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Biomedical subjects

G Monga

Publications and source records attributed to G Monga.

At least 37 records · Page 2Linked to original sources
PubMed1997

Renal changes in patients with acquired immunodeficiency syndrome: a post-mortem study on an unselected population in northwestern Italy.

The renal pathologic features of 120 consecutively autopsied patients affected by acquired immunodeficiency syndrome was investigated by light microscopic analysis. Variously associated renal changes were found in 82 patients (68.3%). Glomerular changes were present in 25. The following diagnoses were made: mesangial glomerulonephritis (16 patients), defined by the presence of deposits in the mesangium and/or mesangial cell proliferation; membranous glomerulonephritis (4 patients), cirrhotic glomerulosclerosis (2 patients); and lupuslike glomerulonephritis (3 patients). Glomerular diseases seemed to be significantly associated with chronic hepatitis or liver cirrhosis. Interstitial inflammation was present in 19 cases: chronic pyelonephritis (2 patients), focal nephritis (5 patients), multiple cortical abscesses (7 patients), granulomatous nephritis (5 patients). Cryptococci were found in one and undetermined microorganisms in two cases of multiple cortical abscesses. Atypical mycobacteria were found in two cases of granulomatous nephritis. Mycotic infections were identified in another 6 patients, in whom they did not elicit any inflammatory response. It is worth stressing that, although various generalized infections are common in patients with acquired immunodeficiency syndrome, only cryptococci and atypical mycobacteria also frequently involve the kidney. Focal tubular necrosis was observed in 15 patients. Benign nephrosclerosis was the most common vascular change (27 patients). Changes recalling hemolyticuremic and localized intravascular coagulation were found in three and six patients, respectively. Our data, dealing with a European Caucasian population, considerably differ from those reported in North American literature, in as much as we found no cases of human immunodeficiency virus nephropathy. Conversely, immune-mediated glomerular diseases were frequent, in agreement with recent studies on renal biopsy specimens from AIDS patients with acquired immunodeficiency syndrome. This type of infections, supplies multiple sources of antigens that may stimulate immune complex formation and, therefore, glomerular diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1997

GAS6, the ligand of Axl and Rse receptors, is expressed in hematopoietic tissue but lacks mitogenic activity.

GAS6, a gene previously identified as growth arrest specific, has been demonstrated to be the ligand of Axl, a novel tyrosine kinase receptor widely expressed in both normal and neoplastic hematopoietic tissue. We have observed previously that GAS6 mRNA was present in whole bone marrow. This preliminary finding prompted us to investigate the presence of GAS6 in hematopoietic tissue and the possible role of this molecule in controlling the proliferation of hematopoietic precursors. We report here that the protein GAS6 is diffusely present in hematopoietic tissue, both in stromal and in hematopoietic cells, and that, among these cells, positivity is observed in megakaryocytes and myelomonocytic precursors. Furthermore, our data suggest that GAS6 is not a growth factor for hematopoietic progenitors or stromal fibroblasts. Despite the fact that both the Axl receptor and its ligand, GAS6, are expressed in hematopoietic tissue, the biological role of their interactions remains to be determined.

Biopsy↗
PubMed1996

Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas.

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.

Chromosome Deletion↗
PubMed1996

Simulation of right atrial cardiac myxoma by silent hepatocellular carcinoma.

A clinically silent hepatocellular carcinoma presenting as a mixoma of the right atrium is described. Intra-atrial growth has been reported in advanced, clinically manifested cases of liver carcinomas in African and Japanese subjects, but very occasionally in Caucasian people. Our case further suggests that this occurrence should also be considered in Western Countries.

Aged↗
PubMed1996

Intracellular protozoan infection in small intestinal biopsies of patients with AIDS. Light and electron microscopic evaluation.

