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Biomedical subjects

G Monga

Publications and source records attributed to G Monga.

At least 73 records · Page 4Linked to original sources
PubMed1985

Glomerular monocyte infiltration in human nephropathies: prevalence and correlation with clinical and morphological variables.

Glomerular monocyte infiltration was evaluated by histochemical means (nonspecific esterase) and/or electron microscopy in 305 renal biopsies belonging to a wide variety of human renal diseases. Significant monocyte infiltration was never observed in a first group of nepropathies (minimal change disease, nephrotic syndrome with IgM deposits, focal segmental glomerulosclerosis, membranous GN, Berger's GN, healed GN, dense deposit disease, chronic non specific GN, benign familial haematuria, Alport's disease, renal amyloidosis, arteriosclerotic kidney, light chain GN). Conversely, it was present at varying frequency in a second group of nephropathies including: acute GN (58.3%), persistent GN (10%), membranoproliferative GN (25.2%), eryoglobulinaemic GN (82.6%), lupus GN (36%), extracapillary proliferative GN (50%) and Schoenlein-Henoch GN (40%). The results indicate: 1) there is an evident association between monocyte infiltration and the subendothelial site of deposits; 2) the presence of monocytes is not affected by the size and extension of subendothelial deposits; 3) monocytes were more frequently observed when IgG, IgM and fibrinogen were present in the subendothelial deposits, Conversely, complement fractions do not seem to affect monocytic activity; 4) polymorphonuclear leukocyte exudation is less frequently found and mostly associated with monocyte infiltration; 5) in some GNs (persistent GN, cryoglobulinaemic GN and membranoproliferative GN), proteinuria was significantly higher in patients with than in those without monocyte infiltration, giving support to the hypothesis that in human beings as in experimental animals monocytes play a role in the pathogenesis of proteinuria.

Biopsy↗
PubMed1985

Monocyte escape through a glomerular capillary basement membrane gap. An ultrastructural observation in a case of acute glomerulonephritis.

A focal discontinuity of glomerular basement membrane (GBM) with extravasation of a monocyte is described in a case of acute postinfectious glomerulonephritis in a 2-year-old girl. It is proposed that also monocytes could play a role in causing disruption of glomerular capillary wall. Moreover, this finding gives morphologic support to the hypothesis that monocyte-forming crescents reach the urinary space through GBM gaps.

Basement Membrane↗
PubMed1985

Morphological parameters in lupus nephritis: their relevance for classification and relationship with clinical and histological findings and outcome.

One hundred and sixty-seven renal biopsies from 147 patients with lupus nephritis were studied retrospectively to assess the contribution to morphological classification by features assessed with immunofluorescence and electron microscopy, together with pathological indices obtained by scoring specific histologic changes. The prognostic relevance of the histologic scoring was also evaluated. The biopsies were assigned to the following classes: I, absence of glomerular lesions; II, mesangial proliferation; III, focal segmental proliferation; IVa, diffuse (more than 50 per cent of the glomeruli) but segmentally distributed proliferation; IVb, diffuse and generalised proliferation; IVc, extracapillary proliferation; Va, pure membranous changes; Vb, membranous changes with slight mesangial proliferation; VI, association of class V and class III or IV. The incidence and degree of some glomerular and non-glomerular 'active' and 'sclerotic' changes as assessed by light microscopy were evaluated in the different classes. Both the activity and sclerosis indices obtained by scoring these lesions were found to be significantly higher in classes with glomerular proliferative changes. Eighteen patients had a second biopsy and two of these had a third; more severe changes were observed in nine and improvement in four. In 146 biopsies light microscopy findings were compared with immunofluorescence patterns (negative, mesangial, mesangial and peripheral, peripheral, membranous). The mesangial pattern was mainly present in class II with a few examples in classes I and III; in the last two the mesangial-peripheral pattern was most common; the peripheral pattern was by far the most common in class IV (a, b and c) and frequent in class VI; a membranous pattern was the rule in class V and occasionally found in class VI. Immunoglobulins (Igs) and complement (C) fractions were simultaneously present in most cases, IgG, C3 and C1q being the commonest in all classes. Except for IgM and fibrinogen, the differences in distribution of Igs and C fractions among the various classes were statistically significant. The deposits most commonly found by electron microscopy in all biopsies were mesangial; subendothelial deposits were mainly found in classes with active glomerular changes, frequently associated with deposits at the other sites in the most severe cases. A highly significant correlation was found between the activity index and the sclerosis index and severity of the clinical picture at biopsy. An unfavourable progress was confined mainly to classes with extensive intracapillary proliferation and correlated significantly with the highest activity and sclerosis indices.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

Essential mixed cryoglobulinemic glomerulonephritis associated with diabetic glomerulosclerosis. Light, immunofluorescence, and ultrastructural study of two cases.

