Assessment of POFA -Cementitious material as backfill barrier in DSRS borehole disposal: 226Ra confinement

Disused Sealed Radioactive Sources (DSRS) borehole disposal is an innovative concept recommended by international atomic energy agency (IAEA) to improve the safety and security of the management end point for these sources. A green application of Palm Oil Fuel Ash (POFA) as a supplementary material for cementitious backfill barrier in DSRS borehole disposal facility is proposed. Samples with up to 50% POFA replacement complied with the mechanical and hydraulic performance requirements for backfill barriers in retrievable radioactive waste disposal facilities. The structures of one year old OPC and optimum OPC-POFA cement backfills were evaluated using FESEM, XRD, EDXRF, BET, and TGA and their ²²⁶ Ra confinement performances were assessed. 30% POFA replacement improved the geochemical conditions by reducing competitive Ca²⁺ release into the disposal environment. It enhanced ²²⁶Ra confinement performance independently on the amount of water intrusion or releases below 2% of 1 Ci source. The improved performance is attributed to the higher fraction of active sites of OPC-POFA backfill compared to that of OPC backfill. ²²⁶Ra sorption onto C-S-H is irreversible, spontaneous, endothermic, and independent on the degree of the surface filling. The provided experimental data and theoretical analysis proved the feasibility of this green use of POFA in reducing the radiological hazard of ²²⁶Ra.

In vitro antidermatophytic activity and cytotoxicity of extracts derived from medicinal plants and marine algae

OBJECTIVES

This study was conducted to evaluate the antidermatophytic activity of 48 extracts obtained from medicinal plants (Cibotium barometz, Melastoma malabathricum, Meuhlenbeckia platyclada, Rhapis excelsa, Syzygium myrtifolium, Vernonia amygdalina) and marine algae (Caulerpa sertularioides, Kappaphycus alvarezii) against Trichophyton rubrum and Trichophyton interdigitale (ATCC reference strains), and the cytotoxicity using African monkey kidney epithelial (Vero) cells. Active plant extracts were screened for the presence of phytochemicals and tested against clinical isolates of Trichophyton tonsurans.

METHODS

Six different extracts (hexane, chloroform, ethyl acetate, ethanol, methanol and water) were obtained from each plant or algae sample using sequential solvent extraction. The antidermatophytic activity for the extracts was assessed using a colourimetric broth microdilution method. The viability of Vero cells was measured by Neutral Red uptake assay.

RESULTS

All the extracts (except the water extracts of V. amygdalina, C. sertularioides and K. alvarezii) showed antidermatophytic activity against Trichophyton spp. The minimum fungicidal concentration (MFC) ranges for the plant extracts against T. rubrum and T. interdigitale are 0.0025-2.50 and 0.005-2.50mg/mL, respectively. The algae extracts exhibited lower potency against both species, showing MFC ranges of 0.08-2.50 and 0.31-2.50mg/mL, respectively. The ethanol and methanol extracts from the leaves of R. excelsa, and the methanol and water extracts from the leaves of S. myrtifolium were highly active (MFC<0.1mg/mL) and with high selectivity indices (SI>2.8) against reference strains of T. rubrum and T. interdigitale, and most of the clinical isolates of T. tonsurans. Phytochemical analysis indicates the presence of alkaloids, anthraquinones, flavonoids, saponins, tannins, phenolics and triterpenoids in the extracts.

CONCLUSIONS

The medicinal plant extracts exhibited stronger antidermatophytic activity compared to the algae extracts. The leaves of R. excelsa and S. myrtifolium are potential sources of new antidermatophytic agents against Trichophyton spp.

Verification of MCNP simulation of neutron flux parameters at TRIGA MK II reactor of Malaysia

A 3-D model for 1 MW TRIGA Mark II research reactor was simulated. Neutron flux parameters were calculated using MCNP-4C code and were compared with experimental results obtained by k(0)-INAA and absolute method. The average values of φ(th),φ(epi), and φ(fast) by MCNP code were (2.19±0.03)×10(12) cm(-2)s(-1), (1.26±0.02)×10(11) cm(-2)s(-1) and (3.33±0.02)×10(10) cm(-2)s(-1), respectively. These average values were consistent with the experimental results obtained by k(0)-INAA. The findings show a good agreement between MCNP code results and experimental results.

