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Biomedical subjects

A O Muda

Publications and source records attributed to A O Muda.

At least 19 recordsLinked to original sources
PubMed2001

Acquired glomerulocystic kidney disease following hemolytic uremic syndrome.

Glomerulocystic kidney disease (GCKD) is a rare congenital condition that is usually reported in infants and young children. Only five cases of acquired GCKD after an acquired renal disease have been reported. Among these, two patients have developed cystic glomerular lesions following hemolytic uremic syndrome (HUS). We report a third case in a 2-year-old patient with this association. Common features between these three cases include atypical HUS, development of GCKD after prolonged peritoneal dialysis treatment, severe hypertension, and normal-sized kidneys without development of macroscopic cysts. Pathology findings in our patient include heavy expression of epidermal growth factor receptor in proximal tubules and evidence of obstruction of the glomerular outflow. We speculate that cystic dilatation of the Bowman's capsule may be secondary to ischemic lesions leading to proximal tubular obstruction.

Child, Preschool↗
PubMed2001

Distribution of alpha-chains of type IV collagen in glomerular basement membranes with ultrastructural alterations suggestive of Alport syndrome.

BACKGROUND: In Alport syndrome (AS) impaired production and/or assembly of col IV alpha-chain isoforms results in abnormal structure of glomerular basement membrane (GBM), haematuria and, frequently, progressive renal disease. We investigated the relationship between col IV alpha-chains expression and morphology of GBM, as a possible key to the better understanding of the pathogenesis of renal disease in AS. METHODS: GBM distribution of col IV alpha1-, alpha3-, and alpha5-chain was investigated by immunohistochemistry in 32 patients (21 males and 11 females, mean age at biopsy of 11.5 years) with ultrastructural findings suggestive of AS. Ten patients had a proven COL4A5 mutation. Based on the severity of ultrastructural findings, the biopsies were grouped in three (I-III) electron microscopy (EM) classes. Significant EM changes of GBM (thinning, thickening, splitting, basket weaving of the lamina densa) were singularly evaluated using a semiquantitative scale (0-3). RESULTS: Col IV alpha1-chain was demonstrated in GBM of all patients. Three patterns of staining for col IValpha3- and alpha5-chains were observed: positive, negative, and alpha3(IV)-positive/alpha5(IV)-negative. By chi(2)-test, EM class III lesions and complete loss of alpha3(IV)- and alpha5(IV)-antigen were significantly more frequent (P<0.05 and P<0.01) in male patients, but no significant relation was observed between EM classes and immunohistochemical patterns. GBM alterations did not correlate with staining for alpha5(IV)-chain. Intensity of alpha3(IV)-chain staining, however, had a negative correlation (P<0.05) with the severity of GBM basket weaving. CONCLUSIONS: Our results suggest that the alpha3(IV)-chain-containing col IV-network plays a fundamental role in structural and, possibly, functional organization of GBM. Absence of alpha3(IV)-chain in GBM could indicate a more severe renal disease in AS.

Adolescent↗
PubMed2000

Cephotaxime-associated allergic interstitial nephritis and MPO-ANCA positive vasculitis.

We report a case of reversible acute renal failure after cefotaxime treatment in a patient affected by non-Hodgkin lymphoma. Renal biopsy showed necrotizing vasculitis associated with eosinophil-rich interstitial inflammatory infiltrates and patchy infiltrates of CD20+ lymphoid cells. High serum p-ANCA titers were also detected. Drug withdrawal was closely related with recovery of renal function and disappearance of ANCA. Acute renal failure therefore represented a consequence of ANCA-mediated renal vasculitis and acute interstitial nephritis related to cefotaxime treatment.

Aged↗
PubMed1999

Spatial arrangement of subepithelial deposits in lupus and nonlupus membranous nephropathy.

Subepithelial deposits are a common feature of idiopathic membranous glomerulonephritis (MGN) and lupus membranous glomerulopathy (LMGN). We investigated the spatial arrangement of immunoglobulin G (IgG) and C3c fraction of complement (C3c) in the immune deposits of MGN and LMGN with confocal laser scanning microscopy to correlate specific patterns of IgG-C3 interactions with different diseases. Ten patients with MGN and 8 patients with LMGN (World Health Organization class VB) were selected. A determination of the spatial arrangement of the two fluorochromes and the glomerular area occupied by each fluorochrome was performed for each case. Our results showed MGN specimens have an orderly distribution of IgG and C3c, with each deposit showing an outer ring of sole IgG. IgG was always more abundant than C3c (1,619 +/- 271 v 790 +/- 105 micrometer(2), P = 0.002). In LMGN, IgG and C3c were haphazardly arranged, with deposits made of C3c only and an outer ring of IgG only rarely present. Also, the relative amounts of the two antigens were variable, and two groups could be identified (group 1: IgG, 5,515 +/- 1,179 micrometer(2) v C3c, 4,810 +/- 1,174 micrometer(2); P = 0.02; group 2: IgG, 3,358 +/- 658 micrometer(2) v C3c, 4,047 +/- 740 micrometer(2); P = 0.03). Our data show that diffuse IgG capping of the subepithelial immune deposits is diagnostic of MGN. The absence of an orderly three-dimensional arrangement in LMGN deposits (ie, outer ring of IgG) is likely to render active complement components more readily available to inflammatory activities.

