I. D. Bowen

The historical analysis of aspirin discovery, its relation to the willow tree and antiproliferative and anticancer potential

Abstract.  For several millennia, the willow tree and salicin have been associated with salicylic acid, the key precursor molecule that has contributed to the discovery of acetylsalicylic acid, traded as aspirin. These molecules have been shown to possess phyto‐ and chemotherapeutic activities as analgesic drugs. In recent decades, aspirin has become the focus of extensive investigation into antiproliferative and anticancer activities. The historical steps that led to the discovery of aspirin, and its antiproliferative and anticancer potential are highlighted in this review.

Proportions of mitotic and apoptotic cells in a range of untreated experimental tumours

Abstract. The quantitative aspect of apoptosis in experimental tumours is often neglected. In this study, the apoptotic and mitotic indices for a range of tumours have been determined at light microscope level. It has been found that the apoptotic levels fall into a consistent range for all tumour types and agree well with those described by previous workers. It is suggested that these might be basic parameters of tumour expansion, as relevant to growth kinetics as mitotic levels.

MODES OF CELL DEATH IN THE HYPOPHARYNGEAL GLAND OF THE HONEY BEE (APIS MELLIFERA L)

Different modes of cell death have been revealed in the regressing hypopharyngeal glands of worker honey bees. The hypopharyngeal gland, which is well developed in young nursing bees to produce protein for larval food, was seen to regress naturally in foraging adult worker bees. A range of techniques including histology, cytochemistry, in situ TUNEL, Annexin V and Comet assays indicated that cells within the gland demonstrate progressive symptoms of apoptosis, necrosis and a vacuolar form of programmed cell death. The latter mode of cell death did not display chromatin margination, but was accompanied by an enhanced level of autophagic and hydrolytic activity in which a cytosolic source of acid phosphatase became manifest in the extra‐cisternal spaces. Normal and annexin‐positive cells were found to occur in the younger nursing bees, whilst necrosis and an aberrant vacuolar type of apoptosis predominated in the older foraging bees. The relevance of these results to the classification of programmed cell death is discussed.

Histochemical characterization of cell death in honeybee larvae midgut after treatment with Paenibacillus larvae, Amitraz and Oxytetracycline.

A number of techniques were employed to assess cell death induced in honeybee larvae midgut afterper os inoculation of bacterium Paenibacillus larvae var. larvae, the causative agent of American foulbrood disease, and separately with acaricide Amitraz and antibiotic Oxytetracycline. In honeybee larvae exposed to Amitraz, which demonstrates both necrosis and apoptosis, cell death was found in 82% of midgut columnar and in 50% of regenerative epithelial cells, 24h after treatment. Cell death reduced to 36% in the epithelial cells, 48h after treatment. In Oxytetracycline‐treated larvae, cell death was identified in 40% of midgut epithelial cells, 24h after inoculation and increased to 55% over the next 24h. In Paenibacillus ‐infected larvae, all midgut epithelial cells died. Using ApopTag (Oncor) to label the multiple DNA ends generated by DNA fragmentation showed programmed cell death in 49% of columnar midgut cells 24h after Amitraz application. Cell death was reduced to 9% over the next 24h. Our data indicate that cell death could be identified and quantified in situ, using TUNEL techniques. This study also shows that the acaricide Amitraz is a trigger for programmed cell death in the midgut epithelial cells of honeybee larvae, unlike Paenibacillus which induces necrosis only. The data show that immunohistochemical methods are useful for studying in situ tissue pathology, and indicate possibilities for monitoring the effects of infective and chemical environmental stressors on cell death in honeybee larvae tissue.

Histopathological and histochemical changes in honeybee larvae (Apis mellifera L.) after infection with Bacillus larvae, the causative agent of American foulbrood disease.

