Curative-Intent Radiotherapy for Squamous Cell Carcinoma of the Head and Neck in Sri Lanka: The Impact of Radiotherapy Technique on Survival.

AIMS: We conducted a retrospective analysis of patients with squamous cell carcinoma of the head and neck (SCCHN) treated with curative-intent radiotherapy at the National Cancer Institute of Sri Lanka to determine the impact of the treatment technique on disease-free survival (DFS). MATERIALS AND METHODS: SCCHN patients treated with radical radiotherapy or adjuvant postoperative radiotherapy from 2016 to 2017 were included in the study. Data on the following variables were collected by reviewing clinical and radiotherapy treatment records: age, gender, tumour site, stage, time to delivery of radiotherapy, use of neoadjuvant chemotherapy, use of concurrent radiosensitising chemotherapy and treatment technique. DFS, defined as the time to death, tumour recurrence or loss to follow-up, was the primary end point and outcomes were compared between patients treated with intensity-modulated radiotherapy (IMRT) in linear accelerators and those treated with conventional radiotherapy in cobalt teletherapy units. Univariate and multivariate analyses were carried out on known prognostic variables. RESULTS: In total, 408 patients were included in the study, with 138 (34%) being treated with IMRT in the linear accelerator. More than 75% of patients were of stage III or IV at diagnosis. The 2-year DFS of the whole cohort was 25% (95% confidence interval 21-30%). Patients treated with IMRT in the linear accelerator had a superior DFS in comparison with those treated with conventional radiotherapy in the cobalt teletherapy units (P < 0.001, hazard ratio 0.64, 95% confidence interval 0.5-0.82). Higher stage, cobalt treatment and use of neoadjuvant chemotherapy were adversely associated with DFS on multivariate analysis. CONCLUSION: A large proportion of patients with SCCHN treated with curative-intent radiotherapy in Sri Lanka had locally advanced disease and DFS was superior in patients treated with IMRT in the linear accelerator.

Risk estimates of cardiovascular diseases in a Sri Lankan community.

OBJECTIVES: Quantifying the risk of cardiovascular disease (CVD) in a community is important in planning preventive strategies, but such data are limited from developing countries, especially South Asia. We aimed to estimate the risks of coronary heart disease (CHD), total CVD, and CVD mortality in a Sri Lankan community. METHODS: A community survey was conducted in an urban health administrative area among individuals aged 35-64 years, selected by stratified random sampling. Their 10-year CHD, total CVD, and CVD mortality risks were estimated using three risk prediction tools: National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III), Systematic Coronary Risk Evaluation (SCORE), and World Health Organisation/ International Society of Hypertension (WHO/ISH) charts. RESULTS: Among study participants (n=2985), 54.5% were females, and mean age (SD) was 52.4 (7.8) years. According to NCEP-ATP III ('hard' CHD risk), WHO/ISH (total CVD risk), and SCORE (CVD mortality risk) criteria, 25.4% (95% CI 23.6-27.2), 8.2% (95% CI 7.3-9.2), and 11.8 (95% CI 10.5-13.1) respectively were classified as at 'high risk'. The proportion of high risk participants increased with age. 'High risk' was commoner among males (30.3% vs 20.6%, p<0.001) according to NCEPATP III criteria, but among females (9.7% vs. 6.7%, p<0.001) according to WHO/ISH criteria. No significant gender difference was noted in SCORE risk categories. CONCLUSIONS: A large proportion of individuals in this community are at risk of developing cardiovascular diseases, especially in older age groups. Risk estimates varied with the different prediction tools, and were comparatively higher with NCEP-ATP III charts.

A Comparison between Revised NCEP ATP III and IDF Definitions in Diagnosing Metabolic Syndrome in an Urban Sri Lankan Population: The Ragama Health Study.

Background. The prevalence of metabolic syndrome (MetS) within individual cohorts varies with the definition used. The aim of this study was to compare the prevalence of MetS between IDF and revised NCEP ATP III criteria in an urban Sri Lankan population and to investigate the characteristics of discrepant cases. Methods. 2985 individuals, aged 35-65 years, were recruited to the study. Anthropometric and blood pressure measurements and laboratory investigations were carried out following standard protocols. Results. Age and sex-adjusted prevalences of MetS were 46.1% and 38.9% by revised NCEP and IDF definitions, respectively. IDF criteria failed to identify 21% of men and 7% of women identified by the revised NCEP criteria. The discrepant group had more adverse metabolic profiles despite having a lower waist circumference than those diagnosed by both criteria. Conclusion. MetS is common in this urban Sri Lankan cohort regardless of the definition used. The revised NCEP definition was more appropriate in identifying the metabolically abnormal but nonobese individuals, especially among the males predisposed to type 2 diabetes or cardiovascular disease. Further research is needed to determine the suitability of the currently accepted Asian-specific cut-offs for waist circumference in Sri Lankan adults.

