PubMed Health⌕ Search

Biomedical subjects

G Monga

Publications and source records attributed to G Monga.

At least 55 records · Page 3Linked to original sources
PubMed1992

Intertubular capillary changes in kidney allografts: a morphologic investigation on 61 renal specimens.

A total of 61 kidney allograft specimens (51 biopsies and 10 nephrectomies) from 44 patients were investigated. Transplant glomerulopathy (TGP) was found in 38 specimens. Electron microscopy disclosed peculiar intertubular capillary changes (ITCC) in 47 specimens (all those showing TGP and nine without TGP). They were characterized by splitting and multilayering of the basement membranes. TGP and ITCC were graded and found mild (in 23 and 22 specimens), moderate (in 11 and 16 specimens), and severe (in four and nine specimens). Both worsened with time lapse from transplantation. When both were compared in single specimens, their grading was similar or, with a few exceptions, more severe for ITCC. TGP and ITCC were more frequent in biopsies with morphologic evidence of rejection and less frequent in patients treated with Cyclosporine A. Repeated biopsies and nephrectomies were studied in 10 patients and a somewhat more precocious appearance of ITCC than of TGP was found. Earlier and more severe ITCC were found in two patients who had had two transplants as compared to those with one. Morphologic similarities between TGP and ITCC suggest a common pathogenetic mechanism related to endothelial damage. The association to the histological evidence of rejection as well as the apparently protective activity of Cyclosporine A could support the involvement of an immune-mediated mechanism in agreement with what is reported in literature. The constant association of ITCC and TGP and its possible more precocious appearance enforce the diagnostic value of the former, which allows to infer the presence or the subsequent development of TGP even in biopsies where glomeruli are lacking.

Adult↗
PubMed1991

The association of IgA glomerulonephritis and thin glomerular basement membrane disease in a hematuric patient: light and electron microscopic and immunofluorescence investigation.

A double glomerulopathy (IgA glomerulonephritis [IgAGN] associated with thin glomerular basement membrane disease [TGBMD]) is reported in a 39-year-old woman presenting with macroscopic-microscopic hematuria. Her 3-year-old daughter was also affected by microhematuria of probable glomerular origin. The diagnosis of IgAGN was made by means of immunofluorescence investigation, which showed generalized diffuse mesangial deposits. TGBMD was identified by electron microscopic investigations, which disclosed thinning (up to 160 nm) of basement membrane of several capillary loops and prominence of the lamina densa. Bearing in mind the known frequencies of the two glomerulopathies, their association may not be coincidental, and, therefore, is worthwhile researching in hematuric patients.

Basement Membrane↗
PubMed1991

Renal vascular lesions as a marker of poor prognosis in patients with lupus nephritis. Gruppo Italiano per lo Studio della Nefrite Lupica (GISNEL).

The frequency of renal vascular lesions (RVL) and their relevance in the progression of renal damage were evaluated by the Pathology Group of the "Gruppo Italiano per lo Studio della Nefrite Lupica" (GISNEL). Of 285 patients with lupus nephritis collected from 20 nephrology centers in Italy and classified according to World Health Organization (WHO) criteria, 79 cases (27.7%) with RVL were identified and classified as follows: (1) lupus vasculopathy (n = 27); (2) hemolytic-uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP) malignant hypertension-like lesions (n = 24); (3) vasculitis (n = 8); (4) arterio-arteriosclerosis (n = 20). At the time of renal biopsy, patients with RVL had mean serum creatinine levels significantly higher than patients without RVL (201.8 +/- 195.9 mumol/L [2.2 +/- 2.2 mg/dL] v 108.1 +/- 108.0 mumol/L [1.2 +/- 1.2 mg/dL]; P less than 0.01). Hypertension was more frequent in patients with RVL than in those without (68.4% v 30.5%; P less than 0.01). The probability of kidney survival assessed according to the Kaplan-Meier method at 5 and 10 years was, respectively, 74.3% +/- 5.9% and 58.0% +/- 8.9% in patients with RVL, compared with 89.6% +/- 2.7% and 85.9% +/- 3.7% in patients without RVL. However, the two groups did not differ significantly as regards overall survival, the probability of survival at 5 and 10 years being 86.5% +/- 4.5% and 78.8% +/- 6.6% in patients with RVL and 92.2% +/- 2.2% and 83.3% +/- 4.4% in patients without RVL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Signet-ring cell carcinoid of the gallbladder.

