Use of extracorporeal membrane oxygenation for bronchoscopic removal of a tracheal foreign body in a child.

BACKGROUND: Bronchoscopic removal of a foreign body is a common emergency procedure in paediatric otolaryngology. It is potentially life-threatening, as complete airway obstruction caused by the foreign body can lead to hypoxic cardiac arrest during the manipulation of the object. CASE REPORT: This paper presents a child who had aspirated a foreign body that could not be extracted conventionally via rigid bronchoscopy in the first instance. Subsequently, it was extracted at repeat bronchoscopy under controlled respiratory conditions maintained by an extracorporeal gas exchange circuit - extracorporeal membrane oxygenation, using a polypropylene hollow fibre oxygenator commonly employed in cardiac surgery (rather than a more expensive polymethyl pentene oxygenator commonly used in extracorporeal membrane oxygenation). CONCLUSION: Extracorporeal membrane oxygenation use can be considered in exceptional cases of upper airway emergencies, even in resource-poor settings, and can avoid more hazardous thoracotomy and bronchotomy procedures.

Barriers for Cataract Treatment among Elderly in Sri Lanka.

Cataract is still the leading cause of blindness. Many government institutes and voluntary organizations in Sri Lanka are providing free treatment services to patients with cataract. Still people are not patronizing the available free services; thus they have to live with impaired vision or blindness. This paper describes the barriers for cataract treatment among the population over 60 years of age. Out of 470 elders, 379 were found to have some kind of cataract. This study demonstrated lack of awareness and knowledge, socioeconomic factors, and misconceptions as the main barriers for cataract treatment which has led to a lower cataract surgery rate irrespective of the high cataract prevalence reported. Findings of this study highlight the importance of cataract as a common health problem in elderly and need for removal of the barriers for its treatment which should be given due prominence in the formulation of public health policy in Sri Lanka at the earliest.

Lean non-alcoholic fatty liver disease (lean NAFLD): characteristics, metabolic outcomes and risk factors from a 7-year prospective, community cohort study from Sri Lanka.

INTRODUCTION: While patients with non-alcoholic fatty liver disease (NAFLD) are mostly overweight or obese, some are lean. METHODS: In a community-based follow-up study (baseline and follow-up surveys performed in 2007 and 2014), we investigated and compared the clinical characteristics, body composition, metabolic associations and outcomes, and other risk factors among individuals with lean (BMI < 23 kg/m2) NAFLD, non-lean (BMI ≥ 23 kg/m2) NAFLD and those without NAFLD. To investigate associations of selected genetic variants, we performed a case-control study between lean NAFLD cases and lean non-NAFLD controls. RESULTS: Of the 2985 participants in 2007, 120 (4.0%) had lean NAFLD and 816 (27.3%) had non-lean NAFLD. 1206 (40.4%) had no evidence of NAFLD (non-NAFLD). Compared to non-lean NAFLD, lean NAFLD was commoner among males (p < 0.001), and had a lower prevalence of hypertension (p < 0.001) and central obesity (WC < 90 cm for males, < 80 cm for females) (p < 0.001) without prominent differences in the prevalence of other metabolic comorbidities at baseline survey. Of 2142 individuals deemed as either NAFLD or non-NAFLD in 2007, 704 NAFLD individuals [84 lean NAFLD, 620 non-lean NAFLD] and 834 individuals with non-NAFLD in 2007 presented for follow-up in 2014. There was no difference in the occurrence of incident metabolic comorbidities between lean NAFLD and non-lean NAFLD. Of 294 individuals who were non-NAFLD in 2007 and lean in both 2007 and 2014, 84 (28.6%) had developed lean NAFLD, giving an annual incidence of 4.1%. Logistic regression identified the presence of diabetes at baseline, increase in weight from baseline to follow-up and a higher educational level as independent risk factors for the development of incident lean NAFLD. NAFLD association of PNPLA3 rs738409 was more pronounced among lean individuals (one-tailed p < 0.05) compared to the whole cohort sample. CONCLUSION: Although lean NAFLD constitutes a small proportion of NAFLD, the risk of developing incident metabolic comorbidities is similar to that of non-lean NAFLD. A PNPLA3 variant showed association with lean NAFLD in the studied population. Therefore, lean NAFLD also warrants careful evaluation and follow-up.