The association of cryoglobulinemic glomerulonephritis with diabetic glomerulosclerosis is reported in two patients. Renal pathology was investigated by light and electron microscopy and by immunofluorescence on biopsy material from both patients and on autopsy material (obtained a few hours after death) from one patient. Glomerular involvement due to cryoglobulins preceded the development of diabetic glomerulosclerosis in one patient. This contrasts with what has been reported in the literature, where various types of glomerular lesions are reported to be superimposed on overt and often long-lasting diabetic glomerulopathy. Though the association may be coincidental, the immune complexes (cryoglobulins) may have accelerated the formation of the nodular hyaline diabetic lesions in the mesangium through a mesangiolytic process.

Cryoglobulinemia↗
PubMed1984

Detection of monocytes and evaluation of their role in human glomerular pathology: the contribution of electron microscopy.

The potentialities of electron microscopy in detecting monocytes in human glomeruli are discussed and its reliability is compared with that of other techniques (such as enzyme histochemistry and immunohistochemistry) having the same purposes. The major advantages of electron microscopy are: the same material can be used for both monocyte detection and conventional diagnostic purposes; its high resolution power allows for information on the site of monocyte infiltration and clarification of some functions of the latter (such as the phagocytic activity on immune complexes or their participation to the basement membrane damage). Nevertheless, the suggested technique also has some disadvantages, in particular it permits to investigate only a small number of glomeruli and it creates difficulties in the identification of nonstimulated monocytes.

Glomerulonephritis↗
PubMed1982

Severe glomerular mesangiolysis in a patient with rectal adenocarcinoma treated with cytotoxic drugs.

A 72 year old man with rectal adenocarcinoma developed chronic renal failure when treated by surgery and subsequent chemotherapy (5-fluorouracil, Mitomycin C and Cytosine arabinoside) and immunotherapy. Light microscopy provided evidence of severe glomerular changes with extensive mesangiolysis and vascular damage. Electron microscopy confirmed the mesangiolysis and showed nuclear changes in mesangial cells with nuclear pockets, chromatin loss and margination. There was further indirect evidence of endothelial cell damage. It is suggested that the glomerular changes should be attributed to a direct cytotoxic effect on the mesangial cells.

Adenocarcinoma↗
PubMed1982

The use of Mallory's phosphotungstic acid-hematoxilin (PTAH) stain in renal pathology.

High quality histology is needed in renal biopsy examination, especially when material for immunofluorescence and/or electron microscopy is not available. For these purposes Mallory PTAH stain was tried on 34 renal biopsies and the results were compared with the immunofluorescent and ultrastructural findings (used as a control of the reliability of the method). PTAH, besides showing extracellular structures, cytological details and rather subtle abnormalities, was able to detect the presence and the site of deposits. PTAH stains the material which appears as electron dense deposits in electron microscopy and as granular deposits in immunofluorescence, whereas it fails to stain linear deposits in immunofluorescence (which are not electron dense). Moreover, a good correspondence between PTAH and electron microscopic data was detected as far as the location of deposits is concerned.

Amyloidosis↗
PubMed1981

The significance of minimal alterations in muscle biopsy of Duchenne carriers.

In order to define the significance of minimal histological and ultrastructural abnormalities in Duchenne carriers, 18 normal healthy volunteers were examined by muscle biopsy. Light microscopy evidenced occasional internal nuclei and less frequent small round and angular fibres. Variability of fibre size, increase in connective tissue, necroses and basophilia found in carriers were not present in controls. Histograms constructed on ATPase stain sections demonstrated variability in distribution of fibre types both in normals and in carriers. Fibre size was more variable in carriers, where a significant decrease of the size of type II B fibres was observed. Electron microscopy evidenced knots in overcontraction, myofibrillary widening, subsarcolemmal accumulation of mitochondria and Z band streaming, which have been reported also in carriers. The results are discussed and compared with the data of the literature.

