Morphodensitometric analysis of protein kinase C beta(II) expression in rat colon: modulation by diet and relation to in situ cell proliferation and apoptosis

We have recently demonstrated that overexpression of PKC beta(II) renders transgenic mice more susceptible to carcinogen-induced colonic hyperproliferation and aberrant crypt foci formation. In order to further investigate the ability of PKC beta(II) to modulate colonocyte cytokinetics, we determined the localization of PKC beta(II) with respect to cell proliferation and apoptosis along the entire colonic crypt axis following carcinogen and diet manipulation. Rats were provided diets containing either corn oil [containing n-6 polyunsaturated fatty acids (PUFA)] or fish oil (containing n-3 PUFA), cellulose (non-fermentable fiber) or pectin (fermentable fiber) and injected with azoxymethane (AOM) or saline. After 16 weeks, an intermediate time point when no macroscopic tumors are detected, colonic sections were utilized for immunohistochemical image analysis and immunoblotting. Cell proliferation was measured by incorporation of bromodeoxyuridine into DNA and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling. In the distal colon, PKC beta(II) staining was localized to the upper portion of the crypt. In comparison, proximal crypts had more (P < 0.05) staining in the lower tertile. AOM enhanced (P < 0.05) PKC beta(II) expression in all regions of the distal colonic crypt (upper, middle and lower tertiles). There was also an interaction (P < 0.05) between dietary fat and fiber on PKC beta(II) expression (corn/pectin > fish/cellulose, fish/pectin > corn/cellulose) in all regions of the distal colonic crypt. With respect to colonic cell kinetics, proliferation paralleled the increase in PKC beta(II) expression in carcinogen-treated animals. In contrast, apoptosis at the lumenal surface was inversely proportional to PKC beta(II) expression in the upper tertile. These results suggest that an elevation in PKC beta(II) expression along the crypt axis in the distal colon is linked to enhancement of cell proliferation and suppression of apoptosis, predictive intermediate biomarkers of tumor development. Therefore, select dietary factors may confer protection against colon carcinogenesis in part by blocking carcinogen-induced PKC beta(II) expression.     

Randomized trial of paclitaxel plus supportive care versus supportive care for patients with advanced non-small-cell lung cancer

BACKGROUND: In phase II trials, paclitaxel has been shown to have antitumor activity in patients with advanced non-small-cell lung cancer (NSCLC). However, the survival and quality-of-life (QOL) benefits of paclitaxel used as a single agent compared with supportive care alone have not been assessed in a randomized clinical trial. METHODS: A total of 157 patients with stage IIIB or IV NSCLC who had received no prior chemotherapy were randomly assigned to receive either best supportive care alone (78 patients) or paclitaxel plus supportive care (79 patients). Paclitaxel was administered as a 3-hour intravenous infusion every 3 weeks. Supportive care included palliative radiotherapy and supportive therapy with corticosteroids, antibiotics, analgesics, antiemetics, transfusions, and other symptomatic therapy as required. The primary end point of the study was survival. Time to disease progression, response rate, adverse events, and QOL were secondary end points. RESULTS: Pretreatment characteristics were evenly distributed between the two arms. Survival was statistically significantly better in the paclitaxel plus supportive care arm than in the supportive care alone arm (two-sided P =.037) (median survival = 6.8 months versus 4.8 months). Cox multivariate analysis showed paclitaxel plus supportive care to be statistically significantly associated with improved survival (two-sided P =.048). QOL was similar for both treatment arms, except for the functional activity score of the Rotterdam Symptom Checklist, where QOL data statistically significantly favored the paclitaxel plus supportive care arm (two-sided P =.043). CONCLUSION: The addition of paclitaxel to best supportive care significantly improved survival and time to disease progression compared with best supportive care in patients with advanced NSCLC and may improve some aspects of QOL.     

Open label, multi-centre phase II study of raltitrexed (`Tomudex') in patients with inoperable squamous-cell carcinoma of head and neck

Background:Raltitrexed (`Tomudex') is a folate based inhibitorof thymidylate synthase which has been registered in Europe and Australia forthe treatment of advanced colorectal cancer. In a European phase I trial ofraltitrexed anti-tumour activity was seen in two patients with head and neckcancer, prompting the current study. Patients and methods:From November 1996 to December 1998, 24patients with metastatic or recurrent squamous-cell carcinoma of the head andneck from 7 Australian centres received raltitrexed, 3 mg/m² givenintravenously over 15 minutes every 3 weeks, for a maximum of 6 cycles.Patients were required to be chemotherapy naïve and have measurabledisease, age >18 years, WHO performance status initially 2, nosignificant intercurrent illness or organ dysfunction and a life expectancy>12 weeks. Results:Twenty-two men and two women, median age 65 years, medianperformance status 1 were enrolled. Fifteen patients (63%) had receivedboth prior surgery and radiotherapy. In 15 patients (63%) there wasrecurrent locoregional disease only. Twelve patients (50%) received onecycle of treatment with only four patients (17%) receiving four or morecycles of treatment. No patient achieved a complete or partial response,although 5 patients experienced stable disease which lasted a median of 188days (range 61–436). The median survival for the whole group was 101days (range 20–436). Raltitrexed was generally well tolerated withminimal anti-proliferative toxicity. Conclusions:Single-agent raltitrexed does not demonstratesignificant anti-tumour response rates in patients with predominantly locallyrecurrent head and neck cancer.     

