Relation of smoking and low-to-moderate alcohol consumption to change in cognitive function: a longitudinal study in a defined community of older persons

To determine whether smoking habits and alcohol consumption are related to changes in cognitive function, the authors conducted a prospective, community-based study of persons aged 65 years and over in East Boston, Massachusetts. In 1982 and again in 1985, the subjects were given three brief tests of cognitive function: immediate memory, digit span, and a mental status questionnaire, which primarily assessed orientation. The 1,201 individuals who performed well in 1982 were included in linear regression analyses of 3-year change in performance, adjusted for age, sex, education, and income. Relative to nonsmoking, current smoking, past smoking, and pack-years were not significantly related to change in immediate memory. None was significantly related to change in orientation. Only pack-years was significantly related to normal change score in digit span (normal change score change per unit of predictor = 0.001, 95% confidence interval 0.0003-0.002). Low-to-moderate alcohol consumption during the month preceding baseline testing was not significantly related to a subsequent 3-year change in performance in two of the three tests. However, people who consumed a very small amount of alcohol had a normal change score that was 0.088 (95% confidence interval 0.015-0.160) better for digit span than did nondrinkers. This study provides evidence that the reported levels of smoking and alcohol use among older persons are not consistent or substantial predictors of the longitudinal change in cognitive function observed in a community.

Maintaining mobility in late life. I. Demographic characteristics and chronic conditions

To assess the role of demographic factors and chronic conditions in maintaining mobility in older persons, this study utilized longitudinal data collected as part of the Established Populations for Epidemiologic Studies of the Elderly between 1981 and 1987 on 6,981 men and women aged 65 years and older in East Boston, Massachusetts; Iowa and Washington counties, Iowa; and New Haven, Connecticut. Results are presented for those who at baseline reported intact mobility, defined as the ability to climb stairs and walk a half mile without help, and who were followed annually for up to 4 years for changes in mobility status. Age, income, education, and chronic conditions present at baseline and occurring during follow-up were evaluated for their association with loss of mobility. Over the follow-up period, 55.1% of subjects maintained mobility, 36.2% lost mobility, and 8.7% died without evidence of mobility loss prior to death. In both men and women, increasing age and lower income levels were associated with increased risk of losing mobility, even after controlling for the presence of chronic conditions at baseline. After adjustment for age, income, and chronic conditions, lower education levels were a significant risk factor for mobility loss in men, but not in women. Baseline reports of previous heart attack, stroke, high blood pressure, diabetes, dyspnea, and exertional leg pain were associated with small but significant risks for mobility loss. There was a stepwise increase in the risk of mobility loss according to the number of chronic conditions present at baseline that was very consistent between men and women. The occurrence during the study of a new heart attack, stroke, cancer, or hip fracture was associated with a substantially greater risk of mobility loss than was associated with the presence of these conditions at baseline.

Topical treatment of cutaneous leishmaniasis in Belize: in vitro and in vivo studies with Leishmania mexicana

Strains of Leishmania mexicana isolated from Belizian patients were found to be highly susceptible to paromomycin sulphate (PR) treatment. This drug at 100 micrograms ml-1 destroyed 85-99.5% of in vitro cultivated Leishmania promastigotes within 4 days of exposure to the drug. Leishmania promastigotes inoculated into the base of the tail of Balb/c mice caused the development of local lesions several weeks after infection. These lesions were totally cleared of parasites after 20 days of topical treatment with PR ointment, comprised of 15% paromomycin sulphate and 12% methylbenzethonium chloride in soft white paraffin. Similar results were also obtained with L. braziliensis infections. Isoenzyme analysis was found to be the method of choice for parasite strain identification. Excreted factor serotyping was only partially effective and promastigote agglutination gave negative results.

Established populations for epidemiologic studies of the elderly: study design and methodology

A project initiated by the intramural Epidemiology, Demography and Biometry Program of the National Institute on Aging, entitled "Established Populations for Epidemiologic Studies of the Elderly" (EPESE), has developed information on death, chronic conditions, disabilities, and institutionalization for representative samples of elderly people living in communities. The EPESE consists of prospective epidemiologic studies of approximately 14,000 persons 65 years of age and older in four different communities: East Boston, Massachusetts; two rural counties in Iowa; New Haven, Connecticut; and segments of five counties in the north-central Piedmont area of North Carolina. The study design includes an initial baseline household interview followed by continued surveillance of morbidity and mortality. Participants are re-contacted annually in conjunction with the collection of data on cause of death and factors related to hospitalization and nursing home admissions. Concurrently, the investigators developed substudies focused on specific problems of the elderly. The value of this research lies in the longitudinal design which allows for analyses aimed at identifying risk factors of diseases, disabilities, hospitalizations, institutionalization, and mortality.

