Lymphadenitis, trans-epidermal elimination and unusual histopathology in human rhinosporidiosis.

From a study of rhinosporidial tissues of 64 human cases of ocular, urethral and nasopharyngeal disease, unusual histopathological features of 27 cases are described. Histopathological evidence of lymphadenitis in rhinosporidiosis is presented for the first time. The phenomenon of 'trans-epidermal elimination' of sporangia of the causative pathogen Rhinosporidium seeberi is illustrated and it is argued that this phenomenon is rather the pathogen's mechanism for endospore-dispersal than a non-specific defence reaction of the host as has previously been suggested. Other unusual appearances described include variations in the intensity and composition of the host-cell infiltrate in tissues from different patients and in different portions of the same tissue, pitfalls in histopathological diagnosis, and unusual appearances of the pathogen. Histopathological clues to the pathogenesis of rhinosporidiosis and mechanisms of anti-rhinosporidial immunity in the host are discussed, illustrating the probable occurrence of immunesuppressive reactions to account for the variations in the density and composition of the host-cell infiltrate and the state of the rhinosporidial sporangia--intact or degenerate--, relating these variations to the chronicity, recurrences and systemic dissemination of rhinosporidiosis.

Omental cryptococcoma. An unusual presentation of cryptococcosis.

A case of an omental cryptococcal granuloma, believed to be the first reported, presented as an abdominal mass in a 29-year-old man. An exploratory laparotomy revealed a soft, 8-cm lesion in the omentum. Pathologic examination showed this to be a cryptococcal granuloma containing masses of budding, encapsulated yeasts. Aggregates of eosinophils were also noted. This case is unusual in both site (as cryptococcosis tends to localize in the central nervous system) and size.

Studies of medicinal plants of Sri Lanka. Part 14: Toxicity of some traditional medicinal herbs.

Seventy five medicinal plants of the traditional Ayurvedic pharmacopoeia of Sri Lanka have been screened chemically for alkaloids and pyrrolizidine alkaloids. Of these, Crotolaria juncea L. was found to contain pyrrolizidine alkaloids with biological effects consistent with pyrrolizidine alkaloid toxicity. Feeding trials in rats with three plants lacking pyrrolizidine alkaloids, namely Aegle marmelos (L.) Corr., Hemidesmus indicus (L.) Ait. F. and Terminalia chebula Retz. produced hepatic lesions which included central vein abnormalities while Terminalia chebula and Withania somnifera (L.) dunal produced marked renal lesions.

An epizootic of Klebsiella aerogenes infection in laboratory rats.

Klebsiella aerogenes was identified as the pathogen in an epizootic of single and multiple abscesses in the cervical, axillary and inguinal regions in laboratory rats. Involvement of the salivary glands in the inflammatory tissue in some cases produced interlobular and interacinar fibrosis resembling "fibroadenosis'. Similar lesions were reproduced with a strain of Klebsiella aerogenes isolated from a diseased rat. Oral carriage of the same strain was detected in the diseased rats, and in normal rats of the same stock. Lymphadenitis appears to have been the primary lesion.

Studies on medicinal plants of Sri Lanka: occurrence of pyrrolizidine alkaloids and hepatotoxic properties in some traditional medicinal herbs.

There is a paucity of data on the occurrence of hepatotoxic and hepatocarcinogenic pyrrolizidine alkaloids in medicinal plants, and there are no data on the hepatotoxic properties of herbal medicines that are used in the traditional pharmacopoiea of Sri Lanka and other Asian and African countries. In view of the extensive consumption of these herbs and the occurrence of chronic liver diseases including hepatocellular cancer in this and other countries of South Asia, we have screened fifty medicinal plants for pyrrolizidine alkaloids and have obtained positive results with three species, namely Crotalaria verrucosa L., Holarrhena antidysenterica (L.) Br., and Cassia auriculata L. Feeding trials in rats with materials from these three species produced liver lesions--disruption of the centrilobular veins, congestion or haemorrhage in the centrilobular sinusoids, centrilobular or focal hepatocellular necrosis--and histopathology in the lungs and kidneys which were compatible with the action of pyrrolizidine alkaloids. The presence of alkaloids in C. auriculata has not been previously reported nor has the presence of pyrrolizidine alkaloids in H. antidysenterica. It is suggested that the consumption of herbal medicines that contain pyrrolizidine alkaloids could contribute to the high incidence of chronic liver disease including primary hepatocellular cancer in Asian and African countries.

