The Arctic Plant Aboveground Biomass Synthesis Dataset

Plant biomass is a fundamental ecosystem attribute that is sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant biomass in the Arctic is logistically challenging and resource intensive. Lack of accessible field data hinders efforts to understand the amount, composition, distribution, and changes in plant biomass in these northern ecosystems. Here, we present The Arctic plant aboveground biomass synthesis dataset, which includes field measurements of lichen, bryophyte, herb, shrub, and/or tree aboveground biomass (g m-2) on 2,327 sample plots from 636 field sites in seven countries. We created the synthesis dataset by assembling and harmonizing 32 individual datasets. Aboveground biomass was primarily quantified by harvesting sample plots during mid- to late-summer, though tree and often tall shrub biomass were quantified using surveys and allometric models. Each biomass measurement is associated with metadata including sample date, location, method, data source, and other information. This unique dataset can be leveraged to monitor, map, and model plant biomass across the rapidly warming Arctic.

A Second Look at Niacin

Niacin is the third vitamin to be discovered and, therefore. is known as vitamin B3. It has a long history of medicinal use-nutritionally and as a skin tone brightening agent in skin care. Recent studies have suggested that niacin could be useful as an adjunctive treatment for coronavirus disease 2019 (COVID-19) and mitigating the damaging effect of blue light to the skin. Niacin, also known as nicotinic acid, nicotinamide, and niacinamide, is a physiologically active form of vitamin