Proteomic analysis of the molecular response of Raji cells to maslinic acid treatment

Maslinic acid, a natural pentacyclic triterpene has been shown to inhibit growth and induce apoptosis in some tumour cell lines. We studied the molecular response of Raji cells towards maslinic acid treatment. A proteomics approach was employed to identify the target proteins. Seventeen differentially expressed proteins including those involved in DNA replication, microtubule filament assembly, nucleo-cytoplasmic trafficking, cell signaling, energy metabolism and cytoskeletal organization were identified by MALDI TOF-TOF MS. The down-regulation of stathmin, Ran GTPase activating protein-1 (RanBP1), and microtubule associated protein RP/EB family member 1 (EB1) were confirmed by Western blotting. The study of the effect of maslinic acid on Raji cell cycle regulation showed that it induced a G1 cell cycle arrest. The differential proteomic changes in maslinic acid-treated Raji cells demonstrated that it also inhibited expression of dUTPase and stathmin which are known to induce early S and G2 cell cycle arrests. The mechanism of maslinic acid-induced cell cycle arrest may be mediated by inhibiting cyclin D1 expression and enhancing the levels of cell cycle-dependent kinase (CDK) inhibitor p21 protein. Maslinic acid suppressed nuclear factor-kappa B (NF-κB) activity which is known to stimulate expression of anti-apoptotic and cell cycle regulatory gene products. These results suggest that maslinic acid affects multiple signaling molecules and inhibits fundamental pathways regulating cell growth and survival in Raji cells.

Ministry of health clinical practice guidelines: cancer screening

The Ministry of Health publishes national clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with key recommendations from the guidelines) from the Ministry of Health clinical practice guidelines on cancer screening, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov. sg/mohcorp/publications.aspx?id=24018). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

p53 and bcl-2 expression in invasive and pre-invasive uterine papillary serous carcinoma and atrophic endometrium

INTRODUCTION

Uterine papillary serous carcinoma (UPSC), a high-grade tumour, is known to be associated in some cases with an identifiable intraepithelial neoplasia (IEN) component. Biomarker studies incorporating this latter component are not well documented. One aim of the present study was to compare levels of immunohistochemical (IHC) expression of p53 tumour suppressor gene and bcl-2 oncoprotein between UPSC and IEN, as well as normal endometrium to determine its biologic significance. The other major aim was to determine if these IHC results have any bearing on survival data in this tumour.

MATERIALS AND METHODS

An immunoreactivity score was assigned for examination of p53 and bcl-2 expression in a total of 21 cases of UPSC, 9 with an evaluable IEN component and 11 with associated non-neoplastic endometrium. Statistical analysis of IHC results was performed, in addition to correlation with survival data and disease stage.

RESULTS

p53 was identified in 16/21 cases of UPSC (76%) and 8/9 cases of IEN (89%), and no cases of normal endometrium. By contrast, bcl-2 was positive in all normal endometria with less expression in UPSC leaving 15/21 (71%) cases positive, and in IEN, leaving 5/9 (55%) of cases positive. Differences in immunoreactive scores for both p53 and bcl-2 between UPSC and benign glands, as well as between IEN and benign glands reached statistical significance with P values of 0.006 and 0.014 for p53, and 0.003 and 0.027 for bcl-2 respectively. There was no statistical significance between values for UPSC and IEN. Cox regression analysis found no statistically significant relationship between patient survival time in early and late stages of disease, and p53 and bcl-2 immunoscores.

CONCLUSIONS

The lack of a significant difference between the bcl-2 and p53 values for both UPSC and IEN suggests that these molecular alterations occur at an early stage of tumour pathogenesis. A potential advantage of the use of immunohistochemical markers is their application to routinely processed surgical specimens. In this case, bcl-2 and p53 were applied in UPSC to determine any potential significance, but neither marker proved to be a useful predictor of survival time or disease stage.

First-line gemcitabine versus epirubicin in postmenopausal women aged 60 or older with metastatic breast cancer: a multicenter, randomized, phase III study

BACKGROUND

This randomized, phase III study compared the efficacy and safety of first-line gemcitabine versus epirubicin in the treatment of postmenopausal women with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Patients aged > or = 60 years (median 68 years) with clinically measurable MBC received either gemcitabine 1200 mg/m(2) or epirubicin 35 mg/m(2) on days 1, 8, and 15 of a 28-day cycle.

RESULTS

Of 410 patients entered, 397 (198 gemcitabine and 199 epirubicin) were randomized and qualified for the time to progressive disease (TTP) and survival analyses. Total cycles administered in 185 gemcitabine and 192 epirubicin patients, respectively, were 699 (mean 3.5, range 0-12) and 917 (mean 4.6, range 0-10). Epirubicin demonstrated statistically significant superiority in TTP (6.1 and 3.4 months, P=0.0001), overall survival (19.1 and 11.8 months, P=0.0004), and independently assessed response rate (40.3% and 16.4% in 186 and 183 evaluable patients, P <0.001). For gemcitabine (n=190) and epirubicin (n=192), respectively, common WHO grade 3/4 toxicities were neutropenia (25.3% and 17.9%) and leukopenia (14.3% and 19.3%). Of the 28 on-study deaths (17 gemcitabine, 11 epirubicin), three were considered possibly or probably related to treatment (gemcitabine).

