Exposure to MMVF in residential and commercial buildings: A literature review and quantitative synthesis

Man-made vitreous fibers (MMVF) are a class of inorganic fibrous materials that include glass and mineral wools, continuous glass filaments, and refractory ceramic fibers valued for their insulative properties in high temperature applications. Potential health effects from occupational exposure to MMVF have been investigated since the 1970s, with focus on incidence of respiratory tract cancer among MMVF-exposed production workers. The general population may experience exposure to MMVF in residential and/or commercial buildings due to deterioration, construction, or other disruption of materials containing these fibers. Numerous studies have characterized potential exposures that may occur during material disruption or installation; however, fewer have aimed to measure background MMVF concentrations in residential and commercial spaces (i.e., non-production settings) to which the general population may be exposed. In this study, we reviewed and synthesized peer-reviewed studies that evaluated respirable MMVF exposure levels in non-production, indoor environments. Among studies that analyzed airborne respirable MMVF concentrations, 110-fold and 1.5-fold differences in estimated concentrations were observed for those studies utilizing phase contrast optical microscopy (PCOM) versus transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. A positive correlation was observed between respirable air concentrations of MMVF and total surface concentrations of MMVF in seldom-cleaned areas. Ultimately, available evidence suggests that both ambient air and surface concentrations of MMVF in indoor environments are consistently lower than exposure limits developed to prevent negative health outcomes among sensitive populations.

Strategies for refinement of occupational inhalation exposure evaluation in the EPA TSCA risk evaluation process

The focus on occupational exposures in the first published risk evaluations of existing chemicals by the Environmental Protection Agency (EPA) under the amended Toxic Substances Control Act (TSCA) puts a welcome spotlight on protecting the health of workers in the United States. Because new, fit-for-purpose occupational exposure assessment methodologies were developed by EPA, the objective of this analysis was to evaluate these methodologies in light of other existing occupational risk assessment frameworks. We focused our analysis on three chlorinated chemicals (methylene chloride, carbon tetrachloride, perchloroethylene). The EPA's methods were evaluated relative to peer-reviewed and professional organizations' guidelines for conducting site- and facility-based exposure assessment. Analyses of several key phases in the EPA approach were conducted to evaluate the effect of alternative approaches on exposure estimates. The revised exposure estimates using these alternative approaches yielded substantially different exposure estimates from those in the TSCA risk evaluations for these chemicals. The results also demonstrated the importance of utilizing a tiered approach to exposure estimation that includes collecting qualitative data, defining similar exposure groups, and integrating well-parameterized models with empirical data. These approaches aid in preventing mischaracterization of exposures and generating exposure estimates representative of current industrial practices. Collaboration among industry, EPA, and other government agencies to develop a harmonized approach to exposure assessment would improve the methodological rigor of, and increase stakeholder confidence in, the results of TSCA risk evaluations.

Drainage of anorectal abscesses in the operating room is associated with a decreased risk of abscess recurrence and fistula formation

BACKGROUND

Timely incision and drainage (I&D) is first line management for anorectal abscesses. We aimed to define current practices in anorectal abscess management and identify factors associated with abscess recurrence and fistula formation.

METHODS

Index episodes of anorectal abscesses treated with I&D in 2014-2018 at a multi-hospital healthcare system were included. Association with one-year abscess recurrence or fistula formation was evaluated using Cox proportional hazard regression. Fistulae were captured only among patients without fistulae at the index operation.

RESULTS

A total of 458 patients met study criteria. One-year rate of abscess recurrence or fistula formation was 20.3%. When compared to bedside procedures, drainage in the operating room was associated with a reduced risk of either recurrence or fistula formation (aHR 0.20 [95%CI 0.114-0.367]).

CONCLUSIONS

Improved exposure and patient comfort in the operating room may allow more complete drainage contributing to decreased rates of abscess recurrence or fistula formation.

Analysis of dermal exposure assessment in the US Environmental Protection Agency Toxic Substances Control Act risk evaluations of chemical manufacturing

The United States Environmental Protection Agency (EPA) regulates chemical manufacture, import, processing, distribution, use, and disposal under the 2016 amended Toxic Substances Control Act (TSCA) for the purposes of protecting the public and sensitive populations-including workers-from chemical exposure risk. The publication of several TSCA risk evaluations provided a unique opportunity to evaluate the evolving regulatory approach for assessing the dermal exposure pathway in occupational settings. In this analysis, the occupational dermal exposure assessment methods employed in several TSCA risk evaluations were assessed. Specifically, a methodology review was conducted for the occupational dermal scenarios of manufacturing and feedstock use in the risk evaluations of three chlorinated organic chemicals: trichloroethylene, carbon tetrachloride, and perchloroethylene. Additionally, alternative exposure estimates were generated using the exposure model IH SkinPerm^TM. The review and alternative exposure analyses indicate that the current TSCA modeling approach may generate total dermal absorbed doses for chlorinated chemical manufacturing and feedstock use scenarios that are 2- to 20-fold higher than those generated by IH SkinPerm. Best-practice recommendations developed in the methodology review support a tiered, integrated approach to dermal exposure assessment that emphasizes collecting qualitative data; employing validated, peer-reviewed models that align with current industrial practices; and gathering empirical sampling data where needed. Collaboration among industry, EPA, and other stakeholders to share information and develop a standard approach to exposure assessment under TSCA would improve the methodological rigor of, and increase confidence in, the risk evaluation results.