Small intestinal biopsies of 21 patients with acquired immunodeficiency syndrome (AIDS) with light microscopic findings diagnostic or suspicious for parasite infection were investigated by transmission electron microscopy (TEM). TEM allowed us to identify and specify the genus and species of involved parasites in 16 out of the 21 cases: 7 Cryptosporidium parvum, 5 Enterocytozoon bieneusi and 4 Isospora belli. Cryptosporidium was easily identified on light microscopy (LM), and only slightly influenced by parasite burden in all the 7 cases; TEM confirmed LM diagnosis and made it possible to characterize the parasites as C. parvum. The identification of Microsporidium on LM in our cases was related to the burden of parasite; its presence was certainty identified in 2 cases and suspected in 3. TEM allowed to identify these parasites as E. bieneusi. Intracytoplasmic coccidia could be detected with certainly in semithin sections in all 4 cases, but TEM was always needed to specify the infectious agent as I. belli. In 5 cases the suspicious of protozoan infection on LM (3 microsporidia, 1 intracytoplasmic coccidia and 1 Cryptosporidium) was not confirmed by TEM. Our data suggest that TEM is an appropriate diagnostic tool in this field of pathology and necessary in most of the cases.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Pattern of glomerular involvement in human immunodeficiency virus-infected patients: an Italian study.

Renal biopsy specimens from 26 adult human immunodeficiency virus (HIV)-infected patients with glomerular involvement were reviewed from the files of three hospital pathology services in Northern Italy. All the patients were Italian and most (19 of 26 patients) were intravenous drug addicts. The types of glomerular lesions were as follows: minimal-change glomerulopathy (two cases), mesangial proliferative glomerulonephritis (GN) with scanty immunoglobulin deposits (four cases), and various patterns of immune complex-mediated glomerulonephritis, including postinfectious GN (six cases), membranoproliferative GN (one case), membranous GN (three cases), immunoglobulin (Ig) A nephropathy (four cases), a mixed membranous and proliferative (three cases) and diffuse proliferative lupus-like pattern with subendothelial deposits, and intraluminal thrombi (two cases) or subepithelial and subendothelial deposits (one case). None of the patients had evidence of HIV-associated nephropathy. Our study confirms previous observations on the low incidence of HIV-associated nephropathy among white HIV-infected patients in Europe, where immune complex-mediated GN seems to predominate. Apart from the frequent electron microscopic observation of endothelial tubuloreticular structures, none of the reported lesions could be distinguished on morphologic grounds from those occurring in uninfected patients. The high variability of the glomerular lesions upholds the need for accurate diagnosis for the clinician confronted with an HIV-positive patient with suspected glomerular involvement.

Adult↗
PubMed1995

Glomerulopathy associated with predominant fibronectin deposits: a newly recognized hereditary disease.

A newly recognized type of familial glomerulopathy observed in patients of both sexes in six families is reported. Proteinuria, often within the nephrotic range, microscopic hematuria, hypertension and a slowly decreasing renal function over several years were common. No underlying systemic diseases were identified. Generally, light microscopy showed enlarged glomeruli with minimal hypercellularity and with extensive deposits in the mesangium and subendothelial space. By electron microscopy, granular deposits with some admixture of fibrils were most common. In one family, the deposits were predominantly fibrillary. Immunoglobulins and complement factors were inconstant or lacking. A main finding was a strong immune reactivity to fibronectin, corresponding to the distribution of the deposits. In one patient, the deposits recurred in a renal transplant. There was no indication of systemic deposition. Abnormalities in the metabolism of circulating fibronectin may play a pathogenetic role in this disease of probably autosomal dominant inheritance.

Adolescent↗
PubMed1995

Acute hepatic and renal failure caused by Pneumocystis carinii in patients with AIDS.

Clinical and pathological findings are described in two AIDS patients with Pneumocystis carinii infection who received prophylactic treatment with nebulised pentamidine and developed unusual hepatic and renal failure. Histological examination showed clumps of P carinii massively obstructing hepatic sinuses and portal vessels in the first patient, and merular and intertubular capillaries in the second. These findings could explain the unusual clinical features, characterised by acute hepatic and renal failure.

AIDS-Related Opportunistic Infections↗
PubMed1995

Benign recurrent intrahepatic cholestasis. Some reflections on a case followed for 20 years.