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.

Associations between the schizophrenia susceptibility gene ZNF804A and clinical outcomes in psychosis.

We sought to test the hypothesis that the rs1344706 A allele will be associated with worse clinical outcome in first-episode psychosis. A data linkage was set up between a large systematic study of first-episode psychosis and an electronic health-record case register at the South London and Maudsley NHS Foundation Trust--a large provider of secondary mental-health care. A sample of 291 patients, who presented with a first psychotic episode (ICD10 diagnoses F20-29 or F30-33) and in whom the rs1344706 genotype had been assayed, were followed to examine the duration of mental-health in-patient care during the 2 years following first service contact, as a primary outcome. Secondary outcome measures were whether or not an in-patient episode occurred and the number of in-patient episodes during this period. A strong association was found between the number of rs1344706 A alleles and the cumulative duration of mental-health in-patient stay over the 2 years since initial presentation. In the 84.2% who experienced an in-patient episode during this period, the mean duration of admission was an additional 38 days for each A allele increment. Therefore, in addition to its potential role as a risk factor for psychosis, the ZNF804A rs1344706 A allele is associated with worse clinical outcome.

Statistical characteristics of anterior fontanelle size at birth of term Sri Lankan new borns: a descriptive cross sectional study.

INTRODUCTION: Assessing the anterior fontanelle size is an important component of routine neonatal examination. For meaningful interpretation of fontanelle size, normal reference values are essential. Normal values for the fontanelle size in Sri Lankan newborns are not available. OBJECTIVES: To investigate characteristics of anterior fontanelle size at birth in Sri Lankan babies. METHODS: A descriptive cross sectional study was carried out between October and November 2010. Horizontal and vertical dimensions of the anterior fontanelle were measured in 2215 normal term babies, between 12 to 24 hours after birth. A practical and simple method was used to measure fontanelle size. Average fontanelle size was calculated by adding horizontal and vertical dimensions and dividing by two. RESULTS: Mean of the average fontanelle size for the total sample was 2.55 cm (for males 2.57 cm and for females 2.52 cm). Longitudinal dimension was significantly higher than the horizontal in both sexes (p<0.001). Frequency distribution curves of fontanelle size followed a normal distribution in both sexes. The ninety seventh centile and third centile for the average fontanelle size were 4.5 cm and 0.9 cm respectively. CONCLUSIONS: Babies with an average anterior fontanelle size more than 4.5 cm or less than 0.9 cm need further follow up. Further studies are needed to evaluate the accuracy of these cut off values.

Pro-inflammatory cytokines IL-1ß and TNF-α are not associated with blood homocysteine concentration in Alzheimer's disease.

Increased concentrations of pro-inflammatory blood cytokines and plasma homocysteine (Hcy) are frequently reported in Alzheimer's disease (AD). Hcy appears to have immunomodulating and pro-inflammatory activities. Further, emerging evidence from animal and non-AD human studies implicates Hcy in potentiating the activities of pro-inflammatory cytokines; Hcy toxicity may also, in part, be mediated by these cytokines. As little is known about the potential relationship between these inflammatory markers specific to AD, the aim of this study was to assess potential impact of Hcy on the widely reported increases in cytokine concentrations in AD. Blood concentrations of two pro-inflammatory cytokines, IL-1ß and TNF-α, along with Hcy were assessed in 40 AD patients and 30 cognitively intact controls. Mean blood concentrations of IL-1ß and TNF-α differed significantly between the AD and control groups (p=0.001 and p<0.001 resp). This difference survived adjustment for age and gender on logistic regression. Hcy was significantly correlated with age only in the patient (rs=0.38, p=0.02) but not the control group. There was no significant correlation between IL-1ß and Hcy, and between TNF-α, and Hcy in either the AD or the control group. Hence, our AD data did not replicate results obtained from animal and non-AD human studies which have linked pro-inflammatory cytokines concentrations to Hcy. A different inflammatory focus may exist in AD which may be influenced at least in a significant part by non-vascular pathogenesis. However, these results indirectly support the notion that the observed mild hyperhocysteinemia in AD may be due to non-inflammatory factors.