Assessment of formaldehyde exposures under contemporary embalming conditions in U.S. funeral homes

The funeral service profession has used formaldehyde-containing embalming solutions for the preparation of decedents since the early 1900s. The available literature regarding funeral director exposure to formaldehyde largely consists of data collected prior to 2000, with most studies reporting task-length exposure concentrations rather than full-shift time-weighted average concentrations. As formaldehyde undergoes review in the U.S. Environmental Protection Agency Toxic Substances Control Act (TSCA) risk evaluation process, accurately characterizing long-term exposure potential in this profession is critical. This study presents passive badge sampling and air change rate measurement results conducted at 13 funeral home locations across the United States. Full-shift (approximately 8-hr) samples were collected on one embalmer per day in each funeral home and on one occupational non-user (ONU), e.g., a receptionist. Additionally, task-length samples were collected during each embalming that occurred during the shift, were one to occur. Full-shift concentrations ranged from 0.007 to 1.1 ppm and 0.007 to 0.042 ppm for embalmers and ONUs, respectively. Task-length formaldehyde concentrations ranged from 0.058 to 1.4 ppm, with the average embalming taking 72.8 min to complete. Air change rates in the preparation rooms ranged from 2.8 to 28.3 air changes per hour; however, no correlation between task-length formaldehyde concentrations and air change rate was observed. Following empirical data collection, a Monte Carlo analysis of estimated annual 8-hr time-weighted average (TWA) exposure was conducted to determine the potential exposure distribution for embalmers employed at private funeral homes. Inputs to the simulation were derived from responses to a National Funeral Directors Association survey and from empirical measurements collected during the study. With respect to the reconstructed 8-hr TWAs, the median 8-hr TWA was 0.037 ppm, with 93.6% of the predicted concentrations below 0.1 ppm. This study provides a robust characterization of contemporary formaldehyde exposures in the funeral service profession. Further, it provides a strategy for interpreting the results along with surveyed responses regarding embalming frequency to better inform risks associated with formaldehyde exposure in this profession.

Isolated eyelid edema in Melkersson-Rosenthal syndrome: a case series

PURPOSE

To report the clinicopathologic features of a series of patients with Melkersson-Rosenthal syndrome (MRS).

METHODS

Patients in this clinicopathological case series were identified through retrospective review. Five Caucasian patients (2 women and 3 men; age range, 46 to 73 years) with isolated eyelid swelling presented over an 11-month period to two Canadian tertiary Oculoplastic referral centres. All underwent clinical examination and had tissue biopsies.

RESULTS

The patients presented with non-pitting, non-pruritic, painless and recurrent eyelid swelling. None had evidence of cranial nerve palsy or fissured tongue. The duration of symptoms before referral was between 1-5 years. Histopathological examination showed granulomatous inflammation in four patients. Granulomatous folliculitis was a novel finding in three patients.

CONCLUSIONS

Monosymptomatic patients with MRS require a high index of suspicion. Histopathological confirmation is vital for the diagnosis.

Off-Axis Growth of Y1Ba2Cu3O7-y on Different Substrates

Films of Y1Ba2Cu3O7-y have been grown by off-axis DC sputtering onto substrates of (100) SrTiO3. LaAlO, LaGaO3, Yttria-stabilized Zirconia, and MgO. Our best films, grown on SrTiO3 substrates at a temperature of 650°C and a sputtering pressure of 100 mTorr (consisting of 80 mTorr Ar and 20 mTorr O2) have room temperature resistivities of 280 μΩ-cm, an inductive Tcof 88 K and an inductive Jc 'Sof∼ 2.6 × 106 A/cm2 at 77 K and 3.9 × 107 A/cm2at 4.2 K. Films grown on YSZ tend to have higher resistivities (∼ 600 μΩ-cm) but still have Tc's of 86 K and Jc's of - 106 A/cm2 at 77 K. Films down to 550 Å still have Tc's of 86 K and Jc's at 77 K > 106 A/cm2. Films grown at lower temperatures (600°C) on S1TiO3 begin to show a-axis growth, but the superconducting properties deteriorate.

Improved soil fumigation by Telone C35 using carbonation

Soil fumigation to control pests and pathogens is an important part of current agricultural practice. A reduction in fumigant emissions is required to ensure worker safety and environment health. A field trial in Florida was conducted to investigate whether carbonating Telone C35™ ((Z)- and (E)-1,3-dichloropropene with 35 % chloropicrin) would improve the delivery of the fumigant to such an extent that the application rate could be decreased without sacrificing efficacy. All treatments were carried out in three replications in a complete block design. The use of carbon dioxide (CO(2)) to carbonate and pressurize Telone C35 provided quicker and deeper distribution initially compared to application by nitrogen gas (N(2)) pressurization. The deeper distribution of Telone C35 components found with CO(2) application may have lowered the initial concentration of Telone C35, but it did not appreciably alter the disappearance rate of the three chemicals, chloropicrin, (Z)- and (E)-1,3-dichloropropene. The faster vertical distribution within the bedded soil of the Telone C35 by CO(2) did enhance volatilization of the active ingredients into the atmosphere compared to volatilization of similar reduced rate applied by N(2) pressurization. However, the cumulative amount volatilized from the carbonated fumigant beds at 75 % application rate was lower than the cumulative amount emitted by full rate of Telone C35 using N(2). The efficacy of the carbonated Telone C35 at a lower application rate was statistically equivalent to that of non-carbonated fumigant using N(2) pressurized injection at a higher application rate, based on weed enumeration and the root-knot nematode galling index.

Effects of application methods and plastic covers on distribution of cis- and trans-1,3-dichloropropene and chloropicrin in root zone

This study examined the effects of three application methods (chisel injection, Avenger coulter injection, and drip irrigation) and two plastic films (polyethylene film [PE] and virtually impermeable film [VIF]) on distribution of cis- and trans- 1,3-dichloropropene (1,3-D) and chloropicrin (CP) in a Florida sandy soil after application of Telone C35 or Telone In-Line. Regardless of application method, VIF retained greater amounts of cis- and trans-1,3-D and CP in the root zone with longer residential time than PE. There was better retention of the three compounds in the root zone when applied with the Avenger coulter injection rig than chisel injection, especially in combination with VIF. Distribution of the three compounds in the root zone was less predictable when applied by drip irrigation. Following drip irrigation, more than 50% of the three compounds in the PE and VIF-covered beds was found near the end of the drip tapes in one experiment, whereas the distribution was much more uniform in the root zone in a second experiment. Among the three biologically active compounds, CP disappeared from the root zone more rapidly than cis- and trans-1,3-D, especially in the PE-covered beds.