Isoenzyme variation within the genus Cryptosporidium

Soluble extracts of the oocysts of Cryptosporidium parvum had demonstrable, but low, activities of malate dehydrogenase (MDH, EC. 1.1.1.37), carboxylesterase (ES, EC 3.1.1.1) and lactate dehydrogenase (LDH, EC. 1.1.1.27) following thin-layer starch-gel electrophoresis. Much higher activities of glucose phosphate isomerase (GPI, EC. 5.3.1.9) and phosphoglucomutase (PGM, EC. 2.7.5.1) were found, and zymograms of these two enzymes were used to characterise isolates of C. parvum from human, bovine, ovine and cervine sources, C. muris from the brown rat and C. baileyi from young turkeys. PGM and GPI zymograms clearly distinguished between C. parvum, C. muris and C. baileyi. The five isolates of C. parvum showed the same electrophoretic mobility for GPI, whereas the PGM mobility of the single human isolate of C. parvum examined was clearly different from that of the other isolates. This is the first report of the use of isoenzymes to distinguish between species and isolates of Cryptosporidium.

The effects of tumor necrosis factor after removal of the gut

Tumor necrosis factor (TNF) is thought to be an important mediator of the septic response; intravenous administration of this cytokine provokes a wide range of metabolic and hemodynamic effects which closely resemble those known to follow endotoxin administration. These effects include damage to gut mucosa. Since the gut constitutes an internal reservoir of endotoxin and bacteria it is possible that some of TNF's effects might be secondary to an increased absorption of these agents. To test this hypothesis TNF was given both to intact dogs and also to animals in which the gut had been removed, from duodenum to anus ("enterectomy"). The data indicates that the effects of TNF upon systemic pressure, white count, and cortisol and glucagon levels were not affected by prior removal of the gut. For most other parameters the findings were less clear but in general the changes in enterectomized dogs were qualitatively similar to those described in the intact animal. We conclude that the effects observed following TNF infusion in the dog are not dependent on the intestinal tract as a secondary source of bacteria or mediators.

Extrapyramidal signs and other neurologic findings in clinically diagnosed Alzheimer's disease. A community-based study

The association between findings on the neurologic examination and the clinical diagnosis of Alzheimer's disease was investigated among 467 individuals from a geographically defined community population. Participants were selected by stratified random sampling based on their memory performance in a population survey of community residents 65 years of age and older. Each participant underwent a structured medical, psychiatric, neurologic, and neuropsychologic examination. Of the 467 persons examined there were 134 cases of probable Alzheimer's disease and 167 control subjects. Multiple logistic regression analysis was used to estimate the degree to which the presence of each of several neurologic examination findings affected the age- and sex-adjusted relative odds of having clinically diagnosed Alzheimer's disease. The most striking associations with the diagnosis of Alzheimer's disease were seen with various measures of extrapyramidal dysfunction. These increased relative odds were not markedly affected by excluding from the analysis cases with severe cognitive impairment. The results suggest that involvement of the extrapyramidal system is a common finding in Alzheimer's disease.

Level of education and change in cognitive function in a community population of older persons

In a community population of persons over the age of 65, cognitive function was assessed using brief performance tests on two occasions 3 years apart. Those with fewer years of formal education consistently had greater declines in cognitive function, independently of age, birthplace, language of interview, occupation, and income. These prospective findings suggest that low educational attainment or a correlate predicts cognitive decline. It is not clear, however, whether this relation represents a direct effect of education on future cognition, whether education might be related to occurrence of a disease leading to cognitive decline in older persons, or whether education might be a surrogate for some variable not included in the study.

