Biomedical subjects

A O Muda

Publications and source records attributed to A O Muda.

29 records · Page 2Linked to original sources

PubMed1995

Lipoid proteinosis: clinical, histologic, and ultrastructural investigations.

The case of a 12-year-old boy with lipoid proteinosis is reported. Physical examination revealed long-standing varicella-like scars and areas of hyperpigmentation on the face and upper limbs with no evidence of photosensitivity, hoarseness, small papules along the free margins of eyelids, tongue firmness with short frenulum, and widespread papular lesions of the oral cavity. Histologic and ultrastructural examination revealed the characteristic skin changes: pink, hyaline-like, strongly periodic acid-Schiff-positive material in the dermis, surrounding blood vessels, and sweat glands; thin (30 to 35 nm) collagen fibrils interspersed in abundant amorphous material; blood vessels surrounded by thickened, multilayered basement membranes, in which layers of typical, homogeneous basement membrane material were alternating with electronlucent areas filled by various amounts of thin, cross-striated fibrils, arranged perpendicularly. These findings are of great interest since they show a complex relationship between type IV and type III-like collagen components.

Child↗

PubMed1994

Glomerular hypertrophy and chronic renal failure in focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis evolves toward chronic renal failure (CRF) with a highly variable rate; in particular, a group of patients with a much more rapid decline of renal function has been described. The purpose of this study was to evaluate the usefulness of morphometry in identifying those cases with a faster decline in renal function. Two groups of patients have been studied: six with rapid evolution toward CRF (group 1) and six without reduction in renal function during a follow-up of up to 10 years (group 2). The results of the morphometric analysis of glomeruli were as follows: mean glomerular area: 30,550 +/- 5,259 microns2 (group 1) versus 22,667 +/- 5,078 microns2 (group 2) (P = 0.01); maximum glomerular area: 40,827 +/- 9,508 microns2 (group 1) versus 30,445 +/- 7,224 microns2 (group 2) (P = 0.02); mean glomerular diameter: 193.9 +/- 15.8 microns (group 1) versus 161.8 +/- 16.8 microns (group 2) (P = 0.003); and caliper diameter: 328.6 +/- 20.6 microns (group 1) versus 260.6 +/- 36 microns (group 2) (P = 0.001). Values of body surface area were not different between the two groups (1.85 +/- 0.34 m2 v 1.6 +/- 0.13 m2) (P = NS). Our results suggest that glomerular hypertrophy in the course of focal segmental glomerulosclerosis is correlated with a faster decline toward CRF. It might represent a compensatory hypertrophy that would immediately precede a rapid decline in renal function or it might be the expression of the preexisting condition (meganephronia), which predisposes to the development of CRF.

Adult↗

PubMed1991

Fibrosarcoma of the thymic region. A case report.

Fibrosarcoma of the mediastinum is an unusual tumor and only few cases have been reported. We describe the clinical and pathologic findings of a case of mediastinal mass in a 34 year old woman. The histologic, histochemical, immunocytochemical and ultrastructural features of the tumor were consistent with a diagnosis of fibrosarcoma. Furthermore, the tumor displayed evidence of close relations with the thymus capsule; the possibility that it may arise from the thymic stroma is considered. The differential diagnosis of spindle cell tumors of the mediastinum is also discussed.

Adult↗

PubMed1991

Physico-chemical analysis of resorcin-fuchsin reagents and its relevance to staining quality of elastic fibres.

Three Weigert's resorcin-fuchsin reagents for elastic fibres were prepared by using different lots of basic fucsin and by preparing the staining solutions with ferric chloride or ferric perchlorate. The solutions were analyzed by spectrophotometry, thin layer chromatography (TLC) and spectrofluorimetry. Their ability to stain elastic fibres was tested on several human tissue. The strongest stain and faintest background were obtained with the fuchsin-chloride reagent, which showed the most significant reduction of the absorption at 575 nm by spectrofluorimetry, associated with an increased absorption at 510 nm with respect to the other stains. The results showed that physico-chemical analysis can represent a reliable, although empirical, way to predict the usefulness of a resorcin-fuchsin reagent for histological work.