Adult↗
PubMed1981

Monocyte infiltration and glomerular hypercellularity in human acute and persistent glomerulonephritis. Light and electron microscopic, immunofluorescence, and histochemical investigation on twenty-eight cases.

Glomerular monocyte infiltration was searched for using staining for nonspecific esterase and/or electron microscopy in 28 patients with acute glomerulonephritis submitted to biopsy at different intervals from the beginning of the disease. Significant monocyte infiltration was detected in 12 cases displaying prominent intracapillary hypercellularity and granulocyte exudation. All cases but one were submitted to biopsy in the first 6 weeks of the disease. Negative cases, submitted to biopsy in the same period or in the later phases of the disease, displayed more or less evident mesangial hypercellularity as the prevailing feature. Most positive cases showed glomerular deposits of IgG. Phagocytosis of IgG by mononuclear cells was investigated in all cases positive for monocytes and in 10 negative ones, using an immunofluorescence technique on paraffin-embedded material. Only in the former group were a few or scanty IgG-phagocytosing monocytes detected in six cases. Our results only partially confirm the role of monocytes in causing glomerular hypercellularity in human acute glomerulonephritis. In fact, the relevance of this phenomenon appears much less important than in several well-known experimental models and in some cases of human chronic glomerulonephritis. Moreover, macrophage infiltration is present in cases with greater immunologic involvement and tends to decline with time. Therefore, it seems that, in human acute glomerulonephritis, glomerular hypercellularity results mainly from intrinsic cell proliferation.

Acute Disease↗
PubMed1980

Glomerulonephritis with dense deposits: a variant of membranoproliferative glomerulonephritis or a separate morphological entity? Light, electron microscopic and immunohistochemical study of eleven cases.

Eleven cases of glomerulonephritis with dense deposits were selected on the basis of electron microscopic examination performed either on material treated according to conventional techniques (9 cases) or on previously paraffin-embedded material (2 cases). While uniform immunohistochemical patterns were observed, different features were shown by light microscopy: in only 3 cases were membranoproliferative or lobular patterns present, while in the others a varying degree of mesangial cell proliferation (moderate, mild or even very scanty with focal and segmental distribution) was detected. The generally accepted statement that glomerulonephritis with dense deposits represents a subgroup of membranoproliferative glomerulonephritis therefore seems questionable. In addition to several clinical and serological data, these morphological features give further support to the hypothesis that glomerulonephritis with dense deposits in all respects a peculiar and distinct form of glomerulonephritis.

Adolescent↗
PubMed1979

Colorectal polyposis with mixed juvenile and adenomatous patterns.

An unusual form of colorectal polyposis is described displaying juvenile, adenomatous and mixed patterns in a 17-year-old girl. Although juvenile polyposis is generally considered to be non-neoplastic in nature, in both the present and in other case reports histological findings support a neoplastic nature. Since an increase in the incidence of large bowel carcinomas has been found in subjects with a previous diagnosis of juvenile polyposis, these patients should be considered to be at risk, and submitted to follow up.

Adenoma↗
PubMed1979

Medullary carcinoma of the thyroid with atypical patterns.

A case of a highly invasive thyroid carcinoma, which occurred in a 68-year-old woman, was studied by light and electron microscopy, and histochemical and biochemical analysis. Light microscopical, histochemical, and biochemical features were consistent with a diagnosis of a calcitonin-producing, amyloid-rich medullary carcinoma; electron microscopical patterns, mainly the presence of lumina, microvilli, and extensively dilated cytoplasmic E.R., were reminiscent of the ultrastructural features of the follicular carcinoma. Electron-dense bodies interpreted as "secretory granules" were very scarce. This case appears very similar to the case recently presented by Valenta et al. and interpreted as a microfollicular carcinoma. The atypical features of our case of MCT seem to indicate that this tumor should be included in a group of atypical MCT; these should be kept separate from the typical (differentiated) ones on morphological, functional, and prognostic grounds.

Aged↗
PubMed1979

Mitochondrial abnormalities of late motor neuron degeneration following poliomyelitis and other neurogenic muscular atrophies.