Pulque intake during pregnancy and lactation in rural Mexico: alcohol and child growth from 1 to 57 months

OBJECTIVE

To examine maternal intake of a mildly alcoholic beverage (pulque) during pregnancy and lactation, and its potential effect on postpartum child growth and attained size.

DESIGN

A prospective cohort study that followed mothers (during pregnancy and lactation) and their offspring (from birth to approximately 57 months of age).

SETTING

Six villages in rural, central Mexico.

SUBJECTS

Subjects are 58 mother-child pairs. Pulque intake was measured as part of a dietary assessment that was conducted for 2days/month during pregnancy and early lactation.

RESULTS

Most mothers consumed pulque during pregnancy (69.0%) and lactation (72.4%). Among pulque drinkers, the average ethanol intake was 125.1 g/week during pregnancy and 113.8 g/week during lactation. Greater pulque intake during lactation, independent of intake during pregnancy, was associated with slower weight and linear growth from 1 to 57 months, and smaller attained size at 57 months. Low-to-moderate pulque intake during pregnancy, in comparison to either nonconsumption or heavy intake, was also associated with greater stature at 57 months.

CONCLUSIONS

Pulque intake during lactation may have adversely influenced postnatal growth in this population. Public health interventions are urgently needed in Mexico to reduce heavy intake of pulque by pregnant and lactating women, and to replace intake with foods that provide the vitamins and minerals present in the traditional alcoholic beverage.

Low erythrocyte folate, but not plasma vitamin B-12 or homocysteine,is associated with dementia in elderly Latinos

The relationship between B vitamin status and cognitive function has been of interest for many years. There is evidence of relationships between intake and status of folate and vitamin B-12 with neurological, cognitive, and memory impairment, but results have been inconsistent. Plasma B-12, erythrocyte folate, methylmalonic acid,and homocysteine were evaluated as predictors of cognitive function in a large population based sample of Latino elderly living in the Sacramento, California region. The hypothesis tested was that low folate and/or B-12 status predicts cognitive function impairment and dementia. Logistic regression was used to examine the differences in B-vitamin status by cognitive function category. Erythrocyte folate was related to dementia after controlling for age, gender, education, income, diabetes diagnosis, serum creatinine, and depressive symptoms. The highest prevalence of low erythrocyte folate occurred in the Dementia group and was significantly higher than in the Normal group. Plasma B-12, MMA, Hcy, and prevalence of a normal values for these variables, were not significantly different among the cognitive function classes. We conclude that folate status is associated with dementia but that more research is needed on the relationship between vitaminB-12 status, Hcy and cognitive function to explore possible associations with these parameters.

Persistence, distribution, and emission of Telone C35 injected into a Florida sandy soil as affected by moisture, organic matter, and plastic film cover

With the phase-out of methyl bromide scheduled for 2005, alternative fumigants are being sought. This study of Telone C35, a mixture of (Z)- and (E)-1,3-dichloropropene (1,3-D) with chloropicirin (CP), focuses on its emissions, distribution, and persistence in Florida sandy soil in microplots with different soil-water and organic matter carbon (C) content with and without two different plastic film mulches. The addition of CP did not affect the physical behavior of the isomers of 1,3-D. Slower subsurface dispersion and longer residence time of the mixed fumigant occurred at higher water content. An increase in the percent organic carbon in the soil led to a more rapid decrease for chloropicirin than for 1,3-dichloropene isomers. The use of a virtually impermeable film (VIF) for soil cover provided a more even distribution and longer persistence under all the conditions studied in comparison to polyethylene (PE) film cover or no cover. The conditions of near field capacity water content, low organic matter, and a virtually impermeable film cover yielded optimum conditions for the distribution, emission control, and persistence of Telone C35 in a Florida sandy soil.

Efficacy of 1,3-dichloropropene in soil amended with compost and unamended soil

1,3-Dichloropropene (1,3-D) is a likely alternative soil fumigant for methyl bromide. The objective was to determine root-knot nematode, Meloidogyne incognita, survival in microplots after exposure to 1,3-D for various periods of time in soil that have previously been amended with compost. The treatments were 1,3-D applied broadcast at 112 liters/ha and untreated controls in both compost-amended and unamended soil. Soil samples were collected from each microplot at 6, 24, 48, 72, and 96 hours after fumigation at three depths (0-15, 15-30, and 30-45 cm). One week after fumigation, six tomato seedlings were transplanted into each microplot and root galling was recorded 6 weeks later. Plants grown in fumigated compost-amended soil had more galls than plants from fumigated unamended soil at P </= 0.1. Gall indices from roots in fumigated soil amended with compost were not different from nonfumigated controls. Based on soil bioassays, the number of galls decreased with increasing time after fumigation in both compost-amended and unamended soil at 0-to-15 and 15-to-30 cm depths, but not at 30 to 45 cm deep. Higher soil water content due to the elevated levels of organic matter in the soil at these depths may have interfered with 1,3-D movement, thus reducing its efficacy.

Maternal consumption of pulque, a traditional central Mexican alcoholic beverage: relationships to infant growth and development

OBJECTIVES

To document the consumption during pregnancy of pulque, a traditional central Mexican alcoholic beverage, and its relationship to subsequent infant size, physical growth and performance on the Bayley Scales of Infant Development.

DESIGN

Prospective cohort study.

SETTING

Six villages in rural, central Mexico in 1984-1985.

SUBJECTS

Seventy mother-infant pairs.