A case of signet-ring cell carcinoid of the gallbladder is reported. The tumour diffusely infiltrated the gallbladder wall and extensively ulcerated the mucosa. Neoplastic nests were composed of numerous signet-ring cells mixed with clear endocrine cells. The latter expressed chromogranin A, gastrin and somatostatin and contained neurosecretory granules. The diagnostic problem of differentiating between signet-ring cell carcinomas and composite adenocarcinoma-carcinoid tumours is discussed.

Adenocarcinoma↗
PubMed1990

Glomerulonephritis with organized deposits: a new clinicopathological entity? Light-, electron-microscopic and immunofluorescence study of 12 cases.

Twelve cases of glomerulonephritis in patients without systemic diseases, displaying organized glomerular deposits, were reported. Microfibrils (11-30 nm diameter) were found in 9 patients and microtubules (20-35 nm diameter) in the other 3. Histochemical stainings for amyloid were always negative. By light microscopy, mesangial proliferative, membranous and membranoproliferative patterns were seen in 5, 3 and 4 patients, respectively. By immunofluorescence, granular deposits, mainly of IgG and C3, were found in all cases, either in the mesangium or in the mesangium and in the capillary walls. A second biopsy was performed in 2 patients. The number of hyaline glomeruli was increased, but the general pattern of glomerular changes remained unchanged. The commonest clinical findings were hypertension, microhematuria and proteinuria, often of nephrotic range. At variance to what is reported in the literature, 2 pediatric cases were found as well, and the overall prognosis (mean follow-up 54.3 months) was mostly favorable. The diagnostic relevance of these findings is pointed out, but further investigations are needed, before suggesting a new clinicopathological entity.

Actin Cytoskeleton↗
PubMed1990

Pattern of double glomerulopathies. A clinicopathologic study in nine nondiabetic patients.

Nine new cases of double glomerulopathies (GP) were found among 1,715 renal biopsies. Immunofluorescence and electron microscopy were needed to achieve a correct diagnosis and the prevailing relevance of these techniques in single cases was stressed. IgA nephropathy was the most commonly found GP, being associated with membranous glomerulonephritis (GN) (2 patients), minimal change disease (3 patients), and focal segmental glomerulosclerosis (1 patient). In addition, single cases of membranous GN plus crescentic GN and acute GN plus cryoglobulinemic GN were recorded. Possible factors involved in the pathogenesis and clinical significance of double glomerulopathies are discussed.

Adult↗
PubMed1990

[Maculo-papular juvenile xanthogranuloma. Considerations on a case].

A case of a 6-month-year old child with a yellow, macular and papular, asymptomatic, eruption involving the extremities, upper part of trunk and especially the head is reported. In the early stage histological and immunohistochemical studies were not contributory. Successively, the diagnosis of juvenile xanthogranuloma was made on the basis of the histological, immunohistochemical and ultrastructural findings. Problems of differential diagnosis are discussed.

Arm↗
PubMed1989

Mesangiolysis and endothelial lesions due to peroxidative damage in rabbits.

There is much evidence that oxygen free radicals (OFR) may be the final mediators of biochemical and molecular damage in many kidney diseases of different etiology (toxic, ischemic and immunologically mediated), involving mainly endothelium, basement membrane and tubular cells, but direct demonstration of a role in inducing mesangiolysis is lacking. An experimental model of renal damage caused by OFR was carried out in 6 rabbits using a mixture of xanthine-oxidase and xanthine, which produces a large amount of the radical superoxide anion. Both enzyme (0.0150 and 0.150 U/ml) and substrate (0.2 and 2 mM) were simultaneously infused in one kidney, while the controlateral kidneys perfused with buffer only were used as controls. Treated kidneys were compared to controls by light and electron microscopy. A further experiment was carried out in 4 other rabbits to evaluate the protection afforded by superoxide dismutase, the specific enzyme-scavenging superoxide anion. Microscopic studies showed dose-related ingravescent damage in the treated kidneys: capillary enlargement, subendothelial swelling, detachment of the endothelium from the basement membrane, mesangiolysis and microaneurysms. Control kidneys appeared to be normal. No significant differences were observed in the kidneys treated with addition of superoxide dismutase. These results are the first direct demonstration of a role of superoxide anion in the induction of mesangiolysis in rabbits. The lack of a protective effect by superoxide dismutase could mean that the superoxide anion triggers a chain of other OFR, further responsible for damage.