Morphological, histochemical and cytochemical changes were examined in honeybee larvae after infection with the bacterium Bacillus larvae. The results indicate cell necrosis in the midgut epithelium accompanied by increasing cell vacuolization and nuclear pyknosis following per os inoculation with B. larvae. Many autolysosomes were positive for acid phosphatase. Non‐vacuolar acid phosphatase activity was also found in lysed cell compartments. No such activity was found in regenerative epithelial cells. Degradation of haemocytes, salivary glands and other tissues was also observed. Histochemical analyses after per cutaneous inoculation with B. larvae of three‐ and five‐day‐old honeybee larvae show intense non‐vacuolar acid phosphatase activity followed by disintegration of infected salivary glands, epithelial cell cytoplasm and haemocytes.

The fine structure of the planarianPolycelis tenuis (Iijima)

SummaryThe fine structure of the planarian epithelium, as revealed in stereo and transmission electron microscope studies, is described. The distribution of cilia and sensory receptors is examined and a new type of cup-shaped receptor is demonstrated. The extension of the parenchymal gland cells on to the epidermis is investigated, and the structure of the rhabdite-containing epidermal cells and associated basement membrane described. The origin of the epidermal cells in discussed.

The fine structure of the planarian Polycelis tenuis Iijima. II. The intestine and gastrodermal phagocytosis.

SummaryThe fine structure of the Minotian gland cell (spherical or granular club cell) and the phagocytic cell of the gastrodermis is described. The Minotian cells characteristically contain distinctive granules which are produced by the Golgi. Inclusion bodies containing membranous remains can also be found in the cytoplasm. The phagocytic cells bear groups of microvilli near adjacent junctions and have a much infolded basement membrane. Near the pharynx these cells contain the rod-shaped apical bodies found in the pharyngeal epithelium. Further into the intestine the cells more characteristically contain numerous phagocytic vacuoles and vacuolar dense bodies. After feeding, a consistent occlusion of the intestinal lumen has been observed. The columnar phagocytes have been shown to phagocytose cellular material and will also take up peroxidase and thorium oxide. The substances initially appear in the apical phagosomes. Acid phosphatase activity has been detected in the phagosomes after feeding. The enzyme is packaged in the Golgi and occurs in Golgi vacuoles and lysosomes of similar dimensions (morphologically vacuolar dense bodies). The fusion of lysosomes with phagosomes has been demonstrated histochemically.

Calcium salicylate-mediated apoptosis in human HT-1080 fibrosarcoma cells

Abstract.  Salicylates are novel biologically active compounds that exhibit multiple therapeutic activities. The anti‐cancer effectiveness of calcium salicylate has been investigated on human HT‐1080 fibrosarcoma cell lines at relatively low concentrations (predominantly 0.4 mm) compared to those previously reported. Although low calcium salicylate concentrations did not retard tumour growth progression significantly, as measured by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) and time‐lapse assays, its cytotoxic characteristics were proven to be prominent by various morphological and immunocytological techniques. The results here demonstrate evidence for approximately 25% apoptosis after treatment with calcium salicylate, which up‐regulatd the expression of p53, p21 and Bax, and down‐regulated Bcl‐2 in HT‐1080 cells.

The fine structural distribution of acid phosphatase in the digestive gland ofArion hortensis (Fer.)

SummaryAcid phosphatase activity has been found in association with the extensive brush border of the excretory cells and also within the lysosomal vacuoles of actively phagocytosing digestive cells. A release of enzyme into the cytoplasm occurs in some cells of the digestive epithelium. This appears to be linked with cellular lysis and may be a prelude to cell replacement.

In situ localization of heat-shock and histone proteins in honey-bee (apis mellifera l.) larvae infected with paenibacillus larvae

The immunohistochemical localization of the heat shock proteins (Hsp70 and Hsp90) and histone protein in healthy and Paenibacillus larvae infected honeybee (Apis mellifera L.) larvae has been studied. Hsp70 was found in the nuclei and the cytoplasm of infected midgut, salivary gland cells and haemocytes, but not in uninfected larvae. Hsp90 was localized in both infected and uninfected cells. Exposed histone proteins were localized in the nuclei of dying uninfected cells undergoing programmed cell death. The distribution of histone protein in uninfected cells of midgut, salivary gland, and other tissues was nuclear and indicative of normal programmed cell death at levels between 1 and 5%.