Benign recurrent intrahepatic cholestasis (BRIC) is a form of cholestasis of obscure aetiology characterized by recurrent episodes of jaundice and itching associated with a morphological picture of pure intrahepatic cholestasis. No effective treatment has yet been found among the many that have been proposed and the invariably benign nature of the condition has been questioned. A case of BRIC followed for a period of 20 years is described. This case is of great interest from these two points of view: 1) the histologic and electron microscopic findings 23 and 41 years after the first episode of cholestasis, respectively, failed to reveal evidence of the possible future development of cirrhosis; 2) treatment with ursodeoxycholic acid proved ineffective both therapeutically and in the prevention of episodes of bile stasis: on the contrary, calculosis of the common bile duct appeared after 8 months from the onset of the treatment.

Age Factors↗
PubMed1994

Renal and hepatic angiomyolipomas in a child without evidence of tuberous sclerosis.

A renal neoplasia, displaying the typical features of angiomyolipoma (an admixture of smooth muscle cells, mature adipocytes and tangles of thick-walled blood vessels) was found in a nine-year-old boy. In addition, cytoplasmic crystalloid structures and HMB 45 positivity were found in smooth muscle cells. Similar findings were also observed in a small nodule of the liver. According to literature data, angiomyolipoma is very rare in children and almost exclusively associated with tuberous sclerosis. Our case suggest that the diagnostic hypothesis of angiomyolipoma can not be disregarded when a renal mass is identified in a young patient even in a clinical setting other than tuberous sclerosis.

Angiomyolipoma↗
PubMed1993

Light microscopic and immunohistochemical evaluation of vascular and neural invasion in colorectal cancer.

One hundred and sixty consecutive surgically removed colorectal carcinomas were investigated on histological sections stained with Hematoxylin and Eosin (H & E). Vascular and neural neoplastic invasion was found in 49 (30.6%) and 50 (31.3%) patients. In addition, immunohistochemical investigation was performed on step sections to those stained with H & E in the first 50 patients, using anti-human Factor VIII related antigen, anti-actin and anti-protein S 100 antisera. The percentages of positive cases for vascular invasion in this group of 50 patients were 20% on H & E sections and 62% on those stained with anti-Factor VIII and anti-actin antisera. Neural infiltration was identified in 14% of cases on H & E sections and in 70% of cases on anti-protein S 100 treated sections. Since vascular and neural infiltration are known to be ominous prognostic factors, their identification has great clinical relevance. The use of these simple immunohistochemical stains, using readily available antisera on formalin-fixed material, is recommended as routine procedure in surgical pathology laboratories.

Adult↗
PubMed1993

Immunotactoid glomerulopathy (ITGP): a not fully defined clinicopathologic entity.

Immunotactoid glomerulopathy is characterized by the ultrastructural finding of fibrillary or microtubular deposits in patients without systemic diseases such as SLE, diabetes, paraproteinemias, cryoglobulinemia, or amyloidosis. These deposits correspond in most (but not all) cases to immunoglobulin and complement deposits as shown by immunohistochemical techniques. Different light microscopic patterns (mesangioproliferative, membranous, membranoproliferative, and crescentic) have been reported. Clinical presenting feature is characterized by proteinuria (often of nephrotic range), hematuria, and hypertension in most cases. Chronic renal failure requiring hemodialysis or transplantation is described in more than half the patients. Pathogenesis has not yet been elucidated and only some speculative hypotheses have so far been suggested. At present there is no clear evidence that we are dealing with a new pathologic entity, but larger series must be collected and studied in order to find a correct taxonomic collocation of this glomerulopathy.

Adult↗
PubMed1993

Membranous glomerulonephritis (MGN) in transplanted kidneys: morphologic investigation on 256 renal allografts.