Animals↗
PubMed1989

Pattern of double glomerulopathies: a clinicopathologic study of superimposed glomerulonephritis on diabetic glomerulosclerosis.

Among 1715 renal biopsies investigated by means of light microscopy, immunofluorescence, and/or electron microscopy, 20 cases of various glomerulopathies (GP) were found to be superimposed on diabetic glomerulosclerosis (DGS). The most frequently superimposed GPs were acute GN (nine cases) and cryoglobulinemic GN (six cases). Although the former association is known to occur, the latter has not so far been reported. In the other patients DGS was associated with crescentic GN (two cases), membranoproliferative GN, membranous GN, and IgA nephropathy (one case each). Morphologic clues allowing the identification of the superimposed GP and the diagnostic relevance of the available morphologic methods were stressed. In particular, light microscopy was sufficient to identify the superimposed crescentic GN, whereas immunofluorescence and/or electron microscopy were needed in the other cases in order to show the composition and the seat of the deposits, respectively. In addition, electron microscopy was useful in identifying some peculiar features such as humps, mesangial cell interposition, and organized deposits in cryoglobulinemic GN. The actual frequency of superimposed GPs is difficult to assess: either under or overestimation is possible. Pathologists must be aware that this miscalculation is not an episodic event and that the estimation must be carefully sought whenever clinical data are equivocal and not fully fitting with DGS alone. The duration of the diabetes seems to favor the superimposition of GN on DGS. In these patients the prognosis is poor, not only when it could be expected to be, as in the cases with superimposition of crescentic or membranoproliferative GN, but also when DGS is associated with acute GN, whose prognosis is generally favorable.

Adult↗
PubMed1988

Immune-mediated glomerulonephritis after exposure to paraquat.

Exposure to paraquat was followed 1 week later by mild respiratory distress in a previously healthy farmer who developed a mixed nephrotic/nephritic syndrome 3 months later. Percutaneous renal biopsy showed endo-extra-capillary proliferative glomerulonephritis associated with a linear pattern of IgG deposits along the glomerular capillary wall. This is the first case report of an association between exposure to a low dose of paraquat (as suggested by the mildness of the respiratory symptoms) and development of glomerulonephritis, possibly related to the occurrence of anti-glomerular basement membrane antibodies. The possibility is suggested that immune-mediated mechanisms of glomerular damage may be triggered by exposure to low-dose paraquat.

Adolescent↗
PubMed1987

Early sarcolemmal dysfunction in skeletal muscle amyloidosis.

Weakness and stiffness appeared in a 65-year-old man affected by multiple myeloma. Muscle fibre conduction velocity was recorded in situ in the biceps brachii and found to be significantly decreased. Muscle biopsy, performed in the same muscle, showed amyloid deposition and moderate atrophy of muscle fibres, which was not sufficient to explain the reduction in muscle fibre conduction velocity. The results of the study suggest that amyloid interferes with conduction along the sarcolemma and that this plays a pathogenetic role mainly in the early stages of the disease.

Aged↗
PubMed1987

Ultrastructural glomerular findings in cryoglobulinemic glomerulonephritis.

Thirty-three renal biopsies of patients affected by cryoglobulinemic glomerulonephritis (CRYGN) were investigated by electron microscopy, paying particular attention to the nature of cells responsible of glomerular hypercellularity, the presence and site of electron-dense deposits and their ultrastructural characteristics. Personal as well as literature data suggest (a) diffuse glomerular hypercellularity found in most cases of CRYGN is mainly due to polymorphonuclear leukocytes and even more to monocyte exudation; (b) the interposition of the latter cell type in the glomerular capillary wall is the main responsible cause of the frequent occurrence of the membranoproliferative pattern in CRYGN, and (c) peculiar structures found in the electron dense deposits are characteristic of CRYGN and related to cryoglobulin composition. Electron microscopy therefore seems to be a valuable diagnostic procedure for this type of glomerulonephritis.

Cryoglobulinemia↗
PubMed1986

Platelet cationic proteins are present in glomeruli of lupus nephritis patients.