Genomic organization, 5'flanking region and tissue-specific expression of mouse phosphofructokinase C gene.

Using a combination of mouse bacterial artificial chromosome (BAC) genomic library screening, long-range polymerase chain reaction (PCR) amplification, genomic walking and DNA sequencing, we have characterized the intron/exon boundaries, the sizes of each intron and 5' flanking region of the mouse PFK-C gene. The gene spans approximately 55 kb and comprises 22 exons separated by 21 introns. All intron/exon splice junctions conform to the GT/AG rule. The mouse PFK-C gene organization is similar to that of the human and rabbit PFK-A and human and mouse PFK-B genes. However, PFK-C has much larger intronic sequences throughout the gene. Anchored PCR was performed to amplify about 1.0 kb of genomic DNA upstream of the translational start site. Sequence analysis of the PFK-C 5' flanking region revealed that it is devoid of TATA and CAAT boxes at the usual positions, but it contained several putative binding sites for transcription factors AP1, GATA1, NKX2.5 and STAT. The 5' flanking region was not enriched in GC dinucleotides and lacked CpG islands and putative binding sites for SP1. Four transcription initiation sites have been identified by full-length RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) between -61 and -32 bp from the translation initiation codon. Reverse transcription-PCR analysis revealed that PFK-A, PFK-B and PFK-C genes were expressed, in all mouse tissues tested, at varying levels. PFK-A mRNA was more abundantly expressed in all tissues than were the PFK-B and PFK-C genes. Based on the mouse PFK-C signal normalized to 18S rRNA, the PFK-C mRNA was expressed at the highest levels in the brain, heart, thymus and testicles, whereas low levels were observed in the kidney, liver, muscle, and lung.

Identification of allosteric sites in rabbit phosphofructo-1-kinase.

Earlier studies indicated an evolutionary relationship between bacterial and mammalian phosphofructo-1-kinases (PFKs) that suggests duplication, tandem fusion, and divergence of catalytic and effector binding sites of a prokaryotic ancestor to yield in eukaryotes a total of six organic ligand binding sites. The identities of residues involved in the four binding sites for allosteric ligands in mammalian PFK have been inferred from this assumed relationship. In the current study of the C isozyme of rabbit PFK, two arginine residues that can be aligned with important residues in the catalytic and allosteric binding sites of bacterial PFK and that are conserved in all eukaryotic PFKs were mutated. Arg-48 was suggested previously to be part of either the ATP inhibitory or the adenine nucleotide activating site. However, the mutant enzyme showed only slightly less sensitivity to ATP inhibition and was fully activatable by adenine nucleotides. On the other hand, sensitivity to citrate and 3-phosphoglycerate inhibition was lost, indicating an important role for Arg-48 in the binding of these allosteric effectors. Mutation of Arg-481, homologous to an active site residue in bacterial PFK, prevented binding and allosteric activation by fructose 2,6-bisphosphate. A new relationship between the allosteric sites of mammalian PFK and bacterial PFK is proposed.

Cloning, sequencing, expression, and purification of the C isozyme of mouse phosphofructokinase.

The cDNA of mouse phosphofructo-1-kinase isozyme C was cloned and sequenced. The coding region translates into a protein of 85,473 Da containing 785 amino acids. The cDNA includes 57 base pairs of a 5'-untranslated region and a 3' untranslated region of 284 base pairs containing a polyadenylation signal, AUUAAA, located 17 bases upstream from the poly(A) tail. The cDNA was ligated into a pET vector and transformed into a pfk(-) strain of Escherichia coli (DF1020) that contained the pLysS plasmid and an integrated lambda DE3 prophage that includes a single copy of the gene for T7 RNA polymerase under control of the inducible LacUV5 promoter. Conditions for maximum induction of soluble enzyme activity was developed to produce up to 2400 units of soluble enzyme activity per liter of growth medium. The enzyme could be purified to homogeneity with a yield of approximately 60% by a single purification step on ATP-Sepharose.

Effect of mebendazole therapy during pregnancy on birth outcome.