CONCLUSIONS

Postmenopausal women > or =60 years of age with MBC tolerate chemotherapy well. In this study, epirubicin was superior to gemcitabine in the treatment of MBC in women age > or =60, confirming that anthracyclines remain important drugs for first-line treatment of MBC.

Acceptance of prophylactic surgery and chemoprevention of cancer in Singapore - a survey

INTRODUCTION

In addition to surveillance practices, chemoprevention and prophylactic surgery can reduce the risk of cancer in individuals at high risk. Sociocultural factors may have a role to play in such decision making. Little is known regarding the factors that play a role in decision making in Singapore.

MATERIALS AND METHODS

One hundred and two individuals at normal risk completed a questionnaire on the concept of chemoprevention and prophylactic surgery. The results were analysed using the convenience sampling method.

RESULTS

Participants were mostly Chinese (94.1%). More than 90% of the respondents answered the section on prophylactic surgery and chemoprevention. Thirty-eight individuals (41.3%) would not consider prophylactic surgery, while 42 (45.7%) would not consider prophylactic surgery now but might consider it in the future. Twenty-five individuals (26.9%) would not consider chemoprevention by taking a medication, 57% would not consider it now but might in the future.

CONCLUSION

A cross-sectional public view suggests that medical prophylaxis is likely to be more acceptable to the general public compared to surgical prophylaxis.

Unusual case of bowel infarction with invasive Aspergillus in an immunocompromised patient

INTRODUCTION

We report a patient with bowel infarction due to invasive Aspergillus infection as a result of prolonged chemotherapy-induced neutropenia.

CLINICAL PICTURE

The patient was given neoadjuvant chemotherapy with doxorubicin, docetaxel, and capecitabine for a breast tumour. She developed prolonged neutropenia, Escherichia coli and Candida krusei sepsis, acute arterial thrombosis of the left lower limb, and invasive aspergillus infection.

TREATMENT

She underwent a subtotal colectomy, small intestine resection and an above-knee amputation.

OUTCOME

The hospitalisation was complicated with methicillin-resistant Staphylococcus aureus pneumonia and short gut syndrome. She subsequently underwent simple mastectomy with axillary clearance and received adjuvant chemotherapy and radiation without complication.

CONCLUSION

Chemotherapy should be protocol-directed. In a non-trial situation, protocol must have a sound basis, proven safety, and efficacy. Aspergillus infection is uncommon in patients with solid tumours; prompt treatment must be started on high suspicion.

Association between psychological symptoms in adults and growth in early life: longitudinal follow up study

OBJECTIVES

To test the hypothesis that birth weight for gestational age and weight gain in early childhood have a long term association with psychological distress in adults.

DESIGN

Longitudinal study of 1958 birth cohort followed to age 42 years.

SETTING

Population based birth cohort study.

PARTICIPANTS

9731 cohort members with valid perinatal, postnatal, and adult data.

MAIN OUTCOME MEASURES

Malaise inventory scores measured at ages 23, 33, and 42 years. Generalised estimating equations approach used to analyse repeated measures.

RESULTS

Psychological distress score was inversely related to birthweight z score and weight gain from birth to the age of 7 years. A unit increase in birthweight z score or childhood weight gain was associated with a mean reduction in psychological distress score of 0.10 (95% confidence interval 0.05 to 0.15) and 0.06 (0.02 to 0.10), respectively. Birth weight and weight gain were also inversely related to the odds of having a high level of psychological distress, with odds ratios being 0.90 (0.85 to 0.95) and 0.93 (0.89 to 0.98), respectively.

CONCLUSIONS

Psychological health in adults is related to fetal growth and growth in early childhood.

The need for collaboration between clinicians and statisticians: some experience and examples

INTRODUCTION

Very often we see poor communication and collaboration between clinicians and statisticians. Both sides may fail to realise the importance of a truly collaborative effort. In this paper we give examples to illustrate some problems clinicians and statisticians may encounter when they do not have the full support of each other. The aim is to convince both parties the importance of a truly collaborative effort.

METHODS

Real examples in various medical research areas are drawn from the authors' practical experience for illustration. The examples cover various research aspects such as the use of computer software, regression analysis and interpretation of findings.

RESULTS

Superficial collaboration between clinicians and statisticians may lead to serious problems and sub-optimal research practice that may not be obvious in the first sight. Some of the barriers to effective communication and collaboration are discussed.

CONCLUSIONS

On the one hand, robust statistical practice is vital in many medical research projects. On the other hand, medical thinking is important in the formulation and application of statistical strategies. Statistical inputs should be integrated into medical research projects throughout the whole research process. Sporadic contacts between clinicians and statisticians are not enough. Both parties must learn to communicate more effectively and to be willing to collaborate with each other.

