Association of gestational diabetes and breastfeeding on obesity prevalence in predominately Hispanic low-income youth.

OBJECTIVE: The goal of this study was to examine if breastfeeding duration by gestational diabetes mellitus status impacted the prevalence of obesity in offspring. METHODS: Data were obtained from a 2011 phone survey with caregivers of low-income children (2-4 years) participating in the Women, Infants and Children programme in Los Angeles County. The final sample included 2295 children, 84% Hispanic and 48% female. Chi-square and binary logistic regression were used to assess gestational diabetes status and breastfeeding duration on the prevalence of obesity, with the following a priori covariates: child's ethnicity, birth weight, age in months and sex. RESULTS: Breastfeeding and gestational diabetes were significantly associated with obesity prevalence (P < 0.01). Using gestational diabetes mellitus and no breastfeeding as the referent category, gestational diabetes mellitus offspring who were breastfed ≥12 months had a 72% decrease in obesity prevalence (adjusted odds ratio = 0.28, confidence interval 0.89-0.03, P = 0.05). CONCLUSIONS: These findings suggest that > 12 months of breastfeeding duration in the gestational diabetes mellitus group and any duration of breastfeeding in the non-gestational diabetes mellitus mothers is needed to reduce obesity levels in a primarily Hispanic population.

Effects of parental nativity and length of stay in the US on fruit and vegetable intake among WIC-enrolled preschool-aged children.

Exposure to US culture is negatively associated with fruits and vegetables (F&V) intake. Our goal was to investigate how parent's nativity and length of stay in the US influences preschoolers' F&V intake. We analyzed survey data from 2,352 children, aged 36-60 months, who participate in the Supplemental Nutrition Program for Women, Infants and Children (WIC) in Los Angeles County. Using multiple linear regression, we examined children's F&V intake by parent's nativity and years in the US, adjusting for possible confounders. Children of foreign born parents who had lived in the US for <10 years consumed fewer servings of vegetables than children of US born parents and of foreign born parents who had lived in the US for ≥10 years. Children of newer immigrant families may be at greater risk for consuming poor-quality diets. Research to identify determinants of poor diet quality among children of immigrant families may increase the effectiveness of WIC in addressing this population's nutritional needs.

Mortality and cancer registration experience of the Sellafield workers known to have been involved in the 1957 Windscale accident: 50 year follow-up.

This paper studies the mortality and cancer morbidity of the 470 male workers involved in tackling the 1957 Sellafield Windscale fire or its subsequent clean-up. Workers were followed up for 50 years to 2007, extending the follow-up of a previously published cohort study on the Windscale fire by 10 years. The size of the study population is small, but the cohort is of interest because of the involvement of the workers in the accident. Significant excesses of deaths from diseases of the circulatory system (standardised mortality ratio (SMR) = 120, 95% CI = 103-138; 194 deaths) driven by ischaemic heart disease (IHD) (SMR = 133, 95% CI = 112-157, 141 deaths) were found when compared with the population of England and Wales but not when compared with the population of Northwest England (SMR = 105, 95% CI = 90-120 and SMR = 115, 95% CI = 97-136 respectively). When compared with those workers in post at the time of the fire but not directly involved in the fire the mortality rate from IHD among those involved in tackling the fire was raised but not statistically significantly (rate ratio (RR) = 1.11, 95% CI = 0.92-1.33). A RR of 1.11 is consistent with an excess relative risk of 0.65 Sv(-1) as reported in an earlier study of non-cancer mortality in the British Nuclear Fuels plc cohort of which these workers are a small but significant part. There was a statistically significant difference in lung cancer mortality (RR = 2.18, 95% CI = 1.05-4.52) rates between workers who had received higher recorded external doses during the fire and those who had received lower external doses. Comparison of the mortality rates of workers directly involved in the accident with workers in post, but not so involved, showed no significant differences overall. On the basis of the use of a propensity score the average effect of involvement in the Windscale fire on all causes of death was - 2.13% (se = 3.64%, p = 0.56) though this difference is not statistically significant. The average effect of involvement in the Windscale fire was - 5.53% (se = 3.81, p = 0.15) for all cancers mortality and 6.60% (se = 4.03%, p = 0.10) for IHD mortality though neither figure was statistically significant. This analysis of the mortality and cancer morbidity experience of those Sellafield workers involved in the 1957 Windscale fire does not reveal any measurable effect of the fire upon their health. Although this study has low statistical power for detecting small adverse effects, due to the relatively small number of workers, it does provide reassurance that no significant health effects are associated with the 1957 Windscale fire even after 50 years of follow-up.

