Enhancement of cisplatin sensitivity of cisplatin-resistant human cervical carcinoma cells by bryostatin 1.

PURPOSE: Bryostatin 1, a unique protein kinase C (PKC) activator, is already in the clinical trials. An understanding of complex regulation of PKC by bryostatin 1 is essential for effective use of bryostatin 1 in the clinic. We have previously shown that the ability of bryostatin 1 to enhance cisplatin sensitivity correlated with its ability to down-regulate PKCdelta in HeLa cells. We have investigated how bryostatin 1 influences PKCdelta regulation in cisplatin-resistant HeLa (HeLa/CP) cells, and if bryostatin 1 could be used to reverse cisplatin resistance. EXPERIMENTAL DESIGN: Phorbol 12,13-dibutyrate (PDBu), bryostatin 1, and small interfering RNA were used to manipulate PKC level/activation status. Cell death was monitored by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Annexin V dye-binding assay, and analysis of hypodiploid peak in a flow cytometer. RESULTS: Bryostatin 1 elicited a biphasic concentration response on PKCdelta down-regulation and cisplatin-induced cell death in HeLa/CP cells; the maximum effect was achieved with 1 nmol/L bryostatin 1. Down-regulation of PKCalpha increased with increasing concentrations of bryostatin 1. PDBu induced down-regulation of PKCalpha in HeLa and HeLa/CP cells but it had little effect on PKCdelta down-regulation in HeLa/CP cells. However, both PDBu and bryostatin 1 enhanced the sensitivity of HeLa/CP cells to cisplatin. Knockdown of PKCdelta by small interfering RNA inhibited cisplatin-induced apoptosis but knockdown of PKCalpha enhanced cisplatin-induced cell death. CONCLUSIONS: These results suggest that although PKCdelta acts as a proapoptotic protein, full-length PKCdelta may inhibit cisplatin-induced cell death. Thus, persistent activation/down-regulation of PKCdelta by bryostatin 1 was associated with cisplatin sensitization. Furthermore, PKCalpha acts as an antiapoptotic protein and down-regulation of PKCalpha by PDBu was associated with cellular sensitization to cisplatin.     

A hernia in the inguinal region is not always an inguinal hernia

A male patient of 60 years presented with a swelling in the left groin of 10 months duration. Past records showed bilateral lumbar sympathectomy and omentopexy done 20 and 6 years back, respectively, for Buerger’s disease. Abdominal examination revealed a huge hernial swelling in the left groin extending from the symphysis pubis to anterior superior iliac spine measuring 25 × 18 cm. On exploration, the contents were intestines and omentum, which were coming out through a defect of 5 × 3 cm in the lower fibers of the conjoint muscle 4 cm cephalad to the deep ring, a finding which made the final diagnosis as an incisional hernia. We present this interesting case as a very rare complication of omentopexy, probably not reported previously, and an unusual case of an incisional hernia presenting as an inguinal hernia which is very difficult to diagnose unless encountered before. Its rarity and clinical challenge is highlighted.     

Cystic fibrosis presenting with bilateral facial palsy.

A 15-week old male infant presented with bilateral lower motor neuron facial palsy of unknown cause. Subsequently his growth deteriorated and he developed progressively worsening cough and wheeze. A diagnosis of cystic fibrosis was confirmed and hypovitaminosis A detected. Improvement of the facial palsy was noted following standard management of cystic fibrosis including vitamin A supplementation.     

Ultrastructural changes of the rabbit corneal epithelium and endothelium after Timoptic treatment

The purpose of this study was to determine whether timolol maleate (Timoptic) is cytotoxic to the cornea. The drug was applied as topical drops for 1 month to control rabbit eyes and rabbit eyes from which the epithelium had been removed or to de-epithelialized full-thickness autografts. Clinically all corneas and grafts remained clear. Scanning and transmission electronmicroscopy however revealed is drug induced epithelial damage, defective epithelial wound healing, and endothelial changes. The endothelial changes were most prominent in the group of rabbits that underwent de-epithelialization before corneal grafting.     