Seasonal variation in breast cancer diagnosis in Singapore

This study investigates seasonality in the diagnosis of 3219 female breast carcinoma cases reported between 1995-8 in Singapore. There is little evidence of marked seasonal variation. Angular regression suggested that observed differences in peak diagnosis with respect to menopausal status, tumour size, ER and PR status may be chance.

Induction chemotherapy followed by concurrent chemoradiotherapy in stage III unresectable non-small cell lung cancer

The favourable experience with the combination regimen of vinorelbine, ifosfamide and cisplatin (NIP) in patients with metastatic non-small cell lung cancer (NSCLC) has led to a protocol assessing this regimen as an induction treatment in patients with stage III unresectable NSCLC, followed by thoracic radiotherapy with concurrent daily cisplatin as a radiosensitizer. Two cycles of NIP were administered 21 days apart; each cycle comprised i.v. vinorelbine 25 mg/m2 on days 1 and 8, i.v. ifosfamide 3 g/m2 on day 1 with MESNA as uroprotection, and i.v. cisplatin 50 mg/m2 on day 1. Radical thoracic radiotherapy commenced on day 43 to a total dose of 64 Gy and i.v. cisplatin 6 mg/m2 was given concurrently prior to each fraction of radiation as a sensitiser. Two more cycles of NIP were given to patients who responded favourably to the induction treatment about 2 weeks after completion of radiation. Between July 1995 and July 1997, 44 patients were treated with this protocol. This treatment schedule was generally well tolerated. Grade 3-4 neutropenia occurred in 50% of the patients and neutropenic sepsis was seen in 8. Grade 3-4 oesophagitis was uncommon. Most of the patients were able to complete the induction and concurrent chemoradiotherapy phase. Major response occurred in 75% of the patients with 2 (4.5%) complete responses (CR). A total of 6 patients achieved CR after chemoradiotherapy. At a median follow-up of 35 months, the median overall survival for all patients was 15 months with a 3-year survival rate of 24%. The median overall survival for stage IIIA patients was 19 months with a 3-year survival rate of 39% in contrast to 13 months' median overall survival and only 15% 3-year survival rate for stage IIIB. The NIP regimen results in a high response rate in NSCLC and this treatment programme seems to benefit selected patients with stage III disease.

Pseudomembranous colitis in a patient treated with paclitaxel for carcinoma of the breast: a case report

INTRODUCTION

The concomitant antimicrobial properties of antineoplastic agents may play a role in causing pseudomembranous colitis, which has been documented for cisplatin, cyclophosphamide and 5-fluorouracil.

CLINICAL PICTURE

We describe the first case reported in the English literature of severe pseudomembranous colitis occurring in a patient given paclitaxel as adjuvant chemotherapy for breast cancer. There was no prior antibiotic therapy. Stool culture confirmed Clostridium difficile.

TREATMENT

Oral vancomycin, metronidazole and cholestyramine led to prompt improvement of intestinal symptoms, which resolved in two weeks.

OUTCOME

Repeat colonoscopy performed 3 months later showed total resolution of the colitis.

CONCLUSIONS

Awareness of pseudomembranous colitis after paclitaxel chemotherapy can avert life-threatening complications.

Vinorelbine, ifosfamide and cisplatin in advanced non-small cell lung cancer

Between September 1994 and July 1997, 78 patients with advanced/metastatic, non-small cell lung cancer (NSCLC) were selected for the NIP (vinorelbine, ifosfamide, and cisplatin) protocol. The study group included 43 males; age range 34-74 years; median age 56 years; median follow-up for all patients was 14 months and for surviving patients, 30 months. Histological distribution included 55 adenocarcinomas (70.5%), 8 squamous cell carcinomas, and 9 large cell carcinomas. Stage distribution was 14 stage IIIB (malignant effusions) and 64 stage IV or recurrent metastatic; sites of metastasis were lungs, -26; liver-19; bones-27; brain-7; adrenals-3; distant nodes-2; skin-2. The NIP regimen was well tolerated by most of the patients but nausea/vomiting was noted in 55% of the cycles administered, most of them of grade 1-2 severity. Fifteen neutropenic episodes (5%) were encountered. Response to NIP was: 44 partial responses (56%); 1 complete response (1%); overall response, 58%. For stage IIIB, overall response was 36%, while for stage IV/metastatic, overall response was 63%. The median time to progression was 7 months for stage IIIB and 8 months for stage IV/metastatic disease and the overall median survival achieved was 14 months, with 60% of patients alive after one year. No significant difference in survival outcome was noted between patients with metastatic disease and those with stage IIIB (malignant effusion) disease. The NIP regimen has produced encouraging results in advanced NSCLC, as well as a favourable toxicity profile. The efficacy of NIP as a palliative tool should be assessed. A randomized trial to compare NIP with a two-drug combination of vinorelbine and cisplatin has been initiated.