Twenty-two cases of membraneous glomerulonephritis (MGN) were identified among 256 bioptically investigated transplanted patients. MGN was defined as de novo in 15 patients and recurrent in three. The type of MGN could not be ascertained with certainty in the other four. Several morphologic features unusual for the idiopathic form of MGN were found. Most cases disclosed focal segmental distribution of subepithelial deposits and showed the contemporaneous presence of different stages of the disease according to Ehrenreich and Churg classification. In addition mild-to-moderate mesangial cell proliferation was found in about one third of de novo MGN biopsies. Endocapillary hypercellularity was observed in 14 specimens and held to be due to an excess of mononuclear blood cells, related to a concomitant episode of rejection. Chronic transplant glomerulopathy was found in 47% of patients with de novo MGN and in 66% of those with recurrent MGN, being more frequently observed in specimens with diffuse distribution of deposits. Repeated biopsies showed progression of the stage and extension of deposits to a large number of capillary loops in four out of six patients. De novo MGN was documented 1 to 54 mo (mean value 20.2 mo) after transplantation, and the recurrence was observed after 12, 15, and 42 mo. All but two patients (who were anuric) complained of proteinuria, which was in the nephrotic range in 12. Apart from the significantly higher frequency in de novo MGN patients of DR4 antigen, whose significance must in any case be re-evaluated in a larger series, none of the factors so far suggested to be linked to the onset of de novo MGN has found further support in our study. On the contrary, relevance in favoring the appearance and the evolution of MGN has to be attributed to transplant glomerulopathy, which, moreover, seems to be more important than MGN itself in causing the unfavorable outcome of the graft.

Adult↗
PubMed1992

Glomerulonephritis with organized deposits: a mesangiopathic, not immune complex-mediated disease? A pathologic study of two cases in the same family.

Similar glomerular changes (marked widening of the mesangial stalk, irregular basement membrane thickening, and presence of mesangial and subendothelial deposits) were observed by light microscopy in renal biopsy specimens from two patients (mother and daughter) affected by nephrotic syndrome. Electron microscopy disclosed huge glomerular electron-dense deposits containing 12-nm fibrils in both patients. Immunohistochemical investigations performed with antisera anti-immunoglobulin (Ig) and anti-complement fractions, anti-laminin, anti-collagen IV, and anti-fibronectin (FN) showed scant and focal Ig and complement deposits and strong deposits of FN in the mesangium and along glomerular basement membranes. Most glomerular FN was plasma-derived, as shown by immunohistochemical tests with monoclonal antibodies specific for both plasma and cell-derived FN (IST-4) and for cell-derived FN (IST-9). Electron-dense deposits with fibrillar component could hardly correspond to the Ig and complement deposits, whereas they could be related to FN deposits. Since it is known that in glomeruli FN binds to Ig and immune complexes, and the latter seem to be too scant to justify light and electron microscopic lesions and clinical findings, the hypothesis of a primary mesangiopathic glomerulonephritis in some way connected with abnormal plasma FN deposition within the glomeruli and subsequent non-specific immune reactant entrapment could be considered. We could be dealing with a peculiar form of fibrillary glomerulonephritis with rather indolent evolution, as shown by a slow decrease of glomerular function and the scarcely modified glomerular changes found in the second biopsy performed in the mother 8 years after the first investigation.

Adolescent↗
PubMed1992

Immunohistochemical distinction between amyloidosis and fibrillar glomerulopathy.

Six patients with glomerulonephritis and glomerular proteinaceous deposits constituted by fibrillar ultrastructures similar to those of amyloid but lacking the Congo red tinctorial affinity characterizing amyloid were studied. Clinically, these patients had proteinuria and hematuria; in addition, three patients had hypertension and one renal failure. Protein deposits in their kidney biopsy sections were evaluated by immunofluorescence, immunoperoxidase, and immunoelectron microscopic (protein A-gold) techniques, using antibodies against IgG, IgA, IgM, C3, C1q, fibrinogen, immunoglobulin kappa and lambda light chains, and against amyloid fibril proteins of different types, including AA, A lambda, A kappa, and AF. By immunofluorescence and immunoperoxidase, in all cases the deposits stained intensely with antibodies against IgG, C3, and kappa and lambda light chains; one case also showed C1q immunoreactivity. By contrast, none stained with antibodies against various amyloid fibril proteins. Immunoelectron microscopic findings corroborated this data, indicating that the nonamyloid fibrillar deposits studied are antigenically distinct from known amyloid deposits and that they contain IgG-derived material.

Amyloid↗