RESULTS

Most women (72.9%) consumed pulque during pregnancy, and 28.6% consumed more than 150 g ethanol week(-1) from the beverage. Individuals who consumed pulque showed no compensating decrease in energy obtained from other foods. Pulque consumption possessed curvilinear relationships with both infant length (at 1 and 6 months) and Bayley mental performance (at 6 months). Heavy pulque intakes were associated with smaller infant size and poorer mental performance. In modest quantities, pulque consumption may have been beneficial due to its micronutrient content.

CONCLUSIONS

Intakes of alcohol from pulque were common among pregnant women in these rural, central Mexican villages. Given current scientific knowledge of the adverse effects of ethanol on foetal development, public health interventions are needed to reduce heavy pulque consumption during pregnancy in some areas of rural Mexico.

Evaluation of validity of items for a food behavior checklist

OBJECTIVES

To evaluate the validity of food behavior items, using a biological measure (serum carotenoids) as the criterion for validity of fruit and vegetable intake, and the results from multiple 24-hour recalls to test convergent validity with nutrient intake.

DESIGN

Participants responded to 39 food-behavior questions and later completed three 1-day dietary recalls. Serum carotenoid levels were determined for a 59% randomly selected subsample.

SUBJECTS/SETTING

A convenience sample of 100 English-speaking, low-income women participating in a Food Stamp Nutrition Education Program in 8 California counties. Statistical analyses Spearman correlation coefficients were calculated between responses to the food behavior items and (a) serum carotenoid levels and (b) mean nutrient intakes from the 24-hour recalls. Cronbach's coefficient alpha was determined for items within broad food behavior topics.

RESULTS

Responses to 10 food behavior items were significantly correlated with serum carotenoid levels (correlations greater than 0.45 were found for choosing low-fat foods and a self-evaluation of overall dietary quality). An additional 12 items showed hypothesized associations with the 24-hour recall data (with a maximum correlation 0.50 for number of eggs per week and dietary cholesterol). Cronbach's coefficient alpha ranged from 0.28 (for 5 fat and cholesterol items) to 0.79 (for 9 fruit and vegetable items).

APPLICATIONS/CONCLUSIONS

Nutrition professionals can use these methods to validate items for food behavior checklists for specific populations. The items described here may be useful when designing instruments to administer to low-income women in a community setting.

Nutrition: a reservoir for integrative science

In the last twenty years, powerful new molecular techniques were introduced that made it possible to advance knowledge in human biology using a reductionist approach. Now, the need for scientists to deal with complexity should drive a movement toward an integrationist approach to science. We propose that nutritional science is one of the best reservoirs for this approach. The American Society for Nutritional Sciences can play an important role by developing and delivering a cogent message that convinces the scientific establishment that nutrition fills this valuable niche. The society must develop a comprehensive strategy to develop our image as the reservoir for life sciences integration. Our efforts can start with our national meeting and publications, with the research initiatives for which we advocate, with our graduate training programs and with the public relations image we project for ourselves. Defining the image and future directions of nutrition as the discipline that can integrate scientific knowledge from the cell and molecule to the whole body and beyond to populations can be the most important task that our society undertakes. If we do not effectively meet this challenge, a golden opportunity will pass to others and nutritional scientists will be left to follow them.

RNA localization and germ cell determination in Xenopus

In many organisms the proper development of the embryo depends on the asymmetrical distribution of maternal RNAs and proteins in the egg. Although the Xenopus oocyte is radially symmetrical it contains distinct populations of maternal RNAs that are localized either in the animal or vegetal pole. The process of localization of RNAs in Xenopus oocytes occurs during the long period of oocyte differentiation and growth that is accompanied by the elaboration of oocyte polarity. Some of the vegetally localized RNAs, such as Vg1, VegT, and Xwnt11, are involved in axial patterning and germ layer specification. Others, such as Xdazl and Xcat2, which are located in the germ plasm, are likely to play a role in the specification of germ cell fate. We will discuss the different aspects of RNA localization in Xenopus in the context of the differentiation of the germ cells and the development of the oocyte polarity.

Biological mechanisms that might underlie iron's effects on fetal growth and preterm birth

A negative association between anemia and duration of gestation and low birth weight has been reported in the majority of studies, although a causal link remains to be proven. This paper explores potential biological mechanisms that might explain how anemia, iron deficiency or both could cause low birth weight and preterm delivery. The risk factors for preterm delivery and intrauterine growth retardation are quite similar, although relatively little is understood about the influence of maternal nutritional status on risk of preterm delivery. Several potential biological mechanisms were identified through which anemia or iron deficiency could affect pregnancy outcome. Anemia (by causing hypoxia) and iron deficiency (by increasing serum norepinephrine concentrations) can induce maternal and fetal stress, which stimulates the synthesis of corticotropin-releasing hormone (CRH). Elevated CRH concentrations are a major risk factor for preterm labor, pregnancy-induced hypertension and eclampsia, and premature rupture of the membranes. CRH also increases fetal cortisol production, and cortisol may inhibit longitudinal growth of the fetus. An alternative mechanism could be that iron deficiency increases oxidative damage to erythrocytes and the fetoplacental unit. Iron deficiency may also increase the risk of maternal infections, which can stimulate the production of CRH and are a major risk factor for preterm delivery. It would be useful to explore these potential biological mechanisms in randomized, controlled iron supplementation trials in anemic and iron-deficient pregnant women.

Discrete periodic melting point observations for nanostructure ensembles

We report a study of the thermodynamic properties of indium clusters on a SiN (x) surface during the early stages of thin film growth using a sensitive nanocalorimetry technique. The measurements reveal the presence of abnormal discontinuities in the heat of melting below 100 degrees C. These discontinuities, for which temperature separation corresponds to a spatial periodicity equal to the thickness of an indium monolayer, are found to be related to the atomic "magic numbers," i.e., the number of atoms necessary to form a complete shell of atoms at particle surface.

Lack of hemoglobin response to iron supplementation in anemic mexican preschoolers with multiple micronutrient deficiencies

BACKGROUND

In developing countries, incomplete resolution of anemia with iron supplementation is often attributed to poor compliance or inadequate duration of supplementation, but it could result from deficiencies of other micronutrients.