Salivary proteins in rheumatoid arthritis and Sjögren's syndrome: one-dimensional and two-dimensional electrophoretic studies

Parotid saliva from patients with rheumatoid arthritis and Sjögren's syndrome contains elevated levels of multiple anionic proteins of pI approximately 3.75-4.75 and Mr approximately 32,000. Further studies on these components involving narrow range pH 3.5-5.0 immobilized pH gradients (IPGs) and two-dimensional (2D) electrophoresis with narrow- or broad-range IPGs in the first dimension have confirmed their association with these disorders. Immunoblotting showed that these proteins include multiple forms of tissue kallikrein. Treatment with neuraminidase results in removal of these anionic substances from the pH 3.75-4.75 region of gels, thereby indicating that heterogeneity arises from differences in sialation of the carbohydrate residues. The results of treatment with endo-beta-N-acetylglucosaminidase (Endo F) or peptide N-glycosidase (PNGase F) and comparison of the results with studies on human urinary kallikrein suggest that proteins other than kallikrein may also comigrate in the anionic region of gels and that deglycosylation of kallikrien is incomplete in the experimental conditions used, probably because of inadequate denaturation. The paper also reviews the limitations of current criteria used in the investigation of salivary gland function associated with connective tissue disorders and the diagnosis of these. It assesses the potential of electrophoresis in forming the basis of new diagnostic techniques and furthering the understanding of the nature of these diseases. The findings presented in this paper could make a key contribution to this.

Continuous infusion 5-fluorouracil as salvage chemotherapy in patients with advanced colorectal cancer

For almost 40 years, 5-fluorouracil (5-FU) has been the only useful drug with clinically meaningful activity in metastatic colorectal carcinoma. When the disease progresses or recurs despite bolus 5-FU treatment, the options are limited. Our study shows that 5-FU given by continuous infusion is a viable alternative. Fifty-three patients received continuous infusion 5-FU. The overall response was 9%. Median survival of the entire cohort was 5 months. Patients with partial response and stable disease had median survival duration of 8 and 9 months, respectively. A dose-response relationship was observed. The commonest toxicities were mucositis (34%) and palmar-plantar syndrome (24%). There was no central line-related complication. Continuous infusion 5-FU is an effective "second-line" treatment. Further work is needed to ascertain its role, in comparison with newer agents like irinotecan (CPT-11), and oxaliplatin.

Phase II trial of a paclitaxel and carboplatin combination in Asian patients with metastatic nasopharyngeal carcinoma

PURPOSE

An earlier phase II trial of paclitaxel in patients with metastatic nasopharyngeal carcinoma (NPC) demonstrated a response rate of 22%. Hence we proceeded to study the combination of paclitaxel and carboplatin in these patients.

PATIENTS AND METHODS

The 21-day regimen was as follows: i.v. paclitaxel 175 mg/m2 over three hours preceded by standard premedications, followed by i.v. carboplatin dosed at AUC of six infused over one hour. Only chemotherapy-naive patients with histological diagnoses of undifferentiated carcinoma of the nasopharynx, systemic metastases and radiologically measurable lesions were eligible.

RESULTS

Thirty-two patients were accrued to this study. Twenty patients (62%) had at least two sites of metastasis. The main grade 3-4 toxicity was neutropenia (31%). Nine patients (28%) developed neutropenic sepsis, which caused the demise of one of them. Twenty-four patients (75%) responded to treatment, with one (3%) attaining a complete response. The median time to progression of disease was seven months and the median survival was 12 months. At one year, 52% of the patients were alive.

CONCLUSIONS

The combination of paclitaxel and carboplatin is an active regimen in NPC. Its convenience of administration and good tolerability make it an attractive alternative regimen to consider for patients with metastatic disease.

Specific retinoid receptors cooperate to signal growth suppression and maturation of human embryonal carcinoma cells