BACKGROUND: In areas endemic for hookworm, routine antenatal mebendazole therapy could greatly reduce the prevalence of anaemia in pregnancy. At present, however, this is not a widely accepted control strategy because of a lack of data on the safety of the drug. We assessed the effect of mebendazole therapy during pregnancy on birth outcome. METHODS: A cross-sectional study was done in Sri Lanka, where prescription of mebendazole to women in the second trimester of pregnancy is recommended. Two hospitals were chosen for the study, and women who gave birth there between May, 1996, and March, 1997, were recruited. We compared the rates of major congenital defects, stillbirth, perinatal death, and low birthweight (< or = 1500 g) among babies of mothers who had taken mebendazole during pregnancy with those whose mothers had not taken an anthelmintic (controls). FINDINGS: The rate of major congenital defects was not significantly higher in the mebendazole group than in the control group (97 [1.8%] of 5275 vs 26 [1.5%] of 1737; odds ratio 1.24 [95% CI 0.8-1.91], p=0.39). Among 407 women who had taken mebendazole in the first trimester (contrary to medical advice), 10 (2.5%) had major congenital defects (odds ratio vs controls 1.66 [0.81-3.56], p=0.23). The proportions of stillbirths and perinatal deaths were significantly lower in the mebendazole group (1.9 vs 3.3%, 0.55 [95% CI 0.4-0.77]), as was the proportion of low-birthweight babies (1.1 vs 2.3%, 0.47 [95% CI 0.32-0.71]). INTERPRETATION: Mebendazole therapy during pregnancy is not associated with a significant increase in major congenital defects, but our results indicate that it should be avoided during the first trimester. This therapy could offer beneficial effects to pregnant women in developing countries, where intestinal helminthiases are endemic.

Use of Transgenic Plants with Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Antisense DNA to Evaluate the Rate Limitation of Photosynthesis under Water Stress.

The biochemical lesion that causes impaired chloroplast metabolism (and, hence, photosynthetic capacity) in plants exposed to water deficits is still a subject of controversy. In this study we used tobacco (Nicotiana tabacum L.) transformed with "antisense" ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) DNA sequences to evaluate whether Rubisco or some other enzymic step in the photosynthetic carbon reduction cycle pathway rate limits photosynthesis at low leaf water potential ([psi]w). These transformants, along with the wild-type material, provided a novel model system allowing for an evaluation of photosynthetic response to water stress in near-isogenic plants with widely varying levels of functional Rubisco. It was determined that impaired chloroplast metabolism (rather than decreased leaf conductance to CO2) was the major cause of photosynthetic inhibition as leaf [psi]w declined. Significantly, the extent of photosynthetic inhibition at low [psi]w was identical in wild-type and transformed plants. Decreasing Rubisco activity by 68% did not sensitize photosynthetic capacity to water stress. It was hypothesized that, if water stress effects on Rubisco caused photosynthetic inhibition under stress, an increase in the steady-state level of the substrate for this enzyme, ribulose 1,5-bisphosphate (RuBP), would be associated with stress-induced photosynthetic inhibition. Steady-state levels of RuBP were reduced as leaf [psi]w declined, even in transformed plants with low levels of Rubisco. Based on the similarity in photosynthetic response to water stress in wild-type and transformed plants, the reduction in RuBP as stress developed, and studies that demonstrated that ATP supply did not rate limit photosynthesis under stress, we concluded that stress effects on an enzymic step involved in RuBP regeneration caused impaired chloroplast metabolism and photosynthetic inhibition in plants exposed to water deficits.

Heterogenous stomatal closure in response to leaf water deficits is not a universal phenomenon.

The extent and occurrence of water stress-induced "patchy" CO(2) uptake across the surface of leaves was evaluated in a number of plant species. Leaves, while still attached to a plant, were illuminated and exposed to air containing [(14)C]CO(2) before autoradiographs were developed. Plant water deficits that caused leaf water potential depression to -1.1 megapascals during a 4-day period did result in heterogenous CO(2) assimilation patterns in bean (Phaseolus vulgaris). However, when the same level of stress was imposed more gradually (during 17 days), no patchy stomatal closure was evident. The patchy CO(2) assimilation pattern that occurs when bean plants are subjected to a rapidly imposed stress could induce artifacts in gas exchange studies such that an effect of stress on chloroplast metabolism is incorrectly deduced. This problem was characterized by examining the relationship between photosynthesis and internal [CO(2)] in stressed bean leaves. When extent of heterogenous CO(2) uptake was estimated and accounted for, there appeared to be little difference in this relationship between control and stressed leaves. Subjecting spinach (Spinacea oleracea) plants to stress (leaf water potential depression to -1.5 megapascals) did not appear to cause patchy stomatal closure. Wheat (Triticum aestivum) plants also showed homogenous CO(2) assimilation patterns when stressed to a leaf water potential of -2.6 megapascals. It was concluded that water stress-induced patchy stomatal closure can occur to an extent that could influence the analysis of gas exchange studies. However, this phenomenon was not found to be a general response. Not all stress regimens will induce patchiness; nor will all plant species demonstrate this response to water deficits.