OBJECTIVE

Our objective was to assess children's hematologic response to supervised, long-term iron supplementation and the relation of this response to other micronutrient deficiencies, anthropometry, morbidity, and usual dietary intake.

DESIGN

Rural Mexican children aged 18-36 mo (n = 219) were supplemented for 12 mo with either 20 mg Fe, 20 mg Zn, both iron and zinc, or placebo. Children were categorized as iron-unsupplemented (IUS; n = 109) or iron supplemented (IS; n = 108). Hemoglobin, hematocrit, mean corpuscular volume, mean cell hemoglobin, plasma concentrations of micronutrients that can affect hematopoiesis, anthropometry, and diet were assessed at 0, 6, and 12 mo; morbidity was assessed biweekly.

RESULTS

At baseline, 70% of children had low hemoglobin (</=115 g/L), 60% had low hematocrit, 48% were ferritin deficient, 10% had deficient and 33% had low plasma vitamin B-12 concentrations, 29% had deficient vitamin A concentrations, and 70% had deficient vitamin E concentrations. Iron supplementation increased ferritin from 11 +/- 14 microg/L at baseline to 31 +/- 18 microg/L after 6 mo (P < 0.001) and 41 +/- 17 microg/L after 12 mo. However, anemia persisted in 30% and 31% of supplemented children at 6 and 12 mo, respectively, and was not significantly different between the IUS and IS groups at 12 mo. Initial plasma vitamin B-12, height-for-age, and dietary quality predicted the hematopoietic response to iron.

CONCLUSION

Lack of hemoglobin response to iron was associated with indicators of chronic undernutrition and multiple micronutrient deficiencies.

In vitro and in vivo macrophage function can occur independently of SLP-76

Expression of SH2 domain-containing leukocyte-specific phosphoprotein of 76 kDa (SLP-76), a hematopoietic cell-specific adapter protein, is required to couple Syk family tyrosine kinase activation to downstream mediators such as phospholipase C (PLC)-gamma following TCR, platelet collagen receptor and mast cell Fc epsilon R stimulation. In addition to T cells, mast cells and platelets, SLP-76 is expressed in monocytes and macrophages. To determine the role of SLP-76 in Fc gamma R-stimulated signaling pathways in macrophages, we examined cultured bone marrow-derived macrophages (BMM) from SLP-76(-/-) and wild-type mice. In this study, we show that Fc gamma R cross-linking rapidly induces tyrosine phosphorylation of SLP-76 in wild-type BMM. Surprisingly, however, BMM from SLP-76(-/-) mice activate ERK2 and phosphorylate PLC-gamma 2 following Fc gamma R ligation. Furthermore, SLP-76(-/-) BMM display normal Fc gamma R-dependent phagocytic function and reactive oxygen intermediate production. SLP-76(-/-) and SLP-76(+/+) BMM secrete comparable levels of IL-12 in response to lipopolysaccharide and IFN-gamma. To examine macrophage function in vivo, SLP-76(-/-) mice were challenged i.v. with Listeria monocytogenes. SLP-76(-/-) mice survive and efficiently contain the acute phase of infection similar to wild-type mice but exhibit a stable chronic infection attributed to the lack of mature T cells. These data show that, although SLP-76 is required to couple Syk family PTK activity to downstream mediators and effector functions in Fc gamma R-induced pathways in some cell types, activation of Fc gamma R-dependent pathways occurs independently of SLP-76 in BM

Iron absorption from ferrous bisglycinate and ferric trisglycinate in whole maize is regulated by iron status

BACKGROUND

There is a need to determine whether iron absorption from iron amino acid chelates is protected from inhibition by dietary phytate and regulated normally by iron status.

OBJECTIVE

The objective of this study was to compare iron absorption from ferrous sulfate, ferrous bisglycinate, and ferric trisglycinate in whole-maize meal; to determine whether iron from ferrous bisglycinate and ferrous sulfate exchanges in the intestinal pool; and to assess iron absorption from ferrous bisglycinate and ferric trisglycinate over a range of iron statuses.

DESIGN

In study 1A, 10 iron-sufficient men consumed ferrous sulfate-fortified whole-maize meal porridge equilibrated with (59)Fe-sulfate on day 1 and (55)Fe-bisglycinate on day 2. In study 1B, these volunteers consumed ferrous sulfate-fortified porridge equilibrated with (59)Fe-sulfate and (55)Fe-bisglycinate simultaneously. In studies 2A and 2B, iron absorption from 3 mg Fe as (59)Fe-ascorbate, (55)Fe-bisglycinate, or (59)Fe-trisglycinate in water and in porridge was compared in 23 subjects with a range of iron statuses. Iron absorption was determined from blood radioactivity on day 16.

RESULTS

In study 1A, geometric mean iron absorption from ferrous bisglycinate was 6.0% (range: 2.6-13.6%), 4 times higher than that from ferrous sulfate (1. 7%; range: 1.0-3.3%; P < 0.05). In study 1B, absorption from neither source was different from that in study 1A. In studies 2A and 2B, absorption from all sources was strongly inversely related to serum ferritin, with geometric means of 32.5% (iron ascorbate), 9.1% (bisglycinate), and 15.3% (trisglycinate). Iron from ferric trisglycinate was poorly absorbed (2.3%; range: 0.5-9.2%) from maize.

CONCLUSION

In whole-maize meal, iron from ferrous bisglycinate is better absorbed than is iron from ferrous sulfate and does not exchange with iron from maize or ferrous sulfate in the intestinal pool. Absorption of iron from bisglycinate and trisglycinate is regulated normally by iron status.