PM(10)-bound polycyclic aromatic hydrocarbons: biological indicators, lung cancer risk of realistic receptors and 'source-exposure-effect relationship' under different source scenarios.

Cancer has become a critical health issue in the world heritage city Kandy, Sri Lanka. Polycyclic aromatic hydrocarbons (PAHs), one of persistent organic pollutants, in the atmosphere may be a major etiological factor in lung carcinogenicity. Over the very high concentrations of ambient air PAHs reported in Kandy, this paper is focused on setting priorities to control human exposure to PAHs in prevention of cancer. On re-appraisal of the classical indicator benzo(a)pyrene (B[a]P) for atmospheric PAHs-related carcinogenicity, B[a]P failed to reflect the toxicity completely and may not be the sole indicator for risk assessment studies in complex multi-sourced urban environments. The excess lifetime lung cancer risks of atmospheric PAHs with 'less than lifetime exposure' were assessed based on both 'B[a]P toxic equivalents' and 'B[a]P surrogate epidemiological' approach of risk quantification, over emissions characterized urban, suburban, and rural areas of Kandy. In urban heavy traffic areas, PAH-related additional cancer burden has been 942 million(-1) over 30 y of exposure. Over the whole study area, ∑p-PAHs show strong correlation (r=0.8) to the predicted risk levels. While the urban and suburban predicted cancer risk levels could not show significant correlation to their emission sources indicating the real complexity in mega urban environments, the rural lung cancer risk levels correlated perfectly with the source, firewood combustion. Policy decisions on environment and health could be based on established correlations among 'emission sources-exposures-health effects'. The priority for "analysis of options and policy formulation to reduce inhalation PAHs exposure of population in Kandy" was considered "moderate to high".

A community-based cluster randomised trial of safe storage to reduce pesticide self-poisoning in rural Sri Lanka: study protocol.

BACKGROUND: The WHO recognises pesticide poisoning to be the single most important means of suicide globally. Pesticide self-poisoning is a major public health and clinical problem in rural Asia, where it has led to case fatality ratios 20-30 times higher than self-poisoning in the developed world. One approach to reducing access to pesticides is for households to store pesticides in lockable "safe-storage" containers. However, before this approach can be promoted, evidence is required on its effectiveness and safety. METHODS/DESIGN: A community-based cluster randomised controlled trial has been set up in 44,000 households in the North Central Province, Sri Lanka. A census is being performed, collecting baseline demographic data, socio-economic status, pesticide usage, self-harm and alcohol. Participating villages are then randomised and eligible households in the intervention arm given a lockable safe storage container for agrochemicals. The primary outcome will be incidence of pesticide self-poisoning over three years amongst individuals aged 14 years and over. 217,944 person years of follow-up are required in each arm to detect a 33% reduction in pesticide self-poisoning with 80% power at the 5% significance level. Secondary outcomes will include the incidence of all pesticide poisoning and total self-harm. DISCUSSION: This paper describes a large effectiveness study of a community intervention to reduce the burden of intentional poisoning in rural Sri Lanka. The study builds on a strong partnership between provincial health services, local and international researchers, and local communities. We discuss issues in relation to randomisation and contamination, engaging control villages, the intervention, and strategies to improve adherence.

Prevalence of inflammatory bowel disease in two districts of Sri Lanka: a hospital based survey.