Chromatography, Thin Layer↗

PubMed1990

Use of freeze-drying technology for the study of renal biopsies.

Adequate handling of renal biopsies requires processing for light and electron microscopy, as well as for immunohistochemical study. Problems of adequate sampling are frequently encountered, and tissue size can be insufficient, since morphologic examination requires chemical fixation, while immunofluorescence study is currently performed on snap-frozen, cryostat-cut tissue. The application of freeze-drying technology on 20 renal needle biopsies has been investigated to assess the feasibility and reliability of the technique as a routine diagnostic tool in renal pathology. Morphologic as well as immunohistochemical studies were performed on freeze-dried, paraffin-embedded specimens, including immunofluorescence and PAP techniques to detect immunoglobulins, complement fractions, fibrinogen, collagen types, and laminin. Our results showed good preservation of tissue morphology, similar to standard formalin fixation. Moreover, absence of diffusion artifacts and intensity of immunohistochemical reactions were comparable to what is obtained with cryostat sections. We therefore suggest that freeze-drying before paraffin embedding is, at least for diagnostic purposes, preferable to formalin fixation; unfixed, cryostat-cut sections can still be informative and should be used whenever tissue is available in selected cases, and/or in experimental work.

Biopsy↗

PubMed1989

Ultrastructural histochemistry of mesotheliomas and adenocarcinomas in malignant effusions.

The results of electron microscopic examination of cytologic specimens from six cases of mesothelioma and 10 cases of metastatic carcinoma of different origins are presented. The formation of cell clusters in malignant effusions from the two neoplasms has been thoroughly investigated: in mesotheliomas, cells had longer, more slender microvilli than in carcinomas and more abundant bundles of intermediate filaments; the central cavity often seen in the clusters frequently contained collagen and showed basement membrane production. The application of periodic acid-silver methenamine (PASM) and phosphotungstic acid (PTA) demonstrated a peculiar ultrastructural difference in cell coat staining in the two tumor types: in mesotheliomas, PTA and PASM were consistently negative along the outer surface of the cell aggregates, while carcinomas displayed a positive reaction either on the outer surface or on both inner and outer surfaces of the clusters. The diagnostic significance of the above-mentioned difference between the two neoplasms will require further investigation in a larger number of cases.

Adenocarcinoma↗

PubMed1988

Ultrastructural histochemical investigations of "dense deposit disease". Pathogenetic approach to a special type of mesangiocapillary glomerulonephritis.

Dense deposit disease is characterized by the presence of intramembranous dense deposits; their constituents are unknown but immunological and biochemical studies have demonstrated that they contain no gamma-globulins or any other plasma protein. In order to clarify the nature of the dense deposits better, we investigated their most distinctive character, (marked electron-density) by means of ultrastructural histochemistry techniques using thin sections from Formaldehyde fixed, OsO4 postfixed and Epon embedded specimens collected for diagnostic electron microscopy. The dense deposits have a higher osmium affinity than the lamina densa of normal basement membranes, and the electron-density is strictly osmium-dependent suggesting the presence of a lipid component. Further data, obtained using an extraction method for lipids, seems to confirm our hypothesis.

Adolescent↗

PubMedDate not supplied

Morphological evidence of neutrophil-tumor cell phagocytosis (cannibalism) in human gastric adenocarcinomas.

The phenomenon of neutrophil-tumor cell emperipolesis or phagocytosis has been documented by light microscopy in various human carcinomas, but little is known about the cellular pathological processes and the morphological changes involved. In an attempt to clarify the nature of this phenomenon, the authors' ultrastructural studies on the relationships among neutrophils and tumor cells in human gastric carcinomas are reviewed and analyzed. At the electron microscopy level, apoptotic neutrophils were found within vacuoles of adenocarcinoma cells in 2 cases. They showed either early apoptotic morphology with perinuclear chromatin aggregation but cytoplasm integrity or late apoptotic morphology with uniform, collapsed nucleus and tightly packed cytoplasmic granules. A light microscopy review of 200 cases of resected gastric carcinomas identified 22 cases (11%) that were characterized by neutrophil-tumor cell phagocytosis (cannibalism). TUNEL staining confirmed the presence of apoptotic neutrophils within the cytoplasm of the tumor cells. This study provides light and electron microscopic evidence of apoptotic neutrophils phagocytosed by gastric adenocarcinoma cells. The morphological features of neutrophil-tumor cell phagocytosis (cannibalism) would suggest a particular mechanism of tumor-immune escape in human gastric carcinoma.