Cancer chemoprevention drug targets.

Cancer chemoprevention is a new approach in the management of cancer. Traditional cytotoxic chemotherapeutic approaches cannot cure most advanced solid malignancies. Chemoprevention can be defined as the use of non-cytotoxic drugs and natural agents to block the progression to invasive cancer. Chemoprevention can either prevent DNA damage that initiates the neoplastic transformation process or reverses the progression of pre-invasive lesions. Epidemiological observations, experimental evidence from animal carcinogenesis models, knock-out models, cancer cell lines and clinical trials have shown the efficacy of this approach. Recent advances in our understanding of carcinogenesis have led to the synthesis of new drugs that target specific receptors. Non-steroidal anti-inflammatory drugs target the prostaglandin pathway. The identification of the role of cyclooxygenase-2 in epithelial carcinogenesis led to the synthesis of selective cyclooxygenase-2 inhibitors (Celecoxib). Celecoxib was subsequently approved for the prevention of colon polyps in familial adenomatous polyposis after the completion of a randomized clinical trial. The large chemoprevention clinical trial with the selective estrogen receptor modulator, tamoxifen, showed the benefit of tamoxifen in the prevention of breast cancer in high-risk women. Retinoids and rexinoids target the retinoid receptors and have a role in chemoprevention of aerodigestive, hepatic and cervical neoplasia. Selenium, an inhibitor of the glutathione peroxidase system, is being tested in the chemoprevention of prostate cancer and lung cancer. The different isoforms of vitamin E (tocopherols) may be chemopreventive. Recent evidence indicates that gamma-tocopherol may be a more powerful chemopreventive than the alpha-tocopherol. The review details the rationale, experimental and clinical evidence and the drug targets of the chemopreventive agents that are currently in various phases of clinical development.

Comparison of the adaptive functioning of children prenatally exposed to alcohol to a nonexposed clinical sample.

BACKGROUND: Several studies show impairments in the social and adaptive behaviors of children prenatally exposed to alcohol. However, there remains limited consensus on whether the alcohol exposure directly affects social functioning or whether its effect is mediated by deficits in IQ. In addition, no studies have investigated whether deficits in social functioning are significantly more pronounced in children prenatally exposed to alcohol than in children referred to psychiatric treatment who were not prenatally exposed. We explored the effect of alcohol exposure on social and adaptive functioning and explored whether or not social and adaptive functioning are significantly more impaired in children prenatally exposed to alcohol than in a clinical sample of children. METHODS: A sample of 33 alcohol-exposed children was compared with a sample of 33 clinic-referred nonexposed children. The groups were compared on measures of communication, daily living skills, and socialization. The groups were matched on sex, age, IQ, and outpatient or inpatient status. RESULTS: Analyses revealed that the prenatally alcohol-exposed children did not differ significantly from the nonexposed children in any of the domains of adaptive functioning. However, with age, exposed children showed a more rapid decline in socialization standard scores compared with the nonexposed clinical sample. CONCLUSIONS: Young children who were exposed to alcohol prenatally show deficits in all domains of adaptive functioning. Although these deficits do not seem to differ from those exhibited by young children with psychiatric problems but no prenatal exposure, deficits in socialization behavior of prenatally exposed children may become more significant with age.

Glucans exhibit weak antioxidant activity, but stimulate macrophage free radical activity.

Polymeric carbohydrates have been reported to modulate inflammatory responses in vitro and in vivo. Previous reports suggest that certain carbohydrate polymers, such as (1-->3)-beta-D-glucans, may possess free radical scavenging activity. If glucans are free radical scavengers then it might explain, in part, the ability of these ligands to modulate inflammatory responses. The present study examined the free radical scavenging activity of a variety of carbohydrate polymers and the effect of the polymers on free radical levels in a murine macrophage cell line. All of the carbohydrates exhibited concentration dependent antioxidant effects (EC(50) range = 807 to 43 microg/ml). However, the antioxidant activity for the carbohydrates was modest in comparison with PDTC (EC(50) = 0.13 microg/ml) and the carbohydrate concentration required for antioxidant activity was high (x EC(50) = 283 microg/ml). The antioxidant ability of the polymers was greater (p < .05) than their monosaccharide constituents, i.e., dextrose EC(50) = 807 vs. glucan sulfate EC(50) = 43 microg/ml. Coincubation of glucans with murine J774a.1 cells increased free radical levels when compared to controls. Therefore, the weak free radical scavenging activity of glucan polymers cannot explain their modulatory effect on inflammatory responses in tissue culture and/or disease models of inflammation.