BACKGROUND: Inflammatory bowel disease (IBD) is being increasingly diagnosed in Asia. However there are few epidemiological data from the region. METHODS: To determine prevalence and clinical characteristics of IBD, a hospital-based survey was performed in the Colombo and Gampaha districts (combined population 4.5 million) in Sri Lanka. Patients with established ulcerative colitis (UC) and Crohn's disease (CD), who were permanent residents of these adjoining districts, were recruited from hospital registries and out-patient clinics. Clinical information was obtained from medical records and patient interviews. RESULTS: There were 295 cases of IBD (UC = 240, CD = 55), of which 34 (UC = 30, CD = 4) were newly diagnosed during the study year. The prevalence rate for UC was 5.3/100,000 (95% CI 5.0-5.6/100,000), and CD was 1.2/100,000 (95% CI 1.0-1.4/100,000). The incidence rates were 0.69/100,000 (95% CI 0.44-0.94/100,000) for UC and 0.09/100,000 (95% CI 0.002-0.18/100,000) for CD. Female:male ratios were 1.5 for UC and 1.0 for CD. Mean age at diagnosis was (males and females) 36.6 and 38.1y for UC and 33.4 and 36.2y for CD. Among UC patients, 51.1% had proctitis and at presentation 58.4% had mild disease. 80% of CD patients had only large bowel involvement. Few patients had undergone surgery. CONCLUSIONS: The prevalence of IBD in this population was low compared to Western populations, but similar to some in Asia. There was a female preponderance for UC. UC was mainly mild, distal or left-sided, while CD mainly involved the large bowel.

The use of iron-fortified wheat flour to reduce anemia among the estate population in Sri Lanka.

The use of flour fortified with 66 mg/kg of electrolytic or reduced iron to reduce the prevalence of anemia was determined in a two-year, double-blind, controlled trial. The trial was conducted in Sri Lanka among preschoolers between 9 and 71 months old, primary schoolers 6 to 11 years old, and nonpregnant women. At baseline, 18.4% of the preschoolers had low hemoglobin (Hb) concentrations. Neither electrolytic nor reduced iron had an effect on Hb concentration among preschoolers. Only 7% of the primary schoolers were anemic at the start of the trial and, again, fortification had no effect on Hb concentration. Twenty-nine percent of women had a low Hb at outset and there was no evidence that fortification had an effect on Hb in this group. The findings from this study suggest that fortification of flour with electrolytic iron or reduced iron was not beneficial in reducing anemia in this population. This was probably due to the low prevalence of anemia and low bioavailability of the fortificant iron. Fortification with either iron fortificant was acceptable.

Glycaemic indices of different varieties of rice grown in Sri Lanka.

OBJECTIVE: Varieties of red raw rice are widely believed to have a better nutritional quality. The physiological effects of consuming different varieties of rice may not be so. The glycaemic index has been developed as an indicator of the physiological effect of foods. It is the glycaemic response of a 50 g carbohydrate portion of food expressed as a percentage of that of a standard. The objective of this study was to determine the glycaemic indices of different varieties of rice grown in Sri Lanka. DESIGN: Digestible carbohydrate content of 11 varieties of rice flour and bread were determined. Fasting blood samples followed by half-hourly samples for two hours were drawn after giving portions of either cooked rice or bread containing 50 g carbohydrate each. SETTING: Fibre mill in Gampaha district. SUBJECTS: Twenty-two fibre mill workers aged between 25 and 50 years. MEASUREMENTS: The area under the blood glucose curve (AUC) for varieties of rice for a subject was calculated. Average AUC of 3 values for bread were calculated. Glycaemic index of each variety of rice was determined from the above variables. RESULTS: Glycaemic indices of varieties of rice differ. The glycaemic indices of varieties of red raw rice varied between 56 and 73 and the variety Bg 350 had the lowest glycaemic index. There was no significant difference between mean glycaemic index of varieties of white raw and some varieties of red raw rice (p = 0.2). Parboiled varieties of red raw rice had a significantly lower glycaemic index than white raw rice (p = 0.04) and some of the red raw rice (p = 0.005). CONCLUSIONS: The glycaemic index cannot be predicted from the colour of the rice grain. Red parboiled varieties of rice and Bg 350 can be recommended for patients with diabetes.

Ancistrolikokines A-C: new 5,8'-coupled naphthylisoquinoline alkaloids from Ancistrocladus likoko.