Synthetic polycations have been shown to bind and neutralize glomerular polyanions (GPA), thereby increasing the permeability of the glomerular capillary wall (GCW). In the present study it is demonstrated that human platelet-derived cationic proteins (HuPlt CP), which are able to increase cutaneous vascular permeability, bind in vitro to the GCW following incubation of normal human kidney sections with purified HuPlt CP or with washed human platelets stimulated with thrombin, immune complexes (IC) and platelet-activating factor (PAF), or stimulated with a suspension of washed human platelets and polymorphonuclear leukocytes in the presence of phagocytable substrate. The antiserum used in immunofluorescence test to detect the binding of HuPlt CP was specific for two different molecular types of HuPlt CP, both with an isoelectric point (pI) of 10.5. Glomerular deposits of HuPlt CP were also detectable by immunofluorescence microscopy in renal glomeruli present in tissue obtained by biopsy from patients with systemic lupus erythematosus (SLE), a disease in which platelets have been implicated as mediator of glomerular injury. These data indicate that when activated platelets release HuPlt CP in vivo, these proteins bind to glomerular structures. The binding of HuPlt CP to GCW appears to be ionic in nature since heparin, a polyanion, prevents this binding in vitro. In addition, heparin, as well as a high molarity buffer, removed deposits of HuPlt CP bound in vitro to normal GCW or bound in vivo to glomeruli of patients with SLE. The binding of HuPlt CP to GCW is associated with loss of colloidal iron staining, a qualitative technique that demonstrates primarily epithelial cell surface anionic sialoglycoproteins. In experiments of in vitro binding of purified HuPlt CP to section of normal kidney treatment with heparin completely restores the normal pattern of colloidal iron staining suggesting ionic neutralization of GPA. In contrast, heparin is only partially effective in restoring colloidal iron staining in normal kidney sections treated with platelets directly stimulated with IC or PAF or in kidney sections of patients with SLE. These observations indicate that under these conditions the ionic interaction of HuPlt CP with GCW is only partially responsible for the loss of colloidal iron staining. The results of the present study suggest that biologically active polycationic mediators released from stimulated platelets localize in GCW and participate in the induction of glomerular injury.

Adult↗
PubMed1986

Steroid-sensitive nephrotic syndrome with mesangial IgA deposits: a separate entity? Observation of two cases.

In minimal-change steroid-sensitive nephrotic syndrome with selective proteinuria, mesangial IgA deposition at immunofluorescence is a very rare finding which has been previously considered a pure coincidence. Two patients, aged 6 and 14 years, respectively, with a steroid-sensitive but frequently relapsing nephrotic syndrome and highly selective proteinuria, exhibited minor glomerular alterations at light microscopy and an immunofluorescence deposition of predominant and diffuse mesangial IgA, confirmed by electron microscopy as dense deposits. The observed syndrome, that is surprisingly identical to sporadic literature reports, can be considered a separate entity or subgroup belonging either to IgA nephropathy or to lipoid nephrosis. In the latter case mesangial IgA could be the marker of an easy relapsing course.

Adolescent↗
PubMed1986

Cell interposition in glomerular capillary walls in cryoglobulinemic glomerulonephritis (CRYGN). Ultrastructural investigation of 23 cases.

The present report describes ultrastructural findings on twenty-three cases of CRYGN showing membranoproliferative pattern under light microscopy. Attention was paid to the presence of double contoured peripheral basement membranes and to the characteristics of the interposed cells. The latter, according to the well known characteristics of membranoproliferative GN, are thought to be mesangial in nature. In fact, mesangial cells were found in 8 cases only, always associated with monocytes. Only monocytes were recorded in 12 cases, whereas in other 3 cases double contours were not connected to cell interposition. Despite similarities under light microscopy, CRYGN is therefore rather different from idiopathic membranoproliferative GN because of the prevalence of exudative changes, mainly due to monocyte infiltration, over proliferative lesions.

Cryoglobulinemia↗
PubMed1985

Benign clear cell (sugar) tumor of the lung. A light microscopic, histochemical, and ultrastructural study with a review of the literature.

A case of a benign clear cell "sugar" tumor of the lung is reported. Light microscopy showed a uniform proliferation of clear cells filled with abundant glycogen. At the ultrastructural level, tumor cells were rich in free monogranular and rosette-forming glycogen, but no membrane-bound glycogen was demonstrated. Some cells showed plasma membrane interdigitations, microvilli, and macula occludens-type junctions. Many polymorphic secretory and sporadic haloed neurosecretory-like granules were observed, but argyrophil stains as well as a large set of immunohistochemical reactions specific for APUD derivation had negative results. A literature review of this puzzling entity with particular emphasis on the histogenetic hypotheses is presented, and a derivation from epithelial nonciliated bronchiolar (Clara) cells or epithelial serous cells is suggested.

Adult↗