Early operable breast cancer

Opinion statement Early operable breast cancer is a potentially curable disease. However, a substantial number of patients are at risk for systemic recurrence and death. Breast conservation therapy (BCT) should be considered the preferred surgical option for most women with early operable breast cancer. Adjuvant systemic chemotherapy or hormonal therapy can substantially reduce, although not eliminate, the risk of recurrence and death. Neoadjuvant or primary systemic therapy (PST) in operable breast cancer slightly increases the number of women treated with breast conservation versus mastectomy. Although PST may identify women who are likely to have a better prognosis (those with a pathologic complete response), current PST strategies do not offer a survival advantage over standard adjuvant approaches. Early results of high-dose chemotherapy trials thus far have not shown any advantage over conventional dose therapy in high-risk patients with 10 or more positive lymph nodes. The role of adjuvant radiation therapy after mastectomy for all patients with high-risk early operable breast cancer is not fully defined.     

Assessment of a strategy for the control of respiratory diseases in children.

A programme for the control of respiratory diseases in children was conceived for the State of S. Paulo, Brazil, in 1986. Its progress thereafter and the epidemiology of the diseases concerned are examined. Apart from an inquiry into the 64 existing State local health authorities, a sample of 18,255 cases of children assisted by the programme at different levels, including both in-patient and outpatient care, is analysed. Each case record included information about identification (child, doctor and health facility), reasons for calling, diagnoses made and outcome of treatment. Further data were also sought from hospitals and from State mortality records. The programme was found to be poorly implemented in the State but, where implemented, it showed itself capable of resolving problems (only 0.5% of the cases could not be handled) as also of changing ongoing trends (more than 50% reduction in hospital admission rates). Individual assessment of each item of the programme indicated its bottlenecks. Regarding the epidemiology of respiratory diseases, it is observed that the major burden to health services comes from children aged less than five, and that the most important diseases are wheezing illnesses and pneumonia. Moreover, they were found to be significantly associated (p = 0.000) so that a child in the community presenting wheezing diseases is 5 times more likely to develop pneumonia than a child with any other respiratory diagnosis. Similarly, among the under five deaths it was found that the risk for pneumonia is 3 times greater for children who died presenting wheezing diseases than it is for children with any other sort of diagnosis. In conclusion, the programme is deemed to be efficient and effective but its efficacy is marred by administrative flaws. The successful control of respiratory problems in childhood is related to a proper appreciation of the importance of wheezing diseases.     

The spectrum of cervical cystic hygroma

Cystic hygromas (benign tumours of the lymphatic system or lymphangiomas) occur predominantly in the head and neck region of infants and children. They can be grouped into three prognostic categories: (1) simple cystic hygroma; (2) cystic hygroma with oropharyngeal involvement; and (3) cystic hygroma with mediastinal involvement. At the Royal Children's Hospital, Melbourne, during a 16 year period (1973–1988) 47 of 122 (39%) patients admitted with a lymphangioma were classified as cervical cystic hygroma. Simple cystic hygromas, presenting as a lump, occurred in 33 children. In 28, uncomplicated excision was possible. Nine children presented at birth with cystic hygroma with oro-pharyngeal involvement, 5 of whom had severe respiratory distress. All 9 required multiple excisions; death occurred in 1. Cervicomediastinal cystic hygroma occurred in 5 children presenting between birth and 2 years. Mediastinal involvement was confirmed by chest X-ray. All children had thoracocervical excision without early complications; 2 had cervical recurrence. Offprint requests to: N. A. Myers     

High-level expression of rat PC12 tyrosine hydroxylase cDNA in Escherichia coli: purification and characterization of the cloned enzyme.

A rat cDNA containing the complete coding sequence for rat tyrosine hydroxylase (tyrosine 3-monooxygenase, EC 1.14.16.2) was isolated from a rat PC12 cDNA library and subcloned in a bacterial expression plasmid, and large amounts of functional enzyme were produced in Escherichia coli. The recombinant enzyme was purified approximately 20-fold to a final specific activity of 1.8 mumol/min per mg of protein, with a yield of 30%. As much as 1 mg of pure protein could be obtained from 1 g of wet bacterial cells. The purified hydroxylase was shown to be homogeneous by denaturing polyacrylamide electrophoresis and isoelectric focusing. Amino acid analysis of the N terminus (25 residues) revealed 100% identity with rat PC12 tyrosine hydroxylase, as deduced from its cDNA sequence. Several of the kinetic properties of the recombinant enzyme resembled those of the native PC12 hydroxylase. However, in contrast to the native enzyme, the purified recombinant hydroxylase was shown to be in an activated form. Phosphorylation with cAMP-dependent protein kinase resulted in stoichiometric incorporation of phosphate, but the kinetic profile of the recombinant enzyme was unaffected. Several clues to these differences are considered that may provide insight into the structural features important to the regulation of tyrosine hydroxylase.