Adult↗
PubMed1999

Immunoglobulin A nephropathy complicating pulmonary tuberculosis.

A 31-year-old man who presented with smear- and culture-negative pulmonary tuberculosis had associated macroscopic hematuria, elevation of serum creatinine and immunoglobulin A (IgA) levels, overt proteinuria, and peripheral edema. Renal biopsy revealed focal mesangial proliferation with IgA deposits, and a diagnosis of IgA nephropathy was made. The patient received treatment with isoniazide and rifampin. After 4 months, pulmonary lesions were almost completely healed, and a significant improvement of creatinine clearance with normalization of serum creatinine and IgA levels and disappearance of proteinuria were observed. Treatment with isoniazide and rifampin was discontinued after 6 months, without reappearance of either pulmonary or renal symptoms. Two years after the diagnosis of IgA nephropathy, the patient is in good general condition. Serum creatinine and IgA levels are normal, proteinuria is absent, and there is neither macrohematuria nor microhematuria. These findings suggest that IgA nephropathy may be a consequence of tuberculosis, possibly due to an abnormal IgA-mediated immune response against Mycobacterium tuberculosis with formation of nephrotoxic immune complexes.

Adult↗
PubMed1999

Copper treatment alters the permeability of tight junctions in cultured human intestinal Caco-2 cells.

The effects of copper on tight-junction permeability were investigated in human intestinal Caco-2 cells, monitoring transepithelial electrical resistance and transepithelial passage of mannitol. Apical treatment of Caco-2 cells with 10-100 microM CuCl(2) (up to 3 h) produced a time- and concentration-dependent increase in tight-junction permeability, reversible after 24 h in complete medium in the absence of added copper. These effects were not observed in cells treated with copper complexed to L-histidine [Cu(His)(2)]. The copper-induced increase in tight-junction permeability was affected by the pH of the apical medium, as was the apical uptake of (64)CuCl(2), both exhibiting a maximum at pH 6.0. Treatment with CuCl(2) produced a concentration-dependent reduction in the staining of F actin but not of the junctional proteins zonula occludens-1, occludin, and E-cadherin and produced ultrastructural alterations to microvilli and tight junctions that were not observed after treatment with up to 200 microM Cu(His)(2) for 3 h. Overall, these data point to an intracellular effect of copper on tight junctions, mediated by perturbations of the F actin cytoskeleton.

Actins↗
PubMed1998

Ultrastructural and immunohistochemical findings in Alport's syndrome: a study of 108 patients from 97 Italian families with particular emphasis on COL4A5 gene mutation correlations.

A total of 108 patients affected by Alport's syndrome, taken from 97 families, were enrolled in a genetic and ultrastructural study. Sixty-four families (75 patients) were X-linked, seven autosomal recessive, two autosomal dominant, five uninterpretable, and 19 sporadic. The ultrastructural features were consistent with Alport's syndrome in 66, doubtful in 20, and not significant for Alport's syndrome in 22 patients in the X-linked, sporadic, and genetically uninterpretable groups (without significant differences), as well as in the autosomal group. Mutations of the COL4A5 gene were present in 36 patients in the first three groups, without significant differences. More severe mutations were more frequently present in patients with an ultrastructural pattern consistent with Alport's syndrome. Nevertheless, there seems to be no strict correlation between mutation and ultrastructure, because a major rearrangement was found in a patient with no significant lesions, and different morphologic patterns were detected in patients Belonging to the same family. Immunohistochemical investigation into 24 patients for alpha (IV) chains showed that both alpha 3(IV) and alpha 5(IV) were lacking in the glomerular basement membrane of 13 patients (five with mutations) and were expressed in another six (three with mutations and one in the autosomal group). On the contrary, in this study the retained expression of alpha 3(IV) chain was found, despite the lack of alpha 5(IV) in the glomerular basement membrane of five patients (two with mutation). These different patterns could be related to both the type and severity of the COL4A5 mutations. All of the ultrastructural patterns were identified in all three immunohistochemical groups. Ultrastructural features and alpha 5(IV) chain production, even if an expression of a genetic mutation, do not strictly correlate. The combined use of analysis of collagen expression and electron microscopy made it possible to diagnose Alport's syndrome in 92% of the cohort, and therefore this approach is advisable. A multidisciplinary approach is recommended in the study of Alport's syndrome in an attempt to achieve a better diagnostic definition of and insight into the pathogenetic mechanisms.