Three new naphthylisoquinoline alkaloids, ancistrolikokines A-C (1-3), have been isolated and structurally assigned from Ancistrocladus likoko, as well as the known compound korupensamine A (4). Their 5,8'-coupling hints at a close biogenetic relationship of A. likoko to other Central African Ancistrocladus species. Compounds 1-4 showed good to moderate antimalarial activities when evaluated in vitro against the NF54 and K1 strains of Plasmodium falciparum.

Tropane alkaloids from Erythroxylum zeylanicum O.E. Schulz (Erythroxylaceae).

Six tropane alkaloids were isolated from the Sri Lankan endemic plant Erythroxylum zeylanicum O.E. Schulz (Erythroxylaceae) and structurally elucidated by NMR and MS measurements. Three of them, erythrozeylanines A [1R,3R,5S,6R-6-acetoxy-3-(3',4',5'-trimethoxybenzoyloxy)tropane], B [cis-3 beta-(cinnamoyloxy)tropane], and C [cis-6 beta-acetoxy-3 alpha-(cinnamoyloxy)tropane] are new, whereas the others have already been found in other Erythroxylum species. For the first time, the absolute configuration of a tropane alkaloid (erythrozeylanine A) has been determined by quantum chemical CD calculations.

TNFalpha*2 marks high risk of severe disease during Plasmodium falciparum malaria and other infections in Sri Lankans.

We have investigated the association between alleles of the genes for tumour necrosis factor-alpha (TNF-alpha) and TNF-beta and severity of disease during malarial (Plasmodium falciparum) and other infections in the Sri Lankan population. Patients were categorized as having either (i) uncomplicated malaria, (ii) severe and complicated malaria, or (iii) severe and complicated infection in which a diagnosis of malaria had been excluded. For all the patients, as well as for a group of matched healthy controls, TNF-alpha and TNF-beta allelic types were identified using the polymerase chain reaction (PCR) and allele-specific oligonucleotide probes and restriction enzyme digestion. The odds in favour of carrying the TNFalpha*2 allele, mainly of the heterozygous genotype (TNFalpha*1,*2), were two to three times greater among individuals with severe disease, of either malarial or other infectious origin, relative to healthy controls or to those with uncomplicated malarial infections. No significant risk was associated with either of the alleles of TNF-beta.

The ParaSight-F dipstick test as a routine diagnostic tool for malaria in Sri Lanka.

Blood from 1053 persons who presented for treatment at outpatient clinics of government health institutions in Sri Lanka, and 250 who took part in a blood survey for malaria, was examined by thick blood film microscopy under routine field conditions, and by the ParaSight-F dipstick method. All the samples were also examined microscopically under laboratory conditions when 4 times the number of microscope fields were examined. Compared with this reference standard, the sensitivity and specificity of the ParaSight-F test were 90.2% and 99.1%, and those of microscopy in the field were 92.4% and 98.4% respectively, there being no statistically significant difference between the 2 methods. The ParaSight-F test reading correlated significantly and positively with the intensity of clinical disease of patients but not with their peripheral parasitaemia, indicating that it may be a more accurate measure of the true parasite load than microscopy, which detects only parasites which are in the peripheral blood and not those which are sequestered in deep organs. The ParaSight-F test, however, failed to detect Plasmodium falciparum infections with only gametocytes in the blood (19.6% of the infected blood samples in this study). The time taken for a patient to revert to negativity by the ParaSight-F test was also significantly longer, up to 14 d. This would make the test unsuitable for checking the response to antimalarial treatment within 14 d. In an endemic area it would therefore fail to detect drug resistant populations of parasites.

Engendering development theory from the standpoint of women.