Anemia and iron deficiency: effects on pregnancy outcome

This article reviews current knowledge of the effects of maternal anemia and iron deficiency on pregnancy outcome. A considerable amount of information remains to be learned about the benefits of maternal iron supplementation on the health and iron status of the mother and her child during pregnancy and postpartum. Current knowledge indicates that iron deficiency anemia in pregnancy is a risk factor for preterm delivery and subsequent low birth weight, and possibly for inferior neonatal health. Data are inadequate to determine the extent to which maternal anemia might contribute to maternal mortality. Even for women who enter pregnancy with reasonable iron stores, iron supplements improve iron status during pregnancy and for a considerable length of time postpartum, thus providing some protection against iron deficiency in the subsequent pregnancy. Mounting evidence indicates that maternal iron deficiency in pregnancy reduces fetal iron stores, perhaps well into the first year of life. This deserves further exploration because of the tendency of infants to develop iron deficiency anemia and because of the documented adverse consequences of this condition on infant development. The weight of evidence supports the advisability of routine iron supplementation during pregnancy.

Iron and zinc supplementation improves indicators of vitamin A status of Mexican preschoolers

BACKGROUND

The coexistence of multiple micronutrient deficiencies is a widespread public health problem in many regions of the world. Interactions between zinc deficiency and vitamin A metabolism have been reported but no longitudinal studies have evaluated the effect of iron deficiency on vitamin A.

OBJECTIVE

The objective of this study was to investigate the effect of supplementation with iron, zinc, or both on vitamin A and its metabolically related proteins retinol binding protein (RBP) and transthyretin.

DESIGN

The study was a longitudinal, double-blind, placebo-controlled trial in which 219 rural Mexican children aged 18-36 mo were randomly assigned to receive 20 mg Zn/d, 20 mg Fe/d, 20 mg Zn/d plus 20 mg Fe/d, or placebo.

RESULTS

Six months after supplementation, plasma retinol increased in all supplemented groups. Compared with placebo, zinc supplementation was associated with significantly higher plasma retinol and transthyretin but the increase in RBP was not significant. Iron supplementation significantly increased plasma retinol, RBP, and transthyretin. Supplementation with zinc plus iron significantly increased plasma retinol but not RBP or transthyretin. Children deficient in zinc, iron, or vitamin A (as indicated by nutrient plasma concentration) at the beginning of the study had a significantly greater increase in retinol than did children with adequate nutrient status.

CONCLUSIONS

Supplementation with zinc, iron, or both improved indicators of vitamin A status. The results of this study agree with previous observations of a metabolic interaction between zinc and vitamin A and suggest an interaction between iron and vitamin A metabolism.

Intervention within days for some orbital floor fractures: the white-eyed blowout

Management of blowout fractures involving the orbital floor has been controversial over the past several decades. One school of thought recommends conservative treatment for 4 to 6 months while another recommends a 'wait and watch' period of 2 weeks before intervention. The authors have encountered a group of patients with such fractures, commonly children (less than 16 years of age), who have sustained a blow to the periocular area, yet have marked motility restrictions in up and down gaze, minimal soft tissue signs of trauma, lack of enophthalmos, and very minimal evidence of floor disruption on radiologic exam. A 2-week waiting period has been found to be of little benefit in these persons and possibly harmful to their motility. We advocate surgery within the first few days after injury as it may help to avoid permanent motility restriction. The authors have termed this entity 'the white-eyed blowout fracture.'

Zinc and micronutrient supplements for children

Provision of zinc supplements to children should be considered when their usual diet is low in absorbable zinc; severe stunting, low plasma zinc, or both; or persistent diarrhea. Inadequate zinc intakes are highly prevalent in developing countries, especially during the period of complementary feeding when zinc requirements are high and breast milk contributes little. To date, systematic evaluation of the acceptability of different zinc salts used as supplements is lacking. Some zinc salts are unpalatable and cause problems, such as nausea, at higher doses. Zinc carbonate and oxide are insoluble and poorly absorbed. Little information on the bioavailability of different zinc supplements in the presence of dietary inhibitors of zinc absorption exists. More information is needed on the quantity and frequency of dosing. Consideration should be given to the routine inclusion of zinc in iron supplements provided to children and to the simultaneous inclusion of other micronutrients in zinc supplements.

Spot ferritin assay for serum samples dried on filter paper

A spot method was developed for analyzing ferritin from 20-microL serum samples (n = 71) that were spotted and dried on filter paper and stored frozen (2 d). Spot samples were thawed, incubated in a buffer containing cellulase, and centrifuged and the supernate assayed for ferritin by a commercial radioimmunoassay. The geometric means (+/- 1 SD) for ferritin analyzed with the spot and traditional methods were 49.4 (range: 14.9-164.0) and 47.5 (range: 14.4-156.0) micrograms/L, respectively. The two methods correlated strongly (r = 0.98, P = 0.0001). Storage of spot samples (n = 31) under various conditions (at room temperature, refrigerated, or frozen for 2 wk, or at room temperature for 4 wk) in airtight bags before analysis yielded ferritin values that were not significantly different from those obtained by the traditional method. Ferritin values from spotted samples stored at room temperature for 4 wk before being analyzed were only 2.2 micrograms/L higher than those from samples analyzed by the traditional method. With iron depletion defined as a serum ferritin concentration < 15 micrograms/L, this method corresponded absolutely with the traditional method in classifying individuals as iron sufficient or deficient. Thus, the spot ferritin method (with samples stored at room temperature for 4 wk) offers a reliable, accurate, and practical tool for iron status assessment in field studies. Capillary blood can be sampled to avoid the costs and concerns associated with venipuncture and spotted serum samples can be stored at room temperature for > or = 4 wk, eliminating the need for freezing during storage and transportation.