Selection of peptides with semiconductor binding specificity for directed nanocrystal assembly.

In biological systems, organic molecules exert a remarkable level of control over the nucleation and mineral phase of inorganic materials such as calcium carbonate and silica, and over the assembly of crystallites and other nanoscale building blocks into complex structures required for biological function. This ability to direct the assembly of nanoscale components into controlled and sophisticated structures has motivated intense efforts to develop assembly methods that mimic or exploit the recognition capabilities and interactions found in biological systems. Of particular value would be methods that could be applied to materials with interesting electronic or optical properties, but natural evolution has not selected for interactions between biomolecules and such materials. However, peptides with limited selectivity for binding to metal surfaces and metal oxide surfaces have been successfully selected. Here we extend this approach and show that combinatorial phage-display libraries can be used to evolve peptides that bind to a range of semiconductor surfaces with high specificity, depending on the crystallographic orientation and composition of the structurally similar materials we have used. As electronic devices contain structurally related materials in close proximity, such peptides may find use for the controlled placement and assembly of a variety of practically important materials, thus broadening the scope for 'bottom-up' fabrication approaches.

Influence of vitamin A injection before mating on oocyte development, follicular hormones, and ovulation in gilts fed high-energy diets.

Previous research revealed that treatment with vitamin A approximately 5 d before ovulation may increase litter size in weaned sows and improve embryonal survival in gilts fed high-energy diets that reduced embryonal survival. For the current study, the hypothesis was that administration of vitamin A before ovulation would alter development of follicles and oocytes in a way favorable to enhanced embryonal survival. (Landrace x Large White) x (Duroc x Hampshire) gilts (n = 44) were fed 11.0 Mcal ME x gilt(-1) x d(-1) beginning 7 d after second estrus and given (i.m.) corn oil or 1 x 10(6) IU of vitamin A (retinyl palmitate) on d 15 after second estrus. Gilts were checked for estrus every 4 h, mated naturally at third estrus, and assigned randomly to undergo midventral laparotomy beginning at 24 to 28, 28 to 32, 32 to 36, or 36 to 40 h after onset of third estrus. At laparotomy, ovulated oocytes and early-stage embryos were recovered from oviducts, and ovaries were removed for aspiration of oocytes and granulosa cells from unovulated follicles. Oocytes and embryos were stained for assessment of stage of development. Granulosa cells were cultured to assess their ability to secrete progesterone. Follicular fluid was assayed for progesterone, estradiol-17beta, IGF-I, and PGF2alpha. Treatment with vitamin A altered development of oocytes and embryos by decreasing the percentage at the germinal vesicle stage and increasing the percentage at advanced stages. Mean stage of development was increased by vitamin A, but variation in stage was decreased. Among follicles matched by meiotic stage of oocyte, follicular fluid concentrations of progesterone, IGF-I, and PGF2alpha were greater in vitamin A-treated gilts than in controls, but treatment with vitamin A in vivo did not affect LH-stimulated or unstimulated secretion of progesterone by granulosa cells in vitro. These data provide evidence that vitamin A may influence embryonic development by advancing resumption of meiosis and altering follicular hormonal environment during follicle maturation.

Characterizing interactions between anxious mothers and their children.

The present study assessed interactions between anxious mothers and their children, using observational techniques to elucidate potential mechanisms of anxiety transmission. Results revealed that anxious mothers were less warm and positive in their interactions with their children, less granting of autonomy, and more critical and catastrophizing in comparison with normal control mothers. Maternal anxiety status appeared to be the primary predictor of maternal warmth during interactions. Child anxiety status was most predictive of maternal granting of autonomy behavior. Maternal behaviors exhibited during interactions were the most salient predictors of child anxiety, contributing more than maternal psychopathology or ongoing strain to the development of child anxiety. Interventions focusing on family interactions that take into account the contributions of both members of the dyad may be more effective in curbing transmission than interventions that solely address maternal or child symptomatology.

Infant predictors of cognitive development in an undernourished Kenyan population.