Gastrografin-induced aspiration pneumonia: a lethal complication of computed tomography

A 43-year-old man with dysphagia and a tendency to aspirate was found to have squamous cell carcinoma of the esophagus. Curative surgery was planned and preoperative computed tomography of the chest and abdomen was ordered. A ward nurse administered Gastrografin according to a "standing" order, 4 hours before the CT was to be done. The patient aspirated about 50 mL of Gastrografin, and went into cardiorespiratory arrest caused by pulmonary edema. He sustained severe brain damage and died. This is a first report of lethal aspiration of Gastrografin, given in preparation for CT. We advise alerting nurses who administer Gastrografin, especially to patients with dysphagia or impaired consciousness about the grave consequences that can result if the contrast agent is aspirated by the patient. We further advise that responsibility for using contrast agents in radiologic procedures be assumed by the radiologist and not by medical house staff.

Leishmania infecting man and wild animals in Saudi Arabia. 9. The black rat (Rattus rattus) a probable reservoir of visceral leishmaniasis in Gizan province, south-west Saudi Arabia

Twenty-two black rats (Rattus rattus) were captured in houses where parasitologically confirmed cases of human visceral leishmaniasis had been recorded in Al-Arda Emara, Gizan province, south-west Saudi Arabia. Four of the rats were found to be infected with Leishmania; isoenzyme characterization showed that 3 were infected with L. donovani sensu lato zymodeme LON42 and the fourth with L. infantum zymodeme LON49. L. donovani s.l. LON42 has also been isolated from human visceral leishmaniasis patients living in this area, while dogs, but not humans, have been found to be infected with L. infantum LON49 in this part of Saudi Arabia.

Effect of quassin on the metabolism of catecholamines in different life cycle stages of Culex quinquefasciatus

Quassin, a mosquito larvicide isolated from Quassia amara, inhibits tyrosinase activity in the larvae of Culex quinquefasciatus. Since tyrosinase is directly involved in sclerotisation of the cuticle, it is suggested that quassin, as a larvicide, inhibits development of the cuticle. In presence of quassin phenylalanine, tyrosine and L-dopa levels were increased in larvae. In the larval stages, mosquitoes have a high concentration of phenylalanine and tyrosine with the level of the latter being very high just before pupation and then declines sharply. Monoamine oxidase (MAO), an enzyme directly involved in the metabolism of catecholamines, remained unaffected by quassin, in fact the level of adrenaline also remained unchanged in larvae during quassin poisoning. MAO showed high variation in its activity between synthetic and natural substrates. Tyramine is not a substrate for MAO. Tyrosinase activity was high in developing stages and negligibly low in adults and showed specificity to L-dopa. Phenylalanine and tyramine are unaffected by tyrosinase. Blood feeding did not influence the activity of both these enzymes.

Light to moderate alcohol consumption and mortality in the elderly

OBJECTIVE

To determine whether there is a relationship of low to moderate alcohol consumption with cardiovascular mortality in the elderly.

DESIGN

Prospective cohort studies with 5-year mortality follow-up.

SETTING

Three populations of community-dwelling elders.

PARTICIPANTS

Population-based cohorts of men and women, aged 65 or older, in three populations. Subjects with prior myocardial infarction, stroke, or cancer, as well as those lacking alcohol consumption data, were excluded from statistical analyses leaving 2,694 subjects in East Boston, Massachusetts, 2,293 subjects in Iowa, and 1,904 subjects in New Haven, Connecticut.

MAIN OUTCOME MEASUREMENTS

Alcohol consumption, total mortality, cardiovascular mortality, and cancer mortality.

RESULTS

Low to moderate alcohol consumption was associated with statistically significant lowered total as well as cardiovascular mortality in East Boston and New Haven. The relative risks of total mortality for low to moderate consumers of alcohol compared to those consuming no alcohol in the previous year were 0.7 (95% CI 0.6-0.8) in East Boston and 0.6 (95% CI 0.5-0.8) in New Haven. For cardiovascular mortality, the RRs were 0.6 in East Boston and 0.5 in New Haven (95% CI's exclude null). These results persisted after control for potential confounding variables. In Iowa, there were no significant differences in total or cardiovascular mortality according to alcohol consumption patterns. For cancer mortality, there were no significant associations with alcohol consumption in any of the three populations.

CONCLUSIONS

These data suggest that the relationship of low to moderate alcohol consumption with reduced total and cardiovascular mortality, which are well documented in middle age, also occur in older populations.

