blood urea, while treatment with mutated toxin caused no changes. Mouse lethality experiments also showed oliguria and mortality after treatment with wild-type toxin, but not following exposure to the mutated toxin. Immunofluorescence using antibodies to phospholipase-D toxin showed deposition of both toxins along the renal tubular structures as detected by confocal microscopy. Immunoblots of urine showed a 30 kDa band in samples from animals treated with wild-type toxin, but no band from mice exposed to mutated toxin. Wild-type toxin treatment caused cytoplasmic vacuolization, impaired spreading, reduction of cellular viability, and cell–cell and cell–substratum detachment in MDCK cells, while treatment with mutated isoform had no effect. Finally, there is a direct correlation between toxin activity on cell membrane phospholipids generating choline and cytotoxicity. We have defined for the first time a molecular mechanism for Loxosceles venom nephrotoxicity that is dependent on the catalytic activity of phospholipase-D toxin.

Homozygous Transthyretin Mutation in an African American Male

Cardiac amyloidosis of transthyretin type in the elderly may be senile or familial. The senile form is not typically associated with specific genetic changes. However, the familial form is and also occurs more frequently in African Americans than in the general population. One transthyretin mutation, V122I, is common in the African-American population, has a carrier frequency of 4%, and has marked cardiac specificity. Symptoms generally develop in the eighth and ninth decades. Here, we report the case of a 60-year-old African-American man who had a 2-year history of dyspnea and diffuse left ventricular wall thickening. Endomyocardial biopsy showed interstitial deposits of amorphous material confirmed as amyloid by Congo red staining and electron microscopy. Mass spectrometry showed a shift in protein mass of 14 d, indicative of transthyretin and confirming the production of abnormal protein. Bidirectional whole gene sequencing showed a homozygous mutation leading to a valine 122 isoleucine substitution (V122I). The 14-d mass shift observed using mass spectrometry is consistent with the V122I mutation. Homozygosity for the V122I mutation may be associated with earlier onset of cardiac disease. Transthyretin analysis should be considered for older African Americans with amyloid heart disease of transthyretin type.

Early atherosclerotic lesions of the cardiac conduction system arteries in infants

Introduction Although several studies have described initial atherosclerotic lesions of the coronary arteries, already detectable in infancy and even during the intrauterine life, little, if any, attention has been given to the possible involvement of the cardiac conduction system arteries. In particular, to the best of our knowledge, none has considered the lesions of the cardiac conduction arteries as an initial stage of atherosclerosis. Methods The cardiac conduction system of 70 infants dying suddenly and unexpectedly was removed in two blocks for paraffin embedding and serially cut. Results The histological study of the cardiac conduction arteries of the 70 cases examined showed a normal structure in 55 cases (78.57%). In 15 cases (21.43%), there was a thickening of the sinoatrial node and/or atrioventricular artery associated with a thickening of varying severity in coronary artery walls. The lesions were marked by thickening and deposits of amorphous material and mainly lipids in the intima, as well as fragmentation of the elastic fiber system. A significant correlation was evident between early atherosclerotic lesions and both formula feeding and parental cigarette smoking ( P<.05, χ 2 test). Conclusions The combination of both the considered risk factors seems to increase the early atherogenic effect of each noxa because the coronary lesions were more diffused in formula-fed infants whose parents both smoked.

Experimental evidence for a direct cytotoxicity of Loxosceles intermedia (brown spider) venom in renal tissue.

Brown spider (Loxosceles genus) venom causes necrotic lesions often accompanied by fever, hemolysis, thrombocytopenia, and acute renal failure. Using mice exposed to Loxosceles intermedia venom, we aimed to show whether the venom directly induces renal damage. The experimental groups were composed of 50 mice as controls and 50 mice that received the venom. Light microscopic analysis of renal biopsy specimens showed alterations including hyalinization of proximal and distal tubules, erythrocytes in Bowman's space, glomerular collapse, tubule epithelial cell blebs and vacuoles, interstitial edema, and deposition of eosinophilic material in the tubule lumen. Electron microscopic findings indicated changes including glomerular epithelial and endothelial cell cytotoxicity as well as disorders of the basement membrane. Tubule alterations include epithelial cell cytotoxicity with cytoplasmic membrane blebs, mitochondrial changes, increase in smooth endoplasmic reticulum, presence of autophagosomes, and deposits of amorphous material in the tubules. We also found that the venom caused azotemia with elevation of blood urea levels but did not decrease C3 complement concentration or cause hemolysis in vivo. Confocal microscopy with antibodies against venom proteins showed direct binding of toxins to renal structures, confirmed by competition assays. Double-staining immunofluorescence reactions with antibodies against type IV collagen or laminin, antibodies to venom toxins, and fluorescent cytochemistry with DAPI revealed deposition of toxins in glomerular and tubule epithelial cells and in renal basement membranes. Two-dimensional electrophoresis showed venom rich in low molecular mass and cationic toxins. By immunoblotting with antibodies to venom toxins on renal extracts from venom-treated mice, we detected a renal binding toxin at 30 kD. The data provide experimental evidence that L. intermedia venom is directly involved in nephrotoxicity.