PIP: Although the field of "women and development" emerged as an aftermath of the UN Decade for Women, development planners have treated gender and development as interrelated but analytically distinct by simply tacking the category "women" onto established frameworks or considering women the social "contexts" of development projects. This paper challenges this tendency with a consideration of how the global process of development is conditioned by and constitutive of gender roles and relations in specific cultural contexts. The paper presents a framework for a distinctly feminist political economy of development that moves development theory from its present impasse caused by challenges to the Marxism that has dominated critical development theory. This post-impasse framework poses Marx's theory of exploitation against the experiences of women garment workers in Free Trade Zones in Sri Lanka to illustrate how industrial development through free market channels is necessarily, not merely coincidentally, gendered. Therefore, the framework reveals the importance of engendering development theory itself. The paper opens with an introduction and continues with an exploration of the current theoretical impasse and post-impasse theory. The paper continues with a discussion of standpoint epistemology as the basis for women-centered research, a description of the research on the impact of factory employment on women from rural villages, a consideration of women's proletarianization in terms of the rise of the "new world order," a feminist reading of Marx's theory of exploitation from the standpoint of the garment workers, and an acknowledgement of the challenge posed by this application of standpoint methodology to the study of development to the current rejection by some Western feminists of universalizing categories such as "gender" and "women."^ieng

In vitro and in vivo inhibition of ortho- and paramyxovirus infections by a new class of sulfonic acid polymers interacting with virus-cell binding and/or fusion.

A series of sulfonic acid polymers were shown to be potent and selective inhibitors of respiratory syncytial virus (RSV) and influenza A virus. The compounds inhibit the replication of RSV and influenza A virus in HeLa and MDCK cells, at concentrations of 0.16 and 4.0 micrograms/ml, respectively, and are nontoxic to growing cells at concentrations of > 100 micrograms/ml. The mode of antiviral action of the sulfonic acid polymers can be ascribed to inhibition of virus-cell fusion (for influenza A virus) or inhibition of both virus-cell binding and fusion (for RSV). The sulfonic acid prototype PAMPS [poly(2-acrylamido-2-methyl-1-propanesulfonic acid)], when administered intranasally to mice as a single dose of 10 or 50 mg per kg of body weight at the time of infection, completely inhibited influenza A virus replication (in lungs) and virus-associated lung consolidation in immunocompetent mice and completely protected NMRI and SCID (severe combined immune deficiency) mice against influenza A virus-associated mortality. When administered 1 h before or after virus inoculation, no protective effect was observed at a dose of 10 or 100 mg/kg. Sulfonic acid polymers exert selective inhibitory effects on RSV and influenza A virus replication.

Structure-activity relationship studies with symmetric naphthalenesulfonic acid derivatives. Synthesis and influence of spacer and naphthalenesulfonic acid moiety on anti-HIV-1 activity.

Symmetric bis(naphthalenesulfonic acid) derivatives containing a variety of spacers have been synthesized and evaluated for anti-HIV-1 activity in four assay systems. In the assay that measured inhibition of HIV-1-induced cytopathogenicity using a laboratory strain (HTLV-IIIB), a hexamethylene and octamethylene spacer derivative of 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid emerged as the most potent derivatives. The hexamethylene spacer analog exhibited an in vitro therapeutic index that was > 120. Selected derivatives were tested in the giant cell formation assay. In this assay, the most potent derivative was, again, the hexamethylene compound. Evaluation of selected derivatives against a clinical isolate of HIV-1 (HE strain) revealed that the hexamethylene derivative was the most potent compound. In the assay that measured the inhibition of HIV-1-induced cytopathogenesis in human peripheral blood lymphocytes, the hexamethylene compound emerged as the most active derivative, demonstrating a 50% inhibitory concentration of 1.3 microM. These studies clearly demonstrate that certain naphthalenesulfonic acid moieties when coupled to specific spacers were synergistic in producing anti-HIV-1 activity at nontoxic concentrations. In the 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid series, shortening of the spacer length, preferably with a flexible polymethylene chain, was highly beneficial for increasing anti-HIV-1 potency.

An efficient preparative chromatographic method for the separation and purification of low molecular weight naphthalenesulfonic acid mixtures.

These studies describe an efficient preparative method of separating and purifying polar mixtures of low molecular weight (mol wt) sulfonic acid derivatives containing one to six sulfonic acid moieties and possessing mol wt differences ranging from less than 100 and up to 650. This gel permeation chromatography procedure successfully separates materials with similar charges, requires no prepurification step, uses inexpensive apparatus, and employs water as the eluant. This technique has quantitative recovery and is potentially applicable to other anionic separations.