Childhood blood pressure tracking correlations corrected for within-person variability

The correlation coefficient between initial and subsequent blood pressure (BP) measurements is referred to as the tracking correlation. Childhood BP tracking correlations, although positive, have been considered too low to make accurate predictions for an individual. These correlations, however, can be raised substantially by averaging BP over multiple weekly visits in each year, which partially accounts for within-person variability. In a cohort of 333 school children, we measured BP 3 times on each of 4 successive weekly visits, in each of 4 consecutive years, using a random-zero sphygmomanometer. Approximately 90 per cent of subjects had data for one or more follow-up years, and 75 per cent of subjects who entered in the first year had data for all four years. With a model that allows estimation of correlations and that uses all available longitudinal data, we calculated tracking correlations completely corrected for within-person variability, the statistical equivalent of measuring BP on an infinite number (infinity) of visits and measurements per visit. Age-sex adjusted tracking correlations for 3 years of follow-up based on the means from 1,2,3,4, and infinity visits are, for systolic BP, 0.43, 0.56, 0.62, 0.66, and 0.73, respectively, and for diastolic BP, 0.20, 0.37, 0.46, 0.50, and 0.70, respectively. With longer follow-up, the use of corrected tracking correlations would allow determination of the maximal extent to which childhood BP can predict adult levels, and therefore the usefulness of screening to identify children at high risk of developing hypertension.

Population prevalence estimates from complex samples

Epidemiologic studies are often designed to severe several purposes. The complex sampling plans necessary to ensure an adequate number of cases, a similar age distribution among cases and controls, or other important design constraints for comparative studies may make the additional goal of estimating prevalence in the population or in important subgroups difficult to attain with existing computer software, which typically assumes simple random sample selection. We consider here various methods for estimating overall and subgroup prevalence from complex samples, including crude prevalences, direct standardization of prevalences, and standardization using logistic regression to smooth the sampling group prevalences. We illustrate these methods using a complex sample to estimate the prevalence of Alzheimer's disease in an urban community. A simulation study under various models in this setting is also described. We conclude that the use of logistic regression to smooth sampling group prevalences before standardization is an effective method for estimation of overall prevalence, provided that the adequacy of fit of a logistic model is carefully checked.

Relation of smoking and alcohol consumption to incident Alzheimer's disease

The authors examined the effects of smoking and alcohol use in a prospective community-based study of incident Alzheimer's disease. Two in-home interviews of the total elderly population of East Boston, Massachusetts, conducted in 1982 and 1985 were used to sample individuals for clinical evaluation for Alzheimer's disease. A total of 513 persons underwent detailed clinical evaluation including neurologic, neuropsychologic, and psychiatric evaluation to diagnose Alzheimer's disease. In weighted logistic regression controlled for age, sex, and education, the estimated odds ratio of Alzheimer's disease was 0.7 (95% confidence interval 0.3-1.4) for ever smokers compared with never smokers. For 40 pack-years of smoking, the odds ratio of Alzheimer's disease was 0.8 (95% confidence interval 0.6-1.1). Consumption of 1 oz (30 ml) of alcohol per day was associated with an odds ratio of 1.1 (95% confidence interval 0.8-1.5). These results suggest that recent mild-to-moderate consumption of alcohol is not substantially related to incidence of Alzheimer's disease and that smoking does not increase risk of the disease.

Risk factors for delirium in hospitalized elderly

OBJECTIVE

To determine risk factors for delirium in elderly hospitalized patients.

DESIGN

Cohort analytic study. Using a reliable and valid instrument for detection of delirium, we prospectively followed up a cohort of elderly patients admitted to an acute care hospital. Using standardized criteria, we collected risk factor data from patient medical records.

SETTING

General medical and surgical wards of a tertiary-care hospital.

PATIENTS

Patients (n = 325) were 65 years of age or older, from either a geographically defined community or a long-term-care institution. We studied those patients (n = 291) not delirious on first evaluation. Fifty-seven patients or their families refused participation.

MAIN OUTCOME MEASURES

Incidence of delirium and risk factors calculated as adjusted odds ratios (ORs).

MAIN RESULTS

Delirium developed in 91 patients. By stepwise logistic regression, the independent risk factors for in-hospital delirium included prior cognitive impairment (OR, 8.97; 95% confidence interval [CI], 3.99 to 20.14), age over 80 years (OR, 5.22; 95% CI, 2.60 to 10.46), fracture on admission (OR, 6.57; 95% CI, 2.23 to 19.33), symptomatic infection (OR, 2.96; 95% CI, 1.42 to 6.15), and male sex (OR, 2.40; 95% CI, 1.19 to 4.84). Among medication groups, only neuroleptic use (OR, 4.48; 95% CI, 1.82 to 10.45) and narcotic use (OR, 2.54; 95% CI, 1.24 to 5.18) were independently associated with delirium. Anticholinergic use was not associated with delirium.