This study addresses the contributions of specific retinoid receptors during all-trans-retinoic acid (RA)-mediated differentiation and growth suppression of human embryonal carcinoma cells. The pleiotropic effects of RA are mediated by retinoic acid receptors (RARs) and retinoid X receptors (RXRs), members of the nuclear receptor family of transcription factors. After RA-treatment the multipotent human embryonal carcinoma cell line NTERA-2 clone D1 (NT2/D1) displays limited proliferative potential, reduced tumorigenicity, and morphologic and immunophenotypic neuronal maturation. RARgamma over-expression in NT2/D1 cells signals mesenchymal NT2/D1 terminal differentiation while RARalpha and RARbeta do not and RARgamma overcomes retinoid resistance in an NT2/D1 clone (NT2/D1-RI) having deregulated RARgamma expression. Since RARgamma transfectants do not display neuronal maturation, this study sought to identify cooperating retinoid receptors engaged in NT2/D1 differentiation. Through gain of function experiments, this report highlights RXRbeta as playing an important role along with RARgamma in signaling differentiation of NT2/D1 cells. Stable over-expression of RXRbeta, but not RXRalpha or RXRgamma, was found to signal NT2/D1 growth suppression and to induce a non-neuronal morphology and immunophenotype. Notably, co-transfection of RARgamma and RXRbeta resulted in marked growth suppression and for the first time, expression of typical neuronal markers of NT2/D1 differentiation. To clarify the role of RXRbeta and RARgamma in this differentiation program, a modified transient fibroblast growth factor-4 (FGF4) promoter-enhancer reporter assay that reflects effective RA-mediated differentiation of NT2/D1 cells was employed. Transfection of RARgamma or RXRbeta in NT2/D1 cells augments transcriptional repression of the FGF4 reporter and RARgamma and RXRbeta co-transfection markedly repressed reporter activity, indicating the combined role of these receptors in RA-induced NT2/D1 differentiation. Taken together, these findings reveal specific retinoid receptors must cooperate to signal terminal growth suppression and maturation of NT2/D1 cells. Since the transcriptional repression of FGF4 is coupled to the effective maturation of human embryonal carcinoma cells, the described co-transfection strategy should prove useful to identify genes with positive or negative effects on the differentiation program of these tumor cells.

Derivation and characterization of retinoid-resistant human embryonal carcinoma cells

The retinoids exert potent growth and differentiation effects on normal and neoplastic cells through two families of nuclear receptors. These are the retinoic acid receptors (RAR alpha, RAR beta, RAR gamma) and the retinoid-X receptors (RXR alpha, RXR beta, RXR gamma). All-trans retinoic acid (RA) induces terminal neuronal differentiation and represses tumorigenicity of the multipotent human embryonal carcinoma cell line NTERA-2 clone D1 (NT2/D1). Hexamethylene bisacetamide (HMBA) induces a phenotype distinct from RA-treated NT2/D1 cells. This study reports the derivation and characterization of RA- and HMBA-resistant NT2/D1 clones. Nine RA-resistant (NT2/D1-R1 through NT2/D1-R9) and one HMBA-resistant (NT2/D1-H1) clones were derived after mutagen treatment of NT2/D1 cells and selection in RA or HMBA. NT2/D1-R cells were cross-resistant to 9-cis retinoic acid (9-cis RA), a ligand activating the RAR and RXR pathways, but retained maturation response to HMBA. A representative RA-resistant clone, NT2/D1-R1, overcame the antitumorigenic actions of RA as assessed in athymic mice. NT2/D1-H1 cells were dually resistant to RA and 9-cis RA. All these retinoid resistant cells exhibit deregulated expression of RAR gamma but not RAR alpha or RAR beta. Southern analysis using RAR gamma probes shows no apparent structural differences in genomic DNA between NT2/D1 cells and the RA-resistant subclones. Pulsed-field gel electrophoresis (PFGE) with RAR gamma probes demonstrated an Mlu-I restriction fragment length polymorphism, but no other structural abnormalities in these cells or a panel of germ cell tumor (GCT) cell lines. Full-length RAR gamma 1 coding region cDNAs were cloned from NT2/D1 and NT2/D1-R1 cells and these sequences were identical, suggesting RA resistance in these cells is due to altered regulation of RAR gamma. These differentiation-resistant cells are useful to study RAR gamma target genes or mechanisms engaged by these differentiation inducing agents in human embryonal carcinomas.

all-trans retinoic acid for treating germ cell tumors. In vitro activity and results of a phase II trial

BACKGROUND

Germ cell tumors (GCTs) are characterized by a capacity to differentiate in vivo and in vitro. The authors' previous work highlighted the finding that retinoid-mediated GCT differentiation in vitro correlates with expression of the retinoic acid receptor-gamma.

METHODS

Six human GCT cell lines were studied to determine whether their growth and differentiation were linked to the retinoic acid response pathway. The maturation and growth inhibitory responses to all-trans retinoic acid (RA) were studied as well as the expression of retinoic acid receptor-gamma (RAR-gamma). The clinical antitumor activity of RA was studied in a Phase II trial of RA in patients with chemotherapy-refractory GCTs.

RESULTS

The RA response pathway was correlated with the control of growth and maturation in three of the six GCT cell lines studied. In one GCT cell line, RA induced RAR-gamma expression and terminal differentiation. In a second, there was high basal expression of RAR-gamma and poor basal proliferative potential. A third cell line showed a more mature basal phenotype than other cell lines studied and marked growth inhibition when treated with RA. Sixteen patients were treated with RA for an average of 7 weeks in the clinical trial. No complete or partial responses were noted.