Vitamin B-12 deficiency is very prevalent in lactating Guatemalan women and their infants at three months postpartum

Vitamin B-12 status was evaluated in 113 Guatemalan women and their infants at 3 mo of lactation. Plasma vitamin B-12 was deficient or low in 46.7% of the mothers, and holotranscobalamin II (holo TC II) concentrations were low in 32.3%, which may indicate vitamin B-12 malabsorption. Only 9% had deficient or low plasma folate. Breast milk vitamin B-12 was low in 31%, and negatively correlated with infant urinary methylmalonic acid (UMMA, r = -0.22, P < 0.05, n = 88); UMMA was elevated in 12.2% of the infants, indicating vitamin B-12 deficiency. Mothers of the infants with elevated UMMA had significantly lower concentrations of vitamin B-12 in their breast milk compared with mothers of infants with normal UMMA concentrations (410.7 +/- 247.7 vs. 705.3 +/- 487.5 pmol/L, P = 0.05, n = 87). Mean maternal dietary intake of vitamin B-12 was significantly correlated with plasma vitamin B-12 (r = 0.20, P = 0. 05, n = 94) and was the main determinant of plasma vitamin B-12 in a linear regression model. Determinants of maternal holo TC II concentrations included dietary intake of vitamin B-12 and Giardia lamblia infection. There were no statistically significant determinants of infant UMMA concentrations. We conclude that vitamin B-12 deficiency is highly prevalent in these lactating women and is associated with depletion of the vitamin in their infants. The cause of the maternal deficiency is unknown, but malabsorption exacerbated by low dietary intake of the vitamin is a possibility.

Examining the gender gap in nutrition: an example from rural Mexico

Gender differences in nutrient and food intake were examined in Mexican Nutrition CRSP (Collaborative Research Support Program) infants (N = 75), preschoolers (N = 80), and school children (N = 91). No significant gender differences in dietary quality or quantity were seen for infants and preschoolers. For school children, the contribution of various foods to total energy intake (dietary quality) was also quite similar for girls and boys. Equity in dietary quality remained even under conditions of economic and demographic stress. Nevertheless, school girls consumed significantly less energy per day than boys (-300 kcal/d or 1.3 mJ/d), and less of all micronutrients examined. Gender differences in estimated basal metabolic rates of school children were slight (-20 kcal/d), and body composition and size were similar. When energy intakes were expressed as a percent of estimated requirement (calculated from age, sex and weight using WHO/FAO/UNU equations), intakes were adequate and not significantly different between girls (mean = 111%) and boys (mean = 113%). Playground observations showed girls to be less active than boys, which may reflect both cultural and biological influences. Apparently due to this lower activity, school girls consumed less energy, and may have been at much higher risk than boys of micronutrient deficiency. The lower food intakes of girls did not appear to be due to purposeful dietary discrimination, but rather to culturally patterned sex roles involving lower activity.

Pregnancy and iron deficiency: unresolved issues

Iron deficiency and iron deficiency anemia are prevalent among pregnant women. The extent to which iron deficiency affects maternal and neonatal health is uncertain. Existing data suggest that maternal iron deficiency anemia may be associated with adverse outcomes, including preterm delivery and higher maternal mortality. Further research is needed on the maternal and neonatal benefits of iron supplementation during pregnancy.

Zinc supplementation reduced morbidity, but neither zinc nor iron supplementation affected growth or body composition of Mexican preschoolers

In rural Mexico and in many developing countries micronutrient deficiencies, growth stunting, and morbidity from infectious diseases are highly prevalent in young children. We assessed the extent to which growth stunting could be reversed and the number of infectious disease episodes reduced by zinc and/or iron supplementation. In a double-blind, randomized community trial 219 Mexican preschoolers were supplemented with either 20 mg Zn as zinc methionine, 20 mg Fe as ferrous sulfate, 20 mg Zn + 20 mg Fe, or a placebo. After 12 mo, plasma zinc increased significantly in the two zinc-treated groups, and plasma ferritin was significantly higher in the two iron-treated groups. There was no effect of treatments on growth velocity or body composition. Children in both zinc-supplemented groups had fewer episodes of disease (zinc alone, 3.9 +/- 0.3; zinc+iron, 3.7 +/- 0.4; placebo, 4.6 +/- 0.5; P < 0.03), including diarrhea (zinc alone, 0.7 +/- 0.1; zinc+iron, 0.8 +/- 0.1; placebo, 1.1 +/- 0.2; P < 0.01). Zinc and zinc+iron supplements reduced morbidity but had no effect on growth or body composition.

Determinants of body size perceptions and dieting behavior in a multiethnic group of hospital staff women

OBJECTIVE

This study was designed to identify determinants of body size perceptions and their relationship to dietary behavior in a multiethnic group of women.

DESIGN

A single interview consisting of the Massara and Stunkard body image cards (1979) and questionnaires on sociocultural background, anthropometry, and dieting history were administered to volunteers from the staff of a hospital.

SUBJECTS

The sample was a convenience sample of 186 women representing a range of staff positions recruited from Methodist Hospital in Brooklyn, NY; 174 completed the study. Data on 150 women are presented in this article.

RESULTS

Height and weight-for-height were stronger predictors of accuracy of perceived body size than ethnicity. Tall, slight women were more likely to overestimate and short, heavy women were more likely to underestimate actual body size. Ethnicity had an interactive effect with height as taller European Americans were more likely to perceive their body size as larger than actual compared with Afro-Caribbeans and African Americans. Women with a history of dieting were more likely to overestimate their size and to view it as different from what is perceived as attractive to others.

APPLICATIONS/CONCLUSIONS

Based on the results, we conclude that body size is a stronger predictor of accuracy of perceived body size than ethnicity; and dieters overestimate their body size and believe it to be heavier than their social group would prefer.