CONCLUSIONS

Delirium in hospitalized patients is most closely associated with factors already present on admission such as prior cognitive impairment, advanced age, and fracture. In the hospital, use of neuroleptics and narcotics and the presence of infection are less strongly associated with this syndrome.

Murine teratology and pharmacokinetics of the enantiomers of sodium 2-ethylhexanoate

A mouse model for the induction of exencephaly with sodium (+/-)-2-ethylhexanoate has been developed using multiple administration regimes. With three consecutive administrations at one-half-day intervals, the most sensitive time to induce exencephaly was Gestational Days 8-9. Using the racemic substance it was determined that the SWV strain was more sensitive to the induction of exencephaly than the C57BL/6NCrlBR strain. The enantiomers of 2-ethylhexanoic acid were separated via preparative HPLC to greater than 99.8% optical purity, and greater than 99% purity according to a gas chromatographic analysis. It was demonstrated that the (R)-enantiomer is a more potent teratogen than the (S)-enantiomer for the induction of exencephaly as well as malformations of other organ systems. Pharmacokinetic analyses for each of the enantiomers were performed in maternal plasma, maternal muscle, and embryo. The pharmacokinetics showed that the peak concentration (Cmax) for both enantiomers in the three compartments was approximately equivalent and was attained within 15 min following the third administration. The area under the concentration versus time curve values for the two enantiomers were approximately 10% higher for the (R)-antipode because of a slightly slower elimination of this compound. There was negligible (or no) racemization of the two enantiomers in the biological samples. The results suggest that teratologic differences in the enantiomers of sodium 2-ethylhexanoate are not due to differences in the concentrations of these antipodes in the embryo, but more likely result from the specific interaction of the enantiomers with chiral molecules in the embryo.

Delirium. The occurrence and persistence of symptoms among elderly hospitalized patients

We evaluated the occurrence and persistence of delirium in 325 elderly patients admitted to a teaching hospital from either a defined community or a long-term care facility. Of the study participants, 34 (10.5%) had Diagnostic and Statistical Manual of Mental Disorders, Third Edition--defined delirium at initial evaluation; of the remaining patients, 91 (31.3%) developed new-onset delirium. An additional 110 patients also experienced individual symptoms of delirium without meeting full criteria. Preexisting cognitive impairment and advanced age were associated with increased risk of incident delirium in the community sample but not the institutional one. Delirium was not associated with an increased risk of mortality, but it was associated with a prolonged hospital stay and an increased risk of institutional placement among community-dwelling elderly. Only five patients (4%) experienced resolution of all new symptoms of delirium before hospital discharge, and only 20.8% and 17.7%, respectively, had resolution of all new symptoms by 3 and 6 months after hospital discharge. These data suggest that delirium is a common disorder that may be substantially less transient than currently believed and that incomplete manifestations of the syndrome may be frequent.

Assessing the validity of childhood blood pressure screening: unbiased estimates of sensitivity, specificity, and predictive values

Blood pressure measurement in childhood can be considered as a screening test for future blood pressure levels. Evaluating this test involves calculating sensitivities, specificities, and predictive values for a blood pressure measurement at an initial time for predicting underlying true blood pressure at a subsequent time. We demonstrate the use of childhood blood pressure tracking correlations that are corrected for within-person variability to calculate unbiased estimates of these test characteristics. In a cohort of 333 schoolchildren, we measured blood pressure on multiple visits in each of 4 successive years. Using these data for within-person variances and corrected tracking correlations, and U.S. population data for means and total variances, we tabulated positive predictive values, sensitivities, and specificities for the case of predicting a 9-year-old male's true systolic blood pressure 3 years later. For example, if a 9-year-old's average blood pressure from 4 visits is 115 mmHg, the probability of his true blood pressure being greater than 116 mmHg (90th percentile) at age 12 is 0.50. With longer follow-up, the use of predictive values, sensitivities, and specificities that incorporate corrected correlations should allow determination of the accuracy of predicting adult blood pressure from childhood values, and therefore the usefulness of screening children for those at high risk of developing hypertension.