CONCLUSION

A Phase II clinical trial of RA failed to show significant clinical antitumor activity in patients with chemotherapy-refractory GCTs. However in vitro data suggest that the control of growth and maturation in some GCT cell lines involve the RA signaling pathway. Further studies are warranted to define the role that other retinoids with receptor selectivity or more favorable pharmacologic properties may play in the maturation or antitumor responses of GCTs.

Extract of astragalus membranaceus and ligustrum lucidum does not prevent cyclophosphamide-induced myelosuppression

There is increasing evidence that many Chinese medicinal herbs are promising biological response modifiers in cancer treatment. The extract of some Chinese herbs have shown ability in stimulating the bone marrow and improving the peripheral white cell counts in rats. We studied the effect of a dried extract of two commonly used Chinese herbs, Astragalus membranaceus (AM) and Ligustrum lucidum (LL) on cytotoxic-induced myelosuppression. Wistar rats weighing 250-300g each were divided into two groups of 12. Both groups were given cyclophosphamide intravenously at 75 mg/kg on day 1 of the study. Rats in the study group were fed 240 mg of crude extract of AM and LL from day 1 to day 12 of study. The daily absolute neutrophil count (ANC) and the platelet count were monitored. There was no difference between the study and the control group in terms of nadir count, time to nadir and time to recovery for both the ANC and the platelet counts. The duration of neutropenia (ANC < 1.0 x 10(9)/L) was also similar in both groups. Our results showed that the extract of AM and LL does not prevent cyclophosphamide-induced myelosuppression.

Control of emesis by intravenous granisetron in breast cancer patients treated with 5-FU, epirubicin and cyclophosphamide

Granisetron, a potent and selective 5-hydroxytryptamine receptor (5-HT3) antagonist was reported to be an effective antiemetic agent both in animal studies and in patients given highly emetogenic chemotherapy. A sample of 43 patients with breast cancer was accrued from September to November 1992 in a phase II study to assess the efficacy of granisetron in patients receiving FEC (5-FU, epirubicin, cyclophosphamide). Each patient received 3 mg intravenous granisetron as a single dose just prior to chemotherapy. Oral metoclopromide was prescribed to each patient as a rescue anti-emetic. The emetic episodes and degree of nausea were evaluated on a daily basis. Good control of emesis (0-2 episodes of vomiting) and nausea (mild or no nausea) was in the range 77%-98% and 77%-93% respectively. There was a complete response (no emetic episodes throughout the 6-day period) in 16 patients (37.2%). Onset of emesis tends to occur on day 1 and tend to subside after day 3; 85% of patients had onset of emesis in the first 2 days after chemotherapy. Control of emesis and nausea tends to improve after day 3, which could be the result of the reduced emetogenicity of the combination FEC with time. Altogether, 77% had good control of acute emesis; control of delayed emesis was better with 84% achieving a major response on day 2 after chemotherapy, which improved to more than 90% after day 4. Granisetron was generally tolerated with headache being the most common side-effect followed by constipation and flushing. This study suggests that granisetron is an effective and well-tolerated anti-emetic agent, which deserves randomised trials to elucidate its efficacy further.

Purification and partial characterization of two cytolysins from a tropical sea anemone, Heteractis magnifica

Two cytolysins, designated as magnificalysins I and II, were purified from a tropical sea anemone, Heteractis magnifica (formerly Radianthus ritteri). The purification steps involved Sephadex G-50 and CM-Sepharose chromatography followed by Mono S and Phenyl-Superose Fast Protein Liquid Chromatography. The relative mol. wt of magnificalysins I and II, determined by SDS-PAGE, was approximately 19,000, while their isoelectric points, determined by isoelectric focusing in immobilized pH gradients, were 9.4 and 10.0, respectively. Those toxins were found to have haemolytic and lethal activities. The haemolytic activities of magnificalysins I and II were 3.6 x 10(4) HU/mg and 3.3 x 10(4) HU/mg, while their LD50 (i.v., mice) values were approximately 0.14 microgram/g and 0.32 microgram/g, respectively. The amino acid composition and N-terminal sequences of magnificalysins I and II were also obtained. They do not possess any cysteine or cystine residue, but are rich in basic and hydrophobic amino acids. The N-terminal amino acid sequences of magnificalysins I and II are ALAGTIIAGASLTFKILDEV and SAALAGTIIDGASLGFDILNKV, respectively. These are highly homologous to cytolysins from other sea anemones, particularly cytolysin III from Stichodactyla helianthus, a Caribbean anemone.