A case of late motor neuron degeneration following poliomyelitis with abnormal mitochondria in muscle fibers is presented with two additional cases of systemic neurogenic muscular atrophy (Charcot-Marie-Tooth disease). Muscle biopsy revealed a neurogenic pattern of variable severity in all cases. Subsarcolemmal zones of hyperactivity and hyperpositive intermyofibrillar collections of granular material present in a variable proportion of type I fibers were demonstrated by oxidative enzymes. Ultrastructurally they corresponded to abnormal mitochondria, with paracrystalline inclusions in one case. The finding is discussed in the light of the previous literature on mitochondrial myopathies. Mitochondrial alterations are not specific and their significance in neurogenic conditions is debated.

Adolescent↗
PubMed1979

The presence and possible role of monocyte infiltration in human chronic proliferative glomerulonephritides. Light microscopic, immunofluorescence, and histochemical correlations.

Twenty-seven cases of chronic glomerulonephritis with proliferative pattern (11 cases of primary mixed IgG-IgM cryoglobulinemia, 8 cases of SLE, and 8 cases of primary membranoproliferative glomerulonephritis) were studied with particular attention to the glomerular monocyte infiltration. The latter, detected by means of nonspecific esterase technique, was compared with the presence of hyaline thrombi and intraluminal immunoglobulin lumps. Monocyte infiltration was heavy and almost constant in cryoglobulinemia, less important in SLE, and practically absent in membranoproliferative glomerulonephritis. By means of immunofluorescence technique on paraffin embedded material, monocytes are shown to contain IgG and IgM, suggesting a phagocytic activity on some types of immune complexes. Since monocytes are migrant cells, and therefore easily removable from the glomeruli by the bloodstream, it seems that they could be responsible for regression of glomerular hypercellularity as reported in some patients with cryoglobulinemia showing clinical improvement.

Chronic Disease↗
PubMed1978

Central core disease: histochemical and ultrastructural study of muscle biopsies of father and daughter.

Two cases of central core disease, father and daughter, of a family with dominant autosomal inheritance, are presented, one with bilateral congenital dislocation of the hip. Muscle biopsy was performed in both cases. Oxidative enzymes evidenced only type I fibers, most of them presenting a central core and not uncommonly more than one. On electron microscopy the cores generally appeared well demarcated from the surrounding fibrils and were characterized by lack of mitochondria and abnormalities of the Z line. Transitional aspects from normal fibers to completely unstructured cores were observed, as well as from well structured and unstructured cores. These findings are discussed in the light of the previous literature and particular attention is paid to the problem of differentiation between central core and multicore disease. The pathogenesis of the muscular alteration is also discussed in relation with the possibility of their neurogenic origin. Eventually, the histochemical and ultrastructural similarities between central cores and target fibers are focused.

Biopsy↗
PubMed1978

Multiple endocrine cell types in thyroid medullary carcinoma. Evidence for calcitonin, somatostatin, ACTH, 5HT and small granule cells.

10 cases of thyroid medullary carcinoma (TMC) have been studied ultrastructurally and histochemically. Well differentiated calcitonin-producing C cells were present in all tumours, being prevalent in 9 cases. 5-Hydroxytryptamine (5HT) storing cells were found in two cases, somatostatin immunoreactive cells in at least 5 cases and ACTH-immunoreactive cells in 4 cases. Ultrastructurally, at least 3 types of apparently non-C cells were observed. Type 1 cells with large, poorly osmiophilic granules resembling those of gastroenteropancreatic D cells, were present in 6 cases; they appeared to correlate well with somatostatin immunoreactive cells. Type 2 cells with large osmiophilic granules were found in 5 cases; they resembled ACTH-MSH cells of the human pituitary and may correspond to the ACTH-immunoreactive cells of light microscopy. Type 3 cells with small granules and an unknown function were found in 6 cases, always in scarce number. It is concluded that TMC, although mainly made up of C cells, usually contains large proportions of other endocrine cell types.

Adrenocorticotropic Hormone↗
PubMed1978

Histochemical and ultrastructural findings in a case of centronuclear myopathy.

A case of centronuclear myopathy is presented. The presence of central nuclei in almost all fibres, the existence of type I fibres only, the histochemical pattern of a negative central zone with a perinuclear halo and a hyperactive rim with oxidative enzymes and the ultrastructural data are discussed in the light of the previous literature. The possible relationships with other myopathies are taken into consideration as well as the fact that central nuclei may be a non-specific change in several conditions. Consequently centronuclear myopathy could turn out to be a syndrome from which different entities can be isolated.

Adenosine Triphosphatases↗