Alzheimer's disease

Alzheimer's disease is one of the most severe and most common chronic diseases of older persons. Because occurrence of the disease is strongly related to age, its public health impact is likely to continue to increase as the population ages. As with many other diseases, a diagnosis of Alzheimer's disease is made through a combination of clinical history, physical, and neurologic examination, and laboratory evaluation. Because the dominant feature of this disease is its effect on cognition, its diagnosis requires careful evaluation of cognitive function usually with formal neuropsychological performance testing. Clinical evaluation of persons for Alzheimer's disease has four objectives: (1) to determine as accurately as possible if the person has dementia; (2) if dementia is present, to determine whether its presentation and course are consistent with a diagnosis of Alzheimer's disease; (3) to assess evidence for any alternate diagnoses, especially if the presentation and course are atypical for Alzheimer's disease; and (4) to evaluate evidence of other, coexisting, diseases that may contribute to the dementia, with strong emphasis on conditions that might respond to treatment. There is no reliable antemortem diagnostic test for Alzheimer's disease; the main purpose of laboratory testing is to identify other conditions that might cause or exacerbate dementia. Pathologically, Alzheimer's disease is characterized by the presence of two lesions on microscopic examination of the brain: neuritic plaques and neurofibrillary tangles. Both lesions can be seen in the brains of older persons without dementia. However, they are found in greater numbers in the neocortex and hippocampus with Alzheimer's disease. Caring for patients with Alzheimer's disease is demanding and requires compassion and skills that go beyond the choices among sophisticated and effective therapies that characterize much of modern medical practice. The current lack of effective pharmacotherapy for cognitive dysfunction in Alzheimer's disease should not obscure that there are many areas in which intervention can improve quality of life for both the patient and the caregiver. Achieving success in these areas typically requires that the physician work effectively with providers of many other medical and nonmedical services. Community resources, advocacy, behavior management, and experimental therapies and procedures, should be discussed with the family of each patient. In addition, persons with mild disease should be promptly informed of their diagnosis in order to obtain their wishes regarding life prolonging measures and extended care options.

Relation of blood pressure to cognitive function in the elderly

Clinical case-control studies of the relation between blood pressure and cognitive function have generally found lower function among hypertensives. Most of these studies were small and incompletely controlled for confounders. Two population-based studies have yielded conflicting results. This study examines cognitive function over the entire range of blood pressure in a defined elderly population. A questionnaire administered in the home to 3,809 persons aged greater than or equal to 65 years in East Boston, Massachusetts, in 1982 and 1983 contained four brief cognitive tests: immediate memory, delayed memory, a mental status questionnaire, and digit span. In linear regression analyses adjusting for age, sex, and education, the direction of the association was not consistent among the tests. An increase in diastolic pressure of 10 mmHg was associated with an increase of 1.0 in percentile scores on the immediate memory test (95% confidence interval (CI) -0.04 to 1.9); with an increase of 1.1 in percentile scores on the delayed memory test (95% CI -0.1 to 2.3); with a decrease of -0.8 in percentile scores on the mental status questionnaire (95% CI -1.8 to 0.2); and with a decrease of -0.9 in percentile scores on the attention test (95% CI -1.5 to -0.2). These results suggest that blood pressure is not a substantial contributor to cognitive status in the elderly.

Automatic indexing of abstracts via natural-language processing using a simple thesaurus

The authors describe CLARIT processing as an approach to automatic indexing. They also explore two elements of the indexing process, identifying concepts in text and selecting concepts to reflect the perspective of a domain.

Toward representations for medical concepts

The authors characterize the problems inherent to mapping across or combining terms from different vocabularies, focusing especially on MeSH and SNOMED. They also describe the exploration of the development of a frame-based representation of SNOMED.

Larvicidal efficacy of Quassin against Culex quinquefasciatus

Crushed aqueous extracts of leaf, wood, bark and flowers of Quassia amara showed antilarval activity against C quinquefasciatus. Quassin has been identified to be the antilarval principle present in this plant and was effective against mosquito larvae at a concentration of 6 ppm. Quassin was present to the extent of 0.1 to 0.14 per cent (average 0.12%) on a dry weight basis in wood of Q. amara. This compound is an unsaturated lactone and it gave a positive response to the Legal test, characteristic of unsaturated lactones. Quassin lost its antilarval activity on treatment with strong alkalies. Quassin was over five times as active as carbaryl, a synthetic antilarval agent.