Vitamin D (25OHD) Serum Seasonality in the United States

Background

Vitamin D is an important micronutrient for health. Hypovitaminosis D is thought to play a role in the seasonality of a number of diseases and adverse health conditions. To refine hypotheses about the links between vitamin D and seasonal diseases, good estimates of the cyclicality of serum vitamin D are necessary.

Objectives

The objective of this study is to describe quantitatively the cyclicality of 25-hydroxyvitamin D (25OHD) in the United States. We provide a statistical analysis with weekly time resolution, in comparison to the quarterly (winter/spring/summer/fall) estimates already in the literature.

Methods

We analyzed time series data on 25OHD, spanning 287 consecutive weeks. The pooled data set comes from 3.44 million serum samples from the United States. We statistically analyzed the proportion of sera that were vitamin D sufficient, defined as 25OHD ng/mL, as a function of date.

Results

In the United States, serum 25OHD follows a lagged pattern relative to the astronomical seasons, peaking in late summer (August) and troughing in late winter (February). Airmass, which is a function of solar altitude, fits the 25OHD data very well when lagged by 8 weeks.

Conclusions

Serum vitamin D levels can be modeled as a function of date, working through a double-log transformation of minimal solar airmass (easily calculated from solar altitude, retrievable from an online solar altitude/azimuth table).     

Plants of the Northeastern United States that produce cyanogenic compounds

We have surveyed the distribution of plants in the northeastern United States that contain cyanogenic compounds. Approximately 200 species of plants from 45 families are known to contain compounds capable of liberating hydrogen cyanide upon hydrolysis. These are primarily found in the Gramineae, Ranunculaceae and the Rosaceae. The chemical structures compounds of the cyanogens have been studied in only a small number of the species included, and investigation of the biology and chemistry of these plants should prove especially profitable.     

Evidence of susceptibility to morbillivirus infection in cetaceans from the United States

Cetacean morbilliviruses (CeMV) are viruses that can cause mass mortalities among various odontocete species. In this study levels of “herd” immunity in cetaceans from the U.S. coast are described from the distribution and prevalence of antibodies against morbilliviruses. Neutralizing antibody titers against dolphin morbillivirus (DMV), porpoise morbillivirus (PMV), phocine distemper (PDV), and canine distemper viruses (CDV) were measured. Positive samples had higher titers against the CeMV than against the other morbilliviruses tested, indicating that although PDV or CDV can be used to investigate exposure their use may result in a higher false negative rate. The results suggest that morbillivirus did not persist in coastal populations of bottlenose dolphins (Tursiops truncatus) after the major outbreaks that occurred in the 1980s and 1990s. Bottlenose dolphins from Beaufort, North Carolina; St. Joseph Bay, Florida; and Cape May, New Jersey had anti‐DMV seroprevalences ranging from between 15% and 33% but those from Charleston, South Carolina and Sarasota Bay, Florida, sampled in recent years were largely negative. These latter groups are therefore now vulnerable to infection and could experience high mortality if exposed to CeMV. Sero‐surveys of this kind are therefore vital for assessing the risk of new and recurring viral outbreaks in coastal cetaceans.     

Environmental influences on the productivity of three desert succulents in the south-western United States

Abstract Net CO₂ uptake over 24 h periods for shoots of Agave deserti, Ferocactus acanthodes, and Opuntia ficus-indica was measured under the ranges of water status, air temperature, and photo-synthetically active radiation (PAR) that occur in the south-western U.S.A. An environmental productivity index (EPI) was constructed indicating the overall influence of these three factors on net CO₂ uptake. Using growth chambers whose conditions were changed monthly to simulate the environmental conditions at a field site, the observed shoot dry weight increases per unit surface area changed in concert with monthly changes in EPI. The observed dry weight gain of the shoot was 17–19% lower than the predicted shoot net CO₂ uptake, which could be accounted for by carbon diversion to the roots. Mean monthly EPI was also predicted for 21 sites in the south-western U.S.A. All three species had low EPIs in the Colorado River basin, which has low annual rainfall and high summer temperatures, and in the north-central part of the region, which has low temperatures and low PAR during winter when water is available. The two native species, A. deserti and F. acanthodes, had high EPIs beyond their range in coastal southern California, where competition by other vegetation for PAR may limit net CO₂ uptake. Such regions as well as south-central California and south-central Arizona had high EPIs for all three species, indicating that these areas would be appropriate for the cultivation of O. ficus-indica.     

The racial disparity in breast cancer mortality in the 25 largest cities in the United States

Introduction: Although the racial disparity in breast cancer mortality is widely discussed there are no studies that analyze this phenomenon at the city level. Methods: We used national death files, abstracting those cases for which the cause was malignant neoplasm of the breast (ICD-10 = C50) for the numerators and American Community Survey data for the denominators. The 25 largest cities in the US were the units of analysis. Non-Hispanic Black:non-Hispanic White rate ratios (RRs) were calculated, along with their confidence intervals, as measures of the racial disparity. Seven ecological (city-level) variables were examined as possible correlates. Results: Almost all the NHB rates were greater than almost all the NHW rates. All but 3 of the RRs (range 0.78–2.09; median = 1.44) were >1, 13 of them significantly so. None of the RRs < 1 were significant. From among the 7 potential correlates, only median household income (r = ?0.43, p = 0.037) and a measure of segregation (r = 0.42, r = 0.039) were significantly related to the RR. Conclusion: This is the first study that we have been able to locate which examines city-level racial disparities in breast cancer mortality. The results are of concern for several cities and for the field in general. A strategy for reducing this disparity in Chicago is in place and may serve as a model for other cities wanting to initiate a similar process. Clearly it is time to take action.     