Injury to rat hearts produced by an exogenous free radical generating system. Study into the role of arachidonic acid and eicosanoids

This study was designed to evaluate the effect of an exogenous free radical generating system consisting of purine plus xanthine oxidase on the isolated rat heart and in particular to assess the possible contribution of arachidonic acid or its metabolites to toxicity produced by this drug combination. Purine plus xanthine oxidase produced a time-dependent depression in cardiac contractility which was associated with stimulated release of lactate dehydrogenase (LDH). Electron microscopic analysis revealed a distinct separation of the glycocalyx from the sarcolemmal membrane with no apparent intracellular defects. Purine plus xanthine oxidase was a potent stimulus for 6-keto-prostaglandin F1 alpha (6K-PGF1 alpha) synthesis but leukotriene production was undetectable under any condition. Eicosatetraynoic acid, which totally prevents the metabolism of arachidonic acid, accelerated the loss in force and increased LDH release invoked by purine plus xanthine oxidase, but produced no noticeable change in sarcolemmal ultrastructure. Cyclooxygenase inhibitors produced little influence although pretreatment with either acetylsalicylic acid or ibuprofen decreased contractility toward the end of purine plus xanthine oxidase perfusion. Nordihydroguarietic acid, a purported inhibitor of 5'-lipoxygenase accelerated the loss in force produced by purine plus xanthine oxidase. The nordihydroguarietic acid effects were associated with reduced 6K-PGF1 alpha efflux but LDH release was unaffected. We also examined whether modification of arachidonic acid release through changes in calcium concentration was associated with altered response to purine plus xanthine oxidase. Lowering the calcium concentration to 0.41 mM (from 1.25 mM control) reduced markedly 6K-PGF1 alpha, efflux as well as LDH release. Although the latter is suggestive of protection, hypocalcemic perfusion resulted in a greater loss in force due to free radical generation. Furthermore, cells from these hearts exhibited a greater degree of glycocalyx separation. Increasing the calcium concentration to 2.50 mM produced no further toxic manifestations in the response to purine plus xanthine oxidase, although the release of 6K-PGF1 alpha was increased. Our results suggest complex toxicity induced by an exogenously generated free radical system. The injury produced by this method is restricted to sarcolemmal changes, the latter being dependent on the external calcium concentration. The study further suggests that accumulation of intracellular unesterified arachidonic acid, which may result from peroxidation of membrane lipids, increases tissue injury caused by exogenous free radicals.     

Donor eyes. A comparison of characteristics and outcomes for Eye Bank and local tissue

The Corneal Recipient Registry was begun in 1985 to collect information on all recipients of corneal grafts in the province of Ontario, Canada, and on the donors providing tissue. While most of the tissue is handled by the Eye Bank of Canada (Ontario Division), ophthalmologists in centers away from the Eye Bank often use local tissue when it is available. Comparison of the donor characteristics of local tissue with that obtained through the Eye Bank revealed that local donors were 9-10 years younger (p less than 0.01), their times to enucleation were an hour less (p less than 0.02), and they were much more likely to be the victims of trauma than the donors of Eye Bank eyes. Prognosis of the graft, assessed using life table methods, suggested that success of local eyes was 89% after 6 months, compared with 80% for Eye Bank eyes in the same period, but this was not a significant difference (p greater than 0.05). While the Eye Bank is a more common source of tissue, eyes obtained locally are more likely to represent the "ideal" tissue for many corneal surgeons.     

Intestinal neuronal disorders--a study of seven cases

Intestinal neuronal dysplasia (IND) has been reported as an innervation disorder that can present as isolated disease or may be associated with Hirschsprung's disease (HD). The interest in this disorder is growing as it mimics HD at clinical level but can be managed with a more conservative approach if an accurate diagnosis can be made. Many workers have tried to set up diagnostic criteria of this condition. But the importance of one criterion varied from one study to another. In our study we analysed seven cases of suspected innervation disorder that had undergone resection. A detailed histological study on these cases was performed and four of them were found to fulfill the diagnostic criteria of IND laid down by Kobayashi and his co-workers. These patients had hyperganglionosis, giant ganglia and ectopic ganglion cells in the lamina propria. In the other three cases some features were highly suggestive of the diagnosis of the IND and can be considered to be so if we follow other workers who have not given much importance to the simultaneous presence of all three criteria in a single case.     

Abuse of neuroleptic drug by psychiatric patients

Due to the depaminergic neurotrasmission in the mesocortical and mesolimbic reward systems, the neuroleptic drugs have been considered free from the risk of abuse or dependence because of their antidopaminergic properties. Here, two cases of neuroleptic abuse have been described and a possibility of reward circuits other than mesocortical and mesolimbic systems operational behind this phenomenon has been postulated. There is a need to clinically recognise the abuse potential of neuroleptic drugs.