Adolescent↗
PubMed1997

Ultrastructural immunocytochemistry of collagenous and non-collagenous proteins in fast-frozen, freeze-substituted, and low-temperature-embedded renal tissue in Alport syndrome.

This paper describes the ultrastructural immunolocalization of the alpha 2 chain of collagen IV, laminin, and the amino terminal propeptide of collagen I (N-Pro I) in glomeruli of rapidly frozen, freeze-substituted, and low-temperature-embedded renal biopsy specimens from two cases of Alport disease and from normal kidneys. The alpha 2 chain of collagen IV is present in the whole thickness of the basement membrane in glomeruli of Alport patients, while it is limited to the subendothelial portion of the basement membrane of normal glomeruli. Laminin has the same distribution in both normal and Alport glomeruli, but is apparently more concentrated along the basement membrane of normal glomeruli. N-Pro I is localized in mesangial areas and in the basement membrane in Alport cases, while it is not detected in normal glomeruli. These data suggest complex rearrangements of major constituents of the glomerular basement membrane network and demonstrate early deposition of fibrillary collagen proteins in the matrix before the appearance of banded collagen fibres. This finding could be an indicator of early evolution towards glomerulosclerosis.

Basement Membrane↗
PubMed1997

Systemic lupus erythematosus with membranous glomerulonephritis and uterine vasculitis.

We report a case of lupus vasculitis with uterine localization and concurrent membranous nephropathy. Immunofluorescence study suggested the occurrence of an immune complex nephropathy and a pauci-immune pathogenesis of vasculitis. Our case points out the event of tissue damage in two organs mediated by different pathogenetic mechanisms. In addition, uterine vasculitis without pregnancy may be observed in patients with systemic lupus erythematosus nephritis.

Cervix Uteri↗
PubMed1997

Indeterminate cell histiocytosis: a rare histiocytic disorder.

A 64-year-old woman, otherwise healthy, presented with multiple reddish-brown, slightly yellowish papules on the face and neck, which had developed 3 years earlier. The lesions were painless and nonpruritic and varied in diameter from 1 to 5 mm. Histological and immunohistochemical examination of cutaneous biopsies revealed a diffuse dermal infiltrate composed mainly of histiocytes which expressed both Langerhans cell as well as monocytic/macrophages cell marker characteristics. Electron microscopic studies revealed no Birbeck granules within the cytoplasm of the neoplastic cells, leading to a diagnosis of indeterminate cell histiocytosis. Indeterminate cell histiocytosis is a very rare disease characterized by the proliferation of indeterminate histiocytes which morphologically and immunophenotypically resemble Langerhans cells but lack Birbeck granules.

Female↗
PubMed1996

The Dri 42 gene, whose expression is up-regulated during epithelial differentiation, encodes a novel endoplasmic reticulum resident transmembrane protein.

A search for novel genes that are up-regulated during development and differentiation of the epithelial cells of the intestinal mucosa led us to the isolation of the Dri 42 cDNA clone (Dri, differentially expressed in rat intestine). The nucleotide sequence of the full-length cDNA has shown that it encodes a 35.5-kDa protein with one consensus sequence for N-linked glycosylation and alternating hydrophilic and hydrophobic domains. To determine the intracellular localization of Dri 42 we have raised polyclonal antibodies in hens against a bacterially produced Dri 42-glutathione S-transferase fusion protein. Immunofluorescence detection with these antibodies has shown specific staining of the endoplasmic reticulum (ER) in the relatively undifferentiated fetal rat intestinal cell line FRIC B and in sections of rat small intestine. ER membrane localization of Dri 42 was confirmed by laser confocal microscopy of polarized Madin-Darby canine kidney cells overexpressing a Dri 42-chloramphenicol acetyltransferase (CAT) fusion protein by transfection. Pulse labeling experiments on transiently transfected cells demonstrated that the protein does not acquire Golgi modifications up to 4 h after synthesis, thus indicating that Dri 42 is an ER resident protein. The transmembrane disposition of Dri 42 was studied using in vitro insertion of Dri 42-CAT fusion proteins into microsomal membranes. The fusion proteins consisted of several different lengths of truncated Dri 42 and a reporter protein, CAT, that was linked in-frame after each hydrophobic segment. We found that hydrophobic segments H1, H3, and H5 had a signal/anchor function, and that membrane insertion of Dri 42 was achieved co-translationally by the action of a series of alternating insertion signals and halt transfer signals, resulting in the exposure of both termini of the protein to the cytosolic side. The functional implications of the structure and localization of Dri 42, whose primary sequence does not share significant homology to any previously described protein, are discussed.