Phylogenetic affiliation of the bacteria that constitute phototrophic consortia

The phylogenetic affiliation of epibionts occurring in three morphologically distinct types of green-colored phototrophic consortia was investigated. Intact consortia of the types "Chlorochromatium aggregatum", "C. glebulum", and a third previously undescribed type, tentatively named "C. magnum" were mechanically separated from accompanying bacteria by either micromanipulation or by chemotactic accumulation in sulfide-containing capillaries. A 540-base-pair-long fragment of the 16S rRNA gene of the epibionts was amplified employing PCR primers specific for green sulfur bacteria. DNA fragments were separated by denaturing gradient gel electrophoresis and subsequently sequenced. The results of this phylogenetic analysis indicated that the symbiotic epibionts, together with only a few free-living strains, form a cluster within the green sulfur bacterial radiation which is only distantly related to the majority of known representatives of this phylum. Consortia with identical morphology but different origin exhibited significant differences in their partial 16S rRNA gene sequences, which could be confirmed by analysis of the 16S rRNA secondary structure. The phylogenetic affiliation of the chemotrophic central rod-shaped bacterium of "C. aggregatum" and "C. magnum" was analyzed by fluorescent in situ hybridization. According to our results and contrary to earlier assumptions, the central bacterium is a member of the beta-subgroup of the Proteobacteria.     

Breastfeeding in the United States

Abstract

The breastfeeding of U.S. infants born in 1974–76 is analyzed using data from the 1976 National Survey of Family Growth. It is found that the proportion of infants breastfed was increasing rapidly, with the highest rates found among white, college‐educated, western mothers and lowest rates among black mothers and mothers with less than a high‐school education. For children who were breastfed, the median duration was about 4.5 months and the mean 5.5 months, also with marked differences by ethnicity, education, and region. Data from other sources confirm these differences and quantify subsequent increases in breastfeeding.     

Ecosystem consequences of plant life form changes at three sites in the semiarid United States

Many semiarid rangelands have recently experienced changes in dominant plant life form. Both woody plant expansion into grasslands and the invasion of annual grasses into shrublands have potential influence on regional carbon cycling. Soil carbon content, chemistry, and distribution may change following shifts in dominant plant life form because plant life forms differ in litter chemistry and patterns of detrital input. This study assesses the amount, quality, and distribution of soil C below woody vegetation and grasses at three rangelands in Texas, New Mexico, and Utah. At each of these sites there has been a well-documented shift in dominant plant life form. In Texas and New Mexico, woody plants have increased in grasslands, while grasses have invaded into former shrublands in Utah. We measured total soil carbon, particulate organic matter (POM) C, and the carbon isotopic composition of soil carbon beneath woody plants and grasses at each of these three sites. At the La Copita Research Area in south-central Texas there was significantly more soil C found beneath Prosopis glandulosa, the dominant woody plant, than was found beneath grasses. Mean soil C content to 1 m was 7.2 kg C m^–2 beneath P. glandulosa and 6.0 kg C m^–2 beneath grasses. There was also significantly more POM C beneath P. glandulosa than beneath grasses. Stable carbon isotopic composition indicated that the expansion of P. glandulosa in savannas in Texas first influences carbon cycling in surface soils, then deep soil C, and finally throughout the soil profile. At the Sevilleta National Wildlife Refuge in central New Mexico, we found that there was significantly more soil C in the upper 10 cm of the soil profile beneath Larrea tridentata than was found beneath Bouteloua spp. Stable carbon isotopic composition indicated that the expansion of L. tridentata influenced C cycling throughout the soil profile. At Curlew Valley in northern Utah, we found no significant differences in total profile soil C beneath different plant life forms. However, there was significantly more soil C found at the soil surface beneath woody plants than was observed beneath annual grasses. There was significantly less POM C beneath annual grasses than was found beneath woody plants or perennial grasses. Based on stable carbon isotopic analyses, we concluded that the invasion of grasses into shrublands influenced only the upper 30 cm of the soil profile. We determined that following changes in plant life form dominance, the most consistent change in soil C was an alteration in content and distribution of POM C, a slowly cycling pool of soil C. While we failed to find a consistent change in total profile soil C with plant life form across our sites, the change in soil C chemistry may have important implications for long-term soil C storage in semiarid systems where there have been shifts in plant life form. Received: 30 March 1999 / Accepted: 11 August 1999     

A comparison of three geographical isolates of Trichinella spiralis from the mid-Atlantic United States

Three isolates of Trichinella spiralis (black bear: 41o50'N, 79o00'W, 1982; grey fox: 41o00'N, 76o00'W, 1982; domestic pig: 39o80'N, 75o30'W, 1983) from the mid-Atlantic United States were characterized in Crl: COBS CFW (SW) mice during 10 successive 40-day generations. Over 10 generations, the isolates differed as follows: worm position of the ursine isolate was significantly more posteriad compared to the porcine isolate; sex ratio of the vulpine isolate was significantly lower compared to the ursine and porcine isolates; females of the porcine isolate produced significantly more newborn larvae in vitro than the sylvatic isolates; both the larvae per gram (LPG) and reproductive capacity index (RCI) were significantly higher for the porcine isolate; and male worms of the vulpine isolate were significantly smaller than those of the porcine or ursine isolates. No differences were observed among isolates for percentage of inoculum recovered, length of female worms, or uterine length. The fecundity of the isolates in hamsters, gerbils, multimammate rats, Sprague-Dawley rats, and Peromyscus sp. was examined also. Based upon RCI and LPG, the porcine isolate was the most fecund in all hosts except gerbils. This higher fecundity was often manifest as increased morbidity and mortality in hosts infected with this isolate. The relationship between the virulent nature of the porcine isolate and the enhanced transmission of T. spiralis are discussed.     

Emergence and rapid transmission of SARS-CoV-2 B.1.1.7 in the United States

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