Use of oral and intravenous ondansetron in patients treated with cisplatin

Ondansetron, a selective 5-HT3 antagonist, has been shown to be effective in preventing chemotherapy-induced nausea and vomiting. From July and August 1991, 25 patients were accrued in a phase II study to assess the efficacy of ondansetron in patients receiving cisplatin-containing chemotherapy. Patients received intravenous cisplatin 100 mg/m2, given either as a 24-hour infusion on day 1 or in divided doses as eight-hour infusions daily on days 1 to 3. Each patient received 24 mg of ondansetron per day for six days. Intravenous dexamethasone 24 mg was given daily on the days of cisplatin infusion. The emetic episodes and degree of nausea were evaluated daily. "Good" control of emesis (0-2 episodes of vomiting) and nausea (mild or no nausea) ranged from 64-100% and 88-100% respectively. Failure in emesis control occurred most frequently on days 3 and 4. Ondansetron was generally well tolerated with only minimal side-effects. One patient developed unexplained encephalopathy which resolved completely. Our results suggest that ondansetron is an effective anti-emetic agent with minimal toxicities. Randomised studies comparing ondansetron against "standard" anti-emetics should be conducted.

Common toxicities of cancer chemotherapy

Sixty cancer patients who were receiving chemotherapy at an outpatient Oncology Centre were surveyed for their views on a list of treatment-related toxicities. The severity of each toxicity was assessed using a visual analogue scale. Sixty percent of patients felt that the overall toxicity was acceptable. Ten percent felt like giving up. Problem with venous access was named the worst toxicity by 37% of patients, followed by nausea and vomiting (19%), and long waiting time (11%). Male patients tended to tolerate chemotherapy better. The female patients were significantly more affected by hair loss than their male counterpart. Better understanding of the toxicities of chemotherapy as perceived by the patients themselves allows them to take appropriate measures in improving their quality of life.

Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of human parotid salivary proteins

The proteins in human parotid saliva have been separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis into 20 or more well resolved species. The Coomassie Brilliant Blue (CBB) R-250 and silver staining procedures have been modified to overcome the problems encountered with staining of proline-rich proteins. By means of the CBB R-250 procedure which stains proline-rich proteins pink-violet, immunoblotting, concanavalin A binding, periodate-Schiff staining and zinc binding, all of the major proteins have been characterised. Substantial individual-to-individual differences were observed in the protein patterns formed. Comparison of parotid, submandibular, and whole saliva from a single individual indicated that fewer proline-rich proteins are expressed in submandibular saliva than in parotid, but whole saliva contains much lower levels than either duct secretion. The results will form a useful base for future research into the functions of salivary proteins.

Two-dimensional electrophoresis of human parotid salivary proteins from normal and connective tissue disorder subjects using immobilised pH gradients

Two-dimensional electrophoretic analysis of human salivary proteins using immobilised pH gradients in the first dimension, thin-layer gradient horizontal sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the second, and modified staining procedures has resulted in a substantial improvement in their resolution. Unlike carrier ampholyte-based techniques, immobilised pH gradients prevent the loss of proteins of pI greater than 8; accordingly, basic components, including basic proline-rich proteins, can now be resolved. A two-dimensional map showing the locations and identities of most of the major proteins has been constructed. Narrow-range pH gradients can be constructed to give increased resolution of proteins of particular interest. By means of a pH 3.5-5.0 gradient, the abnormal salivary proteins associated with connective tissue disorders were found to be a highly heterogeneous group of pI approximately 3.75-4.75 and Mr approximately 32,000; although low levels occurred in some normal individuals, there was less heterogeneity (pI approximately 3.75-4.25). The technique should form a base for future structural, functional, and clinical studies on human salivary proteins.

Isoelectric focusing of human parotid salivary proteins in hybrid carrier ampholyte-immobilized pH gradient polyacrylamide gels

Isoelectric focusing of human salivary proteins with carrier ampholyte-isoelectric focusing systems requires prior desalting and concentration of samples, a procedure which is time-consuming and requires relatively large volumes of samples. By contrast, immobilized pH gradient gels are more tolerant to salt loads. Thus pretreatment of samples consists only of centrifugation prior to isoelectric focusing. If larger loads (greater than 50 micrograms) are required, the samples may be concentrated by lyophilization and reconstitution in a smaller volume of water or by dialysis against 30% w/v polyethylene glycol. Immobilized pH gradient polyacrylamide gels (incorporating a hybrid carrier ampholyte system) of two pH ranges (pH 4-9 and pH 3.5-5.0) have been used to separate the proteins in human parotid saliva. The effects of urea on focused patterns were studied; in pH 4-9 gels it gave improved resolution of protein bands, whereas in pH 3.5-5.0 gels it prevented protein precipitation. The salivary proteins were then visualized by staining with Coomassie Brilliant Blue G-250 or a silver procedure. Using the latter, 25-30 well-resolved bands were formed on a pH 4-9 gel loaded with 20 micrograms of proteins. The method offers considerable advantages compared with carrier ampholyte-isoelectric focusing.