Assessments of infant sociability, motoric capacities, and nutritional factors were performed to elucidate early influences on infant development in an undernourished Kenya population. In this longitudinal study, infant social skills were assessed using both the Bayley Behavior Record and home observations during the first 6 months of the infants' lives. Abilities were measured using an adapted version of the Bayley scales of infant development at 6 and 30 months, and a short battery of cognitive measures at 5 years. Infant size measurements were used as indicators of infant nutritional status. Shorter and lighter infants, and those infants showing growth faltering in weight attainment, were significantly less sociable at 6 months than infants who were taller and maintained heavier weights. Infants with smaller arm circumferences displayed lower motor scores at 6 months and lower Bayley mental scores at 30 months than infants with greater arm circumference. Furthermore, infants who were more motorically able and socially adept at 6 months had higher Bayley scores at 30 months and higher verbal comprehension scores at 5 years.

Evidence that injection of vitamin A before mating may improve embryo survival in gilts fed normal or high-energy diets.

The hypothesis was that administration of vitamin A before ovulation would improve embryo survival in gilts fed a high-energy diet intentionally to reduce embryo survival. Forty crossbred ([Landrace x Large White] x [Duroc x Hampshire]) gilts were fed control (5.5 Mcal ME/d) or high-energy (11.0 Mcal ME/d) diets from 7 d after second estrus until 11 to 12 d after third estrus. Gilts in each dietary group received (i.m.) corn oil or retinyl palmitate (1 x 10(6) IU, vitamin A) on d 15 after second estrus and were mated at third estrus. Blood for determination of progesterone and estradiol was collected twice daily. The uterus and ovaries were removed on d 11 or 12 after third estrus for assessment of number of CL, and number, size and aromatase activity of embryos. Neither diet nor vitamin treatment affected number of CL. The high-energy diet exerted a negative effect on number of embryos (P = .09) and embryo survival (P = .07), whereas vitamin A exerted a positive effect on number of embryos (P = .07) and embryo survival (P = .08). The high-energy diet increased variation in embryo diameter, whereas vitamin A reduced variation in diameter and increased average diameter. Neither diet nor vitamin treatment influenced aromatase activity of embryos. Diet and vitamin treatment interacted with day to influence serum progesterone, but not estradiol. Injecting vitamin A before estrus restored embryo survival to normal levels in gilts fed high-energy diets, and this may be attributable to decreased variation in size of embryos.

The clinical assessment of a child's social and physical environment during health visits.

The quality of a child's home environment plays a critical role in long-term developmental status. The Pediatric Review and Observation of Children's Environmental Support and Stimulation (PROCESS) Inventory was developed to clinically assess aspects of the child's physical environment and the parent-child interaction during a health supervision visit. The final version was used with 76 mother-child pairs by two pediatricians. The Home Observation for Measurement of the Environment (HOME) Inventory was performed within 3 weeks on all pairs, and a laboratory observation of parent-child interaction was completed with 30 of the pairs. Correlations of the PROCESS with the HOME Inventory and parent-child interaction were 0.84 and 0.86 (less than 0.001), respectively. These significant correlations persisted while controlling for family income and education. When high and low scores of the HOME Inventory known to correlate with positive and negative developmental outcomes were cross-tabulated with PROCESS scores, low scores on the PROCESS identified 77% of low HOME Inventory scores and high scores on the PROCESS identified 95% of the high HOME Inventory scores. The PROCESS provides pediatricians a brief, easy-to-score, clinically useful, reliable, and valid method to measure children's home environments.

Effects of the respiratory tract on inhaled materials.

Inhalation exposure is often compared to intravenous or oral routes of administration with regard to the biological fate of inhaled materials. Such comparisons, however, overlook the contribution of respiratory tract enzymes to the metabolic fate and toxicity of inhaled materials. The effect of respiratory tract metabolism on the toxicity of inhaled materials is thought to be substantial for many compounds for the following reasons. (1) High concentrations of xenobiotic metabolizing enzymes occur in the nose and substantial concentrations occur in the lung. (2) The respiratory tract tissues are the first exposed to inhaled materials and are exposed to the highest concentrations (barring tissue specific uptake). (3) The products of respiratory tract metabolism may have different toxicities from those of hepatic metabolism. (4) Tissues at risk to toxic metabolites formed in the respiratory tract are different from those formed in the liver. These four reasons for concluding that respiratory tract metabolism may influence the toxicity of inhaled materials are backed by a solid body of expanding experimental data. Therefore, a complete assessment of the fate of inhaled materials should include assessment of potential contributions of respiratory tract metabolism.