Amino Acid Sequence↗
PubMed1996

Three-dimensional distribution of basement membrane components in dystrophic recessive epidermolysis bullosa.

Absent or defective collagen VII at the dermo-epidermal junction is the hallmark of dystrophic recessive epidermolysis bullosa. Little is known of the alterations of other collagenous and non-collagenous components of the basement membrane; it is likely that their assembly may be disturbed by the lack of collagen VII molecules. The spatial relationship of collagen IV and laminin has been studied, both in bullous and in non-bullous areas. Skin biopsies from five patients affected by severe dystrophic recessive epidermolysis bullosa were rapidly frozen and freeze-dried. Collagen IV and laminin were labelled with specific monoclonal antibodies and FITC- or TRITC-conjugated secondary antibodies. Sections were observed with conventional light/fluorescence microscopy and with confocal laser scanning microscopy. Collagen IV and laminin were not co-localized: the former displayed a split image, being present at the floor and the roof of the blister, while the latter was confined to the roof. Confocal microscopy also allowed three-dimensional (3D) reconstruction of the dermo-epidermal junction from a series of optical sections, with viewing of the reconstructed specimen from a sequence of angles. By this procedure, laminin exhibits an irregular, coarsely granular distribution, both in affected and in apparently non-affected areas, while collagen IV appears as a homogeneous sheet. These results show that freeze-drying is the technique of choice for high-resolution immunofluorescence of skin samples and suggest that in dystrophic recessive epidermolysis bullosa, a complex disruption of the extracellular matrix assembly exists even before blister formation, probably due to the lack of collagen VII.

Basement Membrane↗
PubMed1996

Adult solitary cutaneous myofibroma: a case report.

The histologic and immunohistochemical features of a case of adult solitary cutaneous myofibroma are reported. The lesion consisted of interlacing bundles of spindle cells arranged around small vessels with hemangiopericytomatous appearance. Neoplastic cells were positive for vimentin and actin. Desmin, cytokeratins and Factor XIIIa were negative. Scattered Langerhans cells positive for S-100 protein and CD1a antigen, usually not reported within this type of neoplasm, were also present.

Adult↗
PubMed1995

Spatial arrangement of IgA and C3 as a prognostic indicator of IgA nephropathy.

The histological picture of primary glomerulonephritis with glomerular IgA deposition (IgA nephropathy and Henoch-Schönlein disease) can vary from minimal mesangial involvement to severe endocapillary and/or extracapillary proliferation. Local activation of the complement cascade by glomerular IgA deposits and release of anaphylactoid factor are considered to be major triggers of inflammation, but clear-cut correlations between the severity of the histological findings and the intensity of glomerular deposition of immunoglobulin and complement fractions are still lacking. The purpose of this study was to investigate the spatial distribution of IgA and complement in mesangial deposits with confocal laser scanning microscopy (CLSM) and to correlate specific patterns of IgA-complement interaction with glomerular damage. Two groups of patients have been studied, one with mild to moderate diffuse mesangial proliferation and the other with diffuse proliferative endocapillary and/or extracapillary patterns. In milder forms of the disease, the majority of the immune deposits are composed of both IgA and C3, coated by an outer layer of IgA alone. Large C3 deposits, or deposits composed of IgA and C3 without an outer coat of IgA, were associated with more severe histological lesions. The results suggest that free access of active complement components to cell and/or mesangial matrix receptors could trigger a cytolytic reaction and that immunoglobulins seem to act as a protective layer on C3 components.

Adolescent↗
PubMed1995

Ultrastructural investigation of circulating villous lymphoid cells: a tool in the differential diagnosis of splenic lymphoma with villous lymphocytes.

Ultrastructural examination of circulating lymphoid cells was performed in three cases of splenic lymphoma with circulating lymphocytes (SLVL) in order to define morphological features helpful to distinguish this lymphoma from hairy cell leukemia (HCL). The samples for ultrastructural investigation were obtained by Ficoll sedimentation from peripheral blood and routinely processed for electron microscopy. The ultrastructural features examined were: morphology of villi, morphology of nuclei, presence of nucleoli, distribution of heterochromatin, type of cytoplasmic organelles, presence of specific intracytoplasmic structures such as the ribosome-lamella complex, lysosome-like bodies and perinuclear microfibrils. Our results and a careful review of the literature seemed to confirm that SLVL has electron microscopic features typical enough to be relevant in the differential diagnosis with HCL.

Adult↗