Pathogenesis of necrotising enteritis with special reference to intestinal hypersensitivity reactions.

The aetiological aspects of 83 sporadic cases of necrotising enteritis (NE) have been studied. Of 56 cases in which histology of the intestine was possible, eight showed appearances (oedema and local eosinophilia) suggestive of a type I hypersensitivity reaction, while in 37 the appearances were suggestive of a type III reaction. We suggest that these reactions, which were more common in children and young adults, were initiating factors in the intestinal necrosis. The type III reactions (submucosal arteritis, fibrinoid necrosis of arteriolar walls, intramural and perivascular infiltration with polymorphonuclear, mononuclear, and eosinophil cells, and submucous oedema) were in seven cases accompanied by extraintestinal lesions (hypercellularity of glomeruli, amorphous material in the Bowman's capsular space, tubular casts, mononuclear cell infiltration into the hepatic portal tracts, congestion and oedema of the lung) which were compatible with systemic immune complex disease. The mesenteric lymph nodes in 12 out of 15 cases with intestinal arteritis showed appearances indicative of a humoral immune response. We suggest that NE is a two-stage process. In stage 1, a necrotic focus is established in the intestinal mucosa-submucosa by 'initiating' factors of vascular (functional or organic) or microbial (exotoxic, endotoxic, or Shwartzman) origin. Functional circulatory insufficiency in the intestine is of particular relevance to necrotising enteritis in neonates and in adults with traumatic shock or cardiac insufficiency. The jejunal and--to a lesser extent--the ileal microcirculation appear to be particularly vulnerable to microcirculatory insufficiency. Ninety-seven per cent of our cases were of NE of the small intestine of which 76% involved the jejunum alone or as a part of a jejunoileitis. These 'initiating' factors act either singly or synergistically with 'promoting' factors (changes in the volume, composition, or pH of the diet, intestinal stasis, or bacterial factors) in the establishment of necrotic foci in the intestine. Stage 2 results from the colonisation of the necrotic foci by intestinal clostridia, the toxigenic capacity of which will determine the progress of the intestinal lesion. Clinically established NE is essentially gas gangrene of the intestinal wall. Our bacteriological findings (microscopic, cultural, and serological) support a pathogenetic role of Cl. welchii in the established stages of necrotising enteritis. Strains of Cl. welchii from NE cases had significantly higher histidine decarboxylase activity than strains from control sources; it is possible that the resultant histamine production could act as a promoting factor in stage 1. Neutralising antibody against the Wanowrie virus, an Asian arbovirus which produces haemorrhagic enteritis in mice, was absent in the paired sera from 10 cases examined.

Veno-occlusive lesions in the liver of rats after prolonged feeding with palmyrah (Borassus flabellifer) flour.

Flour from the young shoot of the palmyrah palm (Borassus flabellifer) which is consumed by people in certain tropical countries, when fed for prolonged periods to adult male rats produced chronic hepatic lesions which included intraluminal fibrosis of the centrilobular and portal veins, bile duct proliferation, increase of reticulin and fibrosis. Thromboses of the hepatic veins was not seen. The vascular lesions commenced as a subendothelial swelling which projected into the lumen and in which collagen deposition ended in almost total obliteration of the lumen. No hepatic megalocytosis was seen. It is suggested that the toxic factor(s) responsible are different from the pyrrolizidine alkaloids and dimethylnitrosamine which have been well documented to produce similar lesions.

Leiomyosarcoma of the mediastinum.

A case of leiomyosarcoma of the posterior mediastinum is presented; 2 other malignant and 7 benign smooth muscle tumours of the mediastinum have been collected from the literautre. The tendency for blood-borne and local recurrence in the leiomyosarcomas is demonstrated. Various theories for the origin of these tumours are examined.