In vivo metabolism of nasally instilled benzo[a]pyrene in dogs and monkeys.

Metabolism of inhaled materials deposited in the nasal cavity potentially influences their biological fate and toxicity. Metabolic enzymes, including cytochrome P-450-dependent monooxygenases, are not evenly distributed throughout the nasal cavity. The purpose of this study was to determine whether benzo[a]pyrene (BaP) deposited in the nasal cavity could be metabolized and cleared by the nasal tissue in the ethmoid and maxillary turbinate regions of Beagle dogs and cynomolgus monkeys. Nasopharyngeal mucus was collected at frequent intervals during periodic nasal instillations of BaP (and for dogs 24 h after instillation) for analysis of BaP and its metabolites. During and up to 48 h after nasal instillation of [14C]BaP, blood, urine and feces were collected to determine BaP clearance from the nose. High pressure liquid chromatographic analysis of organic phase extracts of nasopharyngeal mucus demonstrated that [14C]BaP instilled in either turbinate region was metabolized to dihydrodiols, quinones, phenols and tetrols in both species. Phenols were the major metabolic product, although all treated animals produced trans-7,8-dihydrobenzo[a]pyrene-7,8-diol. The dog mucus sampled at 24 h had no detectable radioactivity. The excreta from both species contained only small amounts of the instilled radioactivity. There was no distinctive pattern of metabolite production based on instillation site.

Technique for aerosol deposition restricted to the nose in beagle dogs.

A method was developed for exposing the nasal cavity of beagle dogs to a radiolabeled aerosol without exposure of the remainder of the respiratory tract. Deposition efficiency, using a test aerosol of 2.0-micron particles of 99mTc-sulfur colloid delivered to the nose, was 15 +/- 2% (mean +/- SE) of inhaled activity. Gamma camera imaging showed that maximum deposition occurred in the anterior third of the nasal cavity, which contained 78 +/- 4% (mean +/- SE) of the total deposited radioactivity. The middle-third of the nasal cavity received 13 +/- 3% and the posterior third 9 +/- 2% of the deposited radioactivity. Aerosol deposition in regions of the respiratory tract below the larynx was not detectable.

Suppression of luteal function in dogs by luteinizing hormone antiserum and by bromocriptine.

Beagle bitches were treated with equine anti-LH serum (ALHS) or the dopamine agonist bromocriptine at selected times during the 2-month luteal phase of the ovarian cycle or pregnancy. After a single injection of ALHS (10 ml, i.m.) at Day 42 of pregnancy (N = 2) or the ovarian cycle (N = 3), progesterone was reduced (P less than 0.05) to 7-24% of preinjection values within 1-2 days, and by 4-8 days returned to levels not different from those in control bitches treated with normal horse serum. Injections of bromocriptine (0.1 mg/kg, i.m.) daily for 6 days caused abrupt declines in progesterone which lasted 6-8 days in bitches treated at Day 8 or 22 of pregnancy (N = 5). In bitches treated at Day 42 of pregnancy (N = 3) or in non-pregnant cycles (N = 4) the bromocriptine treatment caused declines (P less than 0.05) in progesterone which were permanent, extensive (less than 2 ng/ml), and therefore abortive. The declines in progesterone in response to immunoneutralization of LH and to prolactin-lowering doses of a dopamine agonist demonstrate that normal luteal function in dogs requires both LH and prolactin.

Effect of aging on tracheal mucociliary clearance in beagle dogs.

Tracheal mucous velocity measurements were made in 24 beagle dogs in five age groups, using a gamma camera to detect movement of instilled 99mTc-macroaggregated albumin. Age groups were defined as immature (9-10 mo), young adult (2.8-3.0 yr), middle aged (6.7-6.9 yr), mature (9.6-9.8 yr), and aged dogs (13.6-16.2 yr). Mean velocities were 3.6 +/- 0.4 (SE) mm/min in the immature dogs, 9.7 +/- 0.6 mm/min in the young adults, 6.9 +/- 0.5 mm/min in the middle-aged dogs, 3.5 +/- 0.8 mm/min in the mature dogs, and 2.9 +/- 0.5 mm/min in the aged dogs. Tracheal mucous velocity was significantly (P less than 0.05) greater in the young adult and middle-aged groups compared with the immature, mature, and aged dogs. This pattern of age-related changes was noted to be similar to age-related changes described for certain pulmonary function measurements.

Clearance of nasal mucus in nonanesthetized and anesthetized dogs.