Development of thecal plates and pellicle in the dinoflagellate Scrippsiella hexapraecingula (Peridiniales, Dinophyceae) elucidated by changes in stainability of the associated membranes

The development of the pellicle and thecal plates of the dinoflagellate Scrippsiella hexapraecingula Horiguchi et Chihara was investigated with particular emphasis on cellulose synthesis. In young motile cells, incipient thecal plates appear as several groups of granular material within individual sites that are thought to be amphiesmal vesicles and develop into thin, sheet-like plates. These plates subsequently thicken with the deposition of amorphous material and cellulose microfibrils to form mature thecal plates. After ecdysis, non-motile cells form a pellicle consisting of three layers, L1-3. L1 is electron dense, while L2 and L3 are electron transparent. L1 and L2 are non-cellulosic, but L3 contains cellulose microfibrils. A new type of putative cellulose-synthesizing enzyme complex was found in non-motile cells. It consists of two rows of particles occurring on the plasmatic fracture face of the plasma membrane and begins to appear 0.5 – 1 h after ecdysis. The periodic acid-thiocarbohydrazide-silver proteinate test (PATAg) strongly stains the plasma membrane in both motile and non-motile cells throughout most of the life cycle of this species. The only time when it does not stain the plasma membrane is during an approximately 1-h period following ecdysis. During this period, the plasma membrane stains strongly with a silicotungstic acid-chromic acid mixture (STA-CA). STA-CA also stains the inner membranes of amphiesmal vesicles in both motile and non-motile cells. Thus, changes in the ability of PATAg and STA-CA to stain membranes during development suggest that the plasma membrane in non-motile cells is undergoing transformation after ecdysis.

Frequent association between MEN 2A and cutaneous lichen amyloidosis.

Multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid carcinoma (FMTC) are genetic diseases due to activating mutations of the RET proto-oncogene. Affected patients develop medullary thyroid carcinoma (100%), in an isolated form (FMTC) or in association with phaeochromocytoma (30-50%), and primary hyperparathyroidism (10-20%) (MEN 2A). The presence of cutaneous lichen amyloidosis (CLA) has been anecdotally described in few families harbouring RET proto-oncogene mutation in codon 634. The aim of the study was to evaluate the incidence of CLA in MEN 2A/FMTC families. Ten MEN 2A/FMTC families were studied and RET gene mutations identified in all. Complete dermatological assessment was carried out in each family member. Skin biopsy for histological studies was performed in patients with CLA. Among 10 MEN 2A/FMTC families, the presence of CLA was found only in patients belonging to the three families with MEN 2A and RET mutation in codon 634. Nine of 25 patients (36%) with codon 634 mutation presented CLA, though two of them did not show CLA skin lesions but the typical neurological pruritus in the upper back. In all patients, neurological pruritus was present since infancy as a precocious marker of the disorder. The dermatological study of patients with CLA skin lesions added further evidence that pruritus has a pivotal role in the development of CLA, the amyloid deposition being the consequence of repeated scratching. Light microscopy revealed orthokeratotic hyperkeratosis, with elongation of the rete ridges, rare intramalpighian apoptic keratinocytes and deposits of amorphous material in the superficial dermis. Examination under ultraviolet light showed thioflavin T-positive staining, confirming the presence of amyloid in the papillary dermis. The use of Capsaicin at the dilution of 0.025% had a mild efficacy on the cutaneous symptoms. Among the members of the three families with MEN 2A and RET 634 mutation, the incidence of CLA was 36%, a figure similar to that reported in the literature for phaeochromocytoma (30-50%) and even higher than that for hyperparathyroidism (10-20%). The present data confirm that CLA is linked to codon 634 RET mutations and is a precocious marker of the disorder.

Characterization of melanoma associated spongiform scleropathy.