Vitamin B-12 deficiency and malabsorption are highly prevalent in rural Mexican communities

Vitamin B-12 status of rural Mexicans was evaluated in two studies, 6 y apart. In the first, a single blood sample was collected from children and adults, including pregnant and lactating women. Prevalence of deficient plasma vitamin B-12 values ranged from 19% to 41% among groups, but plasma folate status was normal in all individuals. Breast milk vitamin B-12 concentration was low in 62% of samples. The second study was conducted in 219 children aged 18-36 mo in five communities, whose prevalence of deficient and low plasma vitamin B-12 concentrations, respectively, was 8% and 33% on entry, 3% and 22% 6 mo later, and 7% and 29% 12 mo later. Prevalence of low holotranscobalamin II concentrations, indicating malabsorption of the vitamin, averaged 18-40% across the three same periods. Both vitamin B-12 status indicators differed significantly between communities. The widespread vitamin B-12 deficiency was probably caused by malabsorption, perhaps exacerbated by low dietary intake and, for young children, maternal depletion of the vitamin.

A role for MARCKS, the alpha isozyme of protein kinase C and myosin I in zymosan phagocytosis by macrophages

Myristoylated, alanine-rich C-kinase substrate (MARCKS) is a lipopolysaccharide-induced protein kinase C (PKC) substrate that has been proposed to regulate actin-membrane interactions, as well as actin structure at the membrane. We studied the distribution of MARCKS, the alpha isozyme of PKC (PKC alpha), and myosin I in lipopolysaccharide-treated peritoneal macrophages ingesting zymosan particles. MARCKS, PKC alpha, and myosin I colocalized with F-actin and talin in the cortical cytoplasm adjacent to forming phagocytic cups. After particle ingestion was completed, myosin I, F-actin, and talin were no longer enriched in the vicinity of the phagosome. By contrast, MARCKS and PKC alpha remained associated with the phagosome membrane until after acquisition of the lysosomal marker Lamp-1. Vinculin was not detected on phagosomes at any time point examined. Phagocytosis of zymosan was accompanied by rapid and sustained phosphorylation of MARCKS. Inhibitors of PKC reduced zymosan binding to the macrophage surface and blocked the focal accumulation of F-actin, talin, phosphotyrosine-containing proteins, MARCKS, and PKC alpha beneath attached particles. We propose that PKC-dependent phosphorylation is an early signal required for zymosan phagocytosis and that MARCKS and PKC alpha have a role in phagosome maturation. The colocalization of F-actin and MARCKS at the cytoplasmic face of the nascent phagosome reinforces the hypothesis that MARCKS regulates actin structure at the membrane. Our data also suggest that myosin I functions as a mechanical motor during particle uptake.

Vicryl-mesh wrap for the implantation of hydroxyapatite orbital implants: an animal model

OBJECTIVE

To evaluate host fibrovascularization of hydroxyapatite orbital implants wrapped in sclera or in Vicryl (polyglactin 910) mesh in a rabbit model.

NUMBERS

Eight adult New Zealand white rabbits that received hydroxyapatite orbital implants wrapped in homologous donor sclera (four animals) or Vicryl mesh (four animals).

INTERVENTIONS

The rabbits had one eye enucleated and then received a 12-mm hydroxyapatite implant wrapped in sclera or Vicryl mesh. Magnetic resonance imaging (MRI) and bone scintigraphy were done to assess host fibrovascularization of the implant 4, 8, 12 and 20 weeks after implantation. Two animals (one in each group) were killed at each of these times, and the implant was removed for histopathological examination.

MAIN OUTCOME MEASURES

Enhancement on MRI, uptake on bone scintigraphy, fibrovascularization seen on histopathological examination.

RESULTS

The degree of fibrovascularization was substantial in all the specimens but appeared greater in the Vicryl-mesh-wrapped implants in the first 12 weeks after implantation on both histopathological and MRI studies. At 20 weeks these findings were similar in the two groups. A granulomatous foreign-body giant-cell reaction to both the Vicryl mesh and the implant itself was present up to 8 weeks after implantation. Bone scans showed only grade 1+ activity in all the implants.

CONCLUSIONS

Host fibrovascularization in the rabbit appears to occur to a greater degree in Vicryl-mesh-wrapped hydroxyapatite implants than in those wrapped in donor sclera during the first 12 weeks after implantation. Vicryl mesh appears to be an acceptable alternative wrap for the hydroxyapatite implant, eliminating the need for donor sclera and its potential risks of transmissible diseases.

The use of Vicryl mesh (polyglactin 910) for implantation of hydroxyapatite orbital implants

Hydroxyapatite (HA) implants currently are most commonly wrapped in donor sclera before implantation to facilitate placement within the orbit and allow attachment of the extraocular muscles. Although the risk of acquiring a transmittable disease through donor sclera is extremely low, some individuals remain concerned about receiving nonautologous material. As an alternative to sclera, autologous temporalis fascia, or autologous fascia lata, we have been wrapping HA in "Vicryl mesh" before insertion into the orbit. The Vicryl mesh-wrapped implant goes into the socket readily, allows one to easily attach the extraocular muscles, and has no risk of transmittable disease. In addition, the Vicryl mesh is readily available at most hospitals and is dissolvable.

Malnutrition and human function: a comparison of conclusions from the INCAP and nutrition CRSP studies

The overall objective of both the Institute of Nutrition of Central America and Panama (INCAP) studies and the Nutrition Collaborative Research Support Program (CRSP) was to determine if marginal malnutrition affects human function. The conclusions from the two studies were consistent, notably that growth stunting occurs early in life and is accompanied by functional impairments. These consequences of early malnutrition persist later in life. The comparison of INCAP and Nutrition CRSP results also illustrates that the Guatemalan children were more malnourished and stunted than those in Kenya, Mexico or Egypt and that this greater degree of stunting occurs before 18 months of age. Even the Atole did not bring the average size of supplemented children in Guatemala up to those of the unsupplemented children in the CRSP populations. It is also likely that their functional potential was not realized fully by supplementation. The CRSP studies provide evidence of multiple micronutrient deficiencies associated with poor growth and function and it is probable that these associations exist in Guatemala as well. The overall conclusion is that our attention should be directed to determining the adequacy of micronutrient status in the perinatal period and to the development of approaches that prevent early growth failure.