Clearance rates for nasal mucus in the maxillary turbinate region were measured in 8 Beagle dogs. 99mTc Macroaggregated albumin (10 microliters) was instilled in the nasal maxillary region of dogs under general anesthesia. A gamma camera was used to detect movement of the 99mTc macroaggregated albumin in the nose for 1 hour after it was instilled. Velocity of mucus was measured in the 8 dogs each under 3 conditions of anesthesia: anesthesia with pentobarbital given IV (20 mg/kg of body weight), anesthesia with halothane gas, and no anesthesia. Mean velocities (+/- SD) were 3.7 +/- 1.4 mm/min in dogs anesthetized with pentobarbital, 4.3 +/- 2.5 mm/min in dogs anesthetized with halothane, and 3.4 +/- 1.7 mm/min in awake dogs. The differences between the 3 anesthetic conditions were not significant at the P less than 0.05 level. Use of anesthesia at a light surgical plane provides a controlled method for measurement of clearance of nasal mucus with minimal alterations from the nonanesthetized state.

In vivo metabolism of nasally instilled dihydrosafrole [1-(3,4-methylenedioxyphenyl)propane] in dogs and monkeys.

Nasal metabolism of inhaled material may influence its biological fate and toxicity. The purpose of this study was to investigate, in a noninvasive and qualitative manner, the in vivo nasal metabolic activity towards 1-(3,4-methylenedioxyphenyl)propane (dihydrosafrole). Dihydrosafrole was the compound of choice as a representative of the methylenedioxyphenyl compounds. Methylenedioxyphenyl compounds, inhaled as essences or insecticide synergists, have complex interactions with cytochrome P-450-dependent monooxygenases, causing both inhibition and induction. Clearance of dihydrosafrole and its metabolites from both the ethmoid (olfactory) and maxillary (respiratory) turbinate regions of Beagle dogs and Cynomolgus monkeys was examined. Nasopharyngeal mucus was collected at frequent intervals during periodic instillation of dihydrosafrole (and, for the dogs, 24 h after instillation). Blood, urine and feces were collected to examine dihydrosafrole clearance from the nose during instillations and up to 48 h after completion of the nasal instillations of [3H]dihydrosafrole. Analysis of mucus for dihydrosafrole metabolites was by HPLC. Most of the recovered radioactivity was in urine and blood samples over the first 24 h. Radioactivity was recovered from the nasopharyngeal mucus in both organic extractable and water soluble forms. HPLC of the organic extracts demonstrated that [3H]dihydrosafrole instilled in either turbinate region was metabolized to 2-methoxy-4-propylphenol, 2-methoxy-4-propenylphenol and 1-(3,4-methylenedioxyphenyl)propan-1-ol. A number of minor metabolites were produced in both species. One mucus sample from an ethmoid-instilled dog contained 1-(3,4-methylenedioxyphenyl)propene (isosafrole) as a metabolite. Results from this study indicate that interspecies, inter-individual, and inter-regional differences occur in the metabolism of nasally deposited dihydrosafrole in monkeys and dogs.

Mucociliary clearance and particle retention in the maxillary and ethmoid turbinate regions of beagle dogs.

In this study, the retention and clearance of particles instilled onto the epithelium at two sites in the nasal cavity were examined. Polystyrene microspheres (3 micron geometric diameter) were labeled with 141Ce or 85Sr and instilled simultaneously on the maxillary and ethmoid turbinates of beagle dogs. The retention and clearance patterns of the microspheres were followed for 30 d after instillation. Tissue samples, excreta content, and autoradiography of the radiolabels provided the basis for defining the fate of the microspheres or the radiolabels dissolved from the microspheres. Early nasal mucus velocity was significantly faster (p less than 0.05) from the maxillary turbinate region (2.5 +/- 0.7 mm/min, mean +/- SE) than from the ethmoid turbinate region (0.6 +/- 0.4 mm/min). Retention at both instillation sites at 30 d after instillation was approximately 0.1% of the amount initially instilled. Radioactivity was excreted primarily via the feces during the first few days. Radiolabel measured in urine and tissues other than turbinates was small (less than 0.05% of the initial burden), indicating minimal dissolution of the radiolabel from the particles. Autoradiographs of turbinate tissue revealed particles sporadically located in the epithelial submucosa. From these data, it was concluded that a significant difference in early clearance for particles exists between the ethmoid and maxillary turbinates, but there was no difference in the fraction of particles retained in these two areas for long periods of time.