Adenocarcinoma↗

PubMedDate not supplied

IgA nephropathy: multivariate statistical analysis aimed at predicting outcome.

BACKGROUND: Several risk factors of IgA nephropathy (IgAN) have been identified, but their importance in predicting outcome is still controversial. METHODS: We conducted a retrospective study on 119 patients (pts) with IgAN. All had a follow-up of over five years (mean 134+/-56 months). For each patient we recorded age, 24h proteinuria, hematuria, renal function (RF), arterial hypertension (AH) and histological features. Multivariate analysis was done for predictive purposes (segmentation, using Chi-squared Automatic Interaction Detection-CHAID). RESULTS: AH at the time of renal biopsy was the principal and independent predicting factor: 30/50 (60%) hypertensive pts had serum creatinine > or =1.5 mg/dL at the end of follow-up compared to 9/69 (13%) pts with normal blood pressure. Age was a further predictive parameter: 21/28 (75%) pts with AH and age over 39 years had reduced RF at the last examination. In this subgroup, 18/19 (95%) with evidence of tubulo-interstitial lesions showed a decline of RF. CONCLUSIONS: AH and age alone are significant prognostic factors; tubulo-interstitial lesions are an additional pointer to poor outcome in these pts. The algorithm obtained with segmentation analysis may be a guideline for prognosis in single patients with IgA nephropathy.

Adolescent↗

PubMedDate not supplied

Chondroblastoma of the rib presenting as an intrathoracic mass. Report of a case with fine needle aspiration biopsy, immunocytochemistry and electron microscopy.

We describe an unusual case of chondroblastoma of the rib, initially presenting as a mediastinal mass eroding a vertebra, in which the preoperative diagnosis was made by fine needle aspiration (FNA) cytology and confirmed by histology and electron microscopy of the surgical specimen. Cytologic study of the smears revealed osteoclastlike giant cells and dishesive, mononucleate tumor cells; sections of the paraffin-embedded, aspirated material showed the chondroid matrix and typical chicken wire calcific deposits. Supporting diagnostic evidence was provided by immunohistochemical demonstration of S-100 protein. Unusual features were the presence of intranuclear pseudoinclusions and cytoplasmic granular deposits, which proved to contain iron on histochemical staining, ultrastructural morphology and x-ray analysis. This case emphasizes the value of FNA cytology in providing a correct diagnosis of chondroblastoma as well as the utility of embedding the aspirated material for histologic, immunohistochemical and ultrastructural studies.

Adult↗

PubMedDate not supplied

Sepsis-induced acute renal failure: unusual clinical presentation.

We report 4 cases of sepsis-induced acute renal failure (ARF) with peculiar clinical presentation in which the renal biopsy was the only clue to a correct diagnosis. We observed 66 cases of ARF in a 4-year experience. Seven (11%) were associated with sepsis; in 3 of these (4.5%) a shock was present. Clinical picture of the remaining 4 cases (6%) was characterized by ARF with oligoanuria and proteinuria (> 2 g/L), fever, resistant to antimicrobial therapy, negative hemocultures and severe systemic symptoms. Such a presentation could suggest a non-infectious systemic disease; renal biopsies were carried out. Histological findings consisted of microabscesses of variable size in the interstitium and within the tubular lumina. A full-dose, broad-spectrum, i.v. antimicrobial therapy was started, with favourable outcome and recovery of renal function. Our clinical experience points out that the clinical picture of ARF in course of sepsis may be variable and that its relationship with septicaemia could not be readily discernible.

Acute Kidney Injury↗