The properties and development of conchoidal bodies in sarcoid and sarcoid-like granulomas

In vivo antileishmanial activity and histopathological evaluation in Leishmania infantum infected hamsters after treatment with a furoxan derivative

N-oxide derivatives compounds such as furoxan and benzofuroxan are promising scaffolds for designing of new antileishmanial drugs. A series of furoxan (1,2,5-oxadiazole 2-N-oxide) (compounds 4a-b, and 14a-f) and benzofuroxan (benzo[c][1,2,5]oxadiazole1-N-oxide) (compounds 8a-c) derivatives were evaluated against in vitro cultured L. infantum promastigotes and amastigotes. The compounds exhibited activity against promastigote and intracellular amastigote forms with EC₅₀ values ranging from 2.9 to 71.2μM and 2.1 to 18.2μM, respectively. The most promising compound, 14e, showed good antileishmanial activity (EC₅₀=3.1μM) against intracellular amastigote forms of L. infantum with a selectivity index, based on murine macrophages (SI=66.4), almost 3-times superior to that presented by the standard drug amphotericin B (AmpB). The efficacy of 14e to eliminate the parasites in vivo was also demonstrated. Treatment of L. infantum-infected hamsters with compound 14e at 3.0mg/Kg/day led to a meaningful reduction of parasite load in spleen (49.9%) and liver (54.2%), respectively; these data were corroborated by histopathological analysis, which also revealed reduction in the number of inflammatory cells in the liver of the treated animals. Moreover, histological analysis of the spleen and kidney of treated animals did not reveal alterations suggestive of toxic effects. The parasite load reduction might be related to NO production, since this molecule is a NO-donor. We observed neither side effects nor elevation of hepatic/renal biomarker levels in the plasma. The data herein presented suggest that the compound should be considered in the development of new drugs for treatment of visceral leishmaniasis.

Light- and electron-microscopic studies on multinucleated giant cells in sarcoid granuloma: new aspects of asteroid and Schaumann bodies

Ultrastructural studies using transmission, analytical, electron, and light microscopy were performed on epithelioid granulomata in 4 lymph nodes from a case of sarcoidosis, emphasizing the organization of asteroid and Schaumann bodies in multinucleated giant cells and the deposition of chemical elements. Serial sectioning at semithin level showed a single multinucleated giant cell can contain up to 4 asteroid and 1 Schaumann body. Microtubules and centrioles were not found in asteroid bodies, although a centriolar field was present in 1 giant cell close to the plasma membrane, completely unrelated to the asteroid body. In 1 asteroid body, tubulelike structures were observed in a focus showing filament dissociation. A principal ultrastructural finding is intimate envelopment of radiating filamentous arms of the asteroid body by myelinoid membranes, extensive forms of which are also present between the arms. Elemental analysis revealed a definite peak of calcium and a probable phosphorus peak in relation to the asteroid body and associated myelinoid membranes. Calcium and phosphorus with smaller quantities of aluminum and iron were found in Schaumann bodies. Our studies indicate that organization of the asteroid body is more complex than hitherto described, independent of the centriolar and microtubular systems. Evidence for the possible developmental pathway of the Schaumann body is provided by morphological changes within myelinoid figures intimately related to the asteroid body.

Beryllium disease

The increasing use of beryllium in a variety of industries continues to be a hazard. New cases are still being reported to the UK Beryllium Case Registry, now numbering 60 in the period 1945-1988. The majority of cases follow inhalation which results in acute beryllium disease (chemical pneumonitis) or more commonly chronic beryllium disease--a granulomatous pneumonitis. Granulomatous skin nodules also occur following local implantation. The clinical and radiological features are briefly described with the emphasis on pathology and immunology. Laser microprobe mass spectrometry analysis of tissue sections is a major advance in diagnosis. Detection of beryllium distinguishes the granulomas of chronic beryllium disease from other diseases, in particular sarcoidosis. The role of beryllium lymphocyte transformation tests is discussed. Chronic beryllium disease is steroid dependent and local excision of skin lesions appears to be curative. There is no evidence that beryllium is carcinogenic.

Granulomatous inflammation--a review

The granulomatous inflammatory response is a special type of chronic inflammation characterised by often focal collections of macrophages, epithelioid cells and multinucleated giant cells. In this review the characteristics of these cells of the mononuclear phagocyte series are considered, with particular reference to the properties of epithelioid cells and the formation of multinucleated giant cells. The initiation and development of granulomatous inflammation is discussed, stressing the importance of persistence of the inciting agent and the complex role of the immune system, not only in the perpetuation of the granulomatous response but also in the development of necrosis and fibrosis.

Sarcoidosis--1977

Sarcoidosis is defined as a multisystem disorder characterised by the finding of epithelioid cell granulomas in more than one system. Diagnosis is aided by the use of the Kveim Siltzbach skin test and the development of an "in vitro" Kmif test is discussed. Despite extensive researches the causative agent(s) remains unknown. The granulomas, morphologically, on light and electron microscopy and histochemistry may be indistinguishable from those caused by known agents. Inclusion bodies are also non specific. Central necrosis is rare, and can be usually distinguished from caseation. The close relationship between the monocyte derived, epithelioid cells and lymphocytes is emphasised. Evidence is accumulating that epithelioid cells in sarcoid type granulomas are primarily synthesising rather than phagocytic cells. The products are considered to be mucoglycoproteins and may have both local and systemic actions. Locally it is suggested that the products may be lymphokines which react with associated thymic derived (T) lymphocytes and mononuclear cells and thus play a role in perpetuating the granulomas. Epithelioid cells may also be a source of circulating T lymphocyte function depressants. It has further been suggested that epitheloid cells are the source of the raised angiotensin converting enzyme found in sarcoid sera. Study of epithelioid cell granulomas in sarcoidosis, despite the disappointing lack of evidence of a causative sarcoid agent(s), is thus of considerable interest in furthering knowledge of many diseases characterised by these curious cellular foci.

Pulmonary sarcoidosis: A clinico-pathological study

The light and electron microscopic changes in biopsy tissue from the lung of a 30-year-old housewife severeley incapacitated by diffuse pulmonary sarcoidosis with pulmonary hypertension are presented. The lung tissue was distorted by numerous granulomas in the interstitial tissues and within alveoli. Many pulmonary blood vessels including arteries were damaged by the granulomas. The ultrastructural features of the epithelioid cells were found to be distinctive and probably specific. The giant cells which accompanied the epithelioid cells contained two types of inclusion body: one appeared to be related to the Schaumann body but the nature and origin of the second type was not clear. Many of the granulomas were surrounded by avascular fibrous tissue which contained, in addition to mature fibroblasts, myofibroblasts and a primitive form of cell that appeared to be a fibroblast precursor. It was conjectured that the myofibroblasts, through their contractile powers, might increase the distortion of the lung architecture and thereby the patient's disability. The alveolar walls were thickened by a diffuse infiltrate of macrophages and epithelioid cells but there was no excess of collagen and elastic fibres. The evidence suggested that the epithelioid cells developed from macrophages. From the cellular nature of the diffuse infiltration of the alveolar walls and the absence of fibrosis it seemed that the disease was still at an early and active stage, a conclusion strengthened by the fact that treatment with corticosteroids led to marked and sustained clinical improvement.