Melanoma associated spongiform scleropathy (MASS) describes areas within the sclera where collagen bundles appear to have disintegrated into loose fibres. It is found adjacent to choroidal and ciliary body melanoma. This study aimed to characterize these changes histopathologically. Sections of 218 eyes that had been enucleated for malignant melanoma between January 1994 and June 2000 were examined for MASS, using data collected from the files of the Eye Pathology Institute, University of Copenhagen. Findings were correlated to patient characteristics (age, gender and pre-enucleation radiation) and tumour characteristics (location, morphology and invasion). Staining was applied using haematoxylin-eosin (HE), periodic acid-Schiff (PAS), haematoxylin-phloxine-saffron (HPS), alcian blue, colloidal iron and Masson's trichrome. Sixteen normal eyes and 29 eyes with diseases other than choroidal and ciliary body melanoma served as controls. Melanoma associated spongiform scleropathy was observed in 73 of the 218 eyes (33%) with melanoma. No changes were found in normal eyes or in eyes with other intraocular diseases. A significantly higher incidence of MASS was found in older age groups. Thirty-six (49%) of the 73 cases of MASS were observed within a patient age range of 71-90 years, whereas only 14 cases (19%) were observed within an age range of 41-60 years. Pre-enucleation radiation significantly reduced the incidence of MASS. Twenty-two (10%) of the total 218 eyes had received pre-enucleation radiation and in only two (1%) of these was MASS observed. Melanoma associated spongiform scleropathy was found only in areas of contact between the tumour and the sclera, and the degree of MASS correlated directly with the extent of this contact. No significant correlation with tumour cell type was found. In eyes with MASS, the severity of the changes correlated to the extent of direct contact between the tumour and sclera. Melanoma associated spongiform scleropathy showed a significant predilection towards older age groups. Pre-enucleation radiation significantly reduced the incidence of MASS. Melanoma associated spongiform scleropathy is probably caused by a deposition of amorphous material splitting the scleral collagen fibrils. This material may be secreted either directly from the adjacent tumour or from scleral fibroblasts stimulated by the tumour cells.

Extensive intraglomerular thrombi of monoclonal IgM-Κ in a patient with malignant lymphoma

We describe an 80-year-old man who developed malignant lymphoma (ML) complicated by extensive intraglomerular thrombi of immunoglobulin M (IgM)-Κ monoclonal immunoglobulin. The clinical picture was characterized by nephrotic syndrome and systemic lymphadenopathy. Laboratory examination showed mild anemia and a small amount of monoclonal IgM-Κ in the blood. The histopathologic findings and surface immunoglobulin analysis of the lymph node biopsy specimen were consistent with CD5-positive diffuse large B-cell (type, IgM-Κ) lymphoma. The subsequent renal biopsy showed a massive deposition of amorphous material in the glomerular capillary lumens, subendothelial areas, and mesangium. Nodular glomerulosclerosis was not found. An immunofluorescent study showed that the deposits consisted of IgM-Κ monoclonal immunoglobulin. Ultrastructurally, the deposits were composed of granular electron-dense material. Chemotherapy was effective for both the ML and nephrotic syndrome, and the patient's urine analysis results returned to normal. The histopathologic manifestations of this case are rare, and the pathogenesis of these glomerular lesions was obviously associated with ML.

Antifungal Activity of 2-Deoxy-D-Glucose on Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer: Ultrastructural and Cytochemical Aspects

ABSTRACT The effect of 2-deoxy-D-glucose on major postharvest pathogens was investigated at the ultrastructural and cytochemical level. Hyphae of Botrytis cinerea, Penicillium expansum,, and Rhizopus stolonifer grown in the absence of 2-deoxy-D-glucose were normal and showed no apparent cytological alterations. In the presence of 2-deoxy-D-glucose, however, these fungi exhibited severe cellular injuries ranging from cell wall disruption to cytoplasm disintegration. Although 2-deoxy-D-glucose caused cytoplasmic degeneration in the three fungi tested, cell wall alterations were exhibited only by B. cinerea and R. stolonifer. In the latter, the retraction of degenerated cytoplasm was often accompanied by the deposition of amorphous material in paramural spaces. Cytochemical study of fungal cell wall components showed that 2-deoxy-D-glucose caused a marked increase of chitin- and beta-1,3-glucan-labeling in R. stolonifer and B. cinerea, indicating an interference of 2-deoxy-D-glucose with fungal wall biosynthesis. The observed cellular alterations indicate that 2-deoxy-D-glucose may also have affected other metabolic processes.

The elastic system of a pressure-bearing tendon of thebullfrog Rana catesbeiana

Elastic system components have been described in the pressure-bearing tendon of the bullfrog, Rana catesbeiana, as a result of histochemical tests and transmission and scanning electron microscopy. The tension region was shown to possess microfibril bundles, some of which exhibited central deposits of amorphous material. The use of ANS-butanol plus fluorescence microscopy enormously facilitated the identification of elastic system components in both tension and compression regions of the frog tendon. The compression region exhibited pre-elastic and mature elastic fibers, which were shown to be associated with the surface of the convoluted collagen bundles. Thin fibrils were observed in the compression region after ANS treatment. The visceral paratenon had an increased number of elastic fibers located between the collagen bundles and close to the cells. Congo red plus polarization microscopy failed to impart birefringence to the elastic fibers, but they could be identified by their intense staining and isotropic appearance against the bright background of birefringent collagen fibers. SEM demonstrated the three-dimensional aspects of the elastic fibers. They are composed of fibrils of a sinuous nature. The use of ruthenium red in the fixative allowed for the observation of an intimate association of proteoglycan granules with the microfibril bundles. The elastic components identified in the pressure-bearing tendon are assumed to be important for the tissue supramolecular organization, especially in the maintenance of the convoluted state of the collagen fibers in the compression region and their crimp morphology in the tension region. The elastic system must also play an important role in the restoration of the resting shape of the tendon after the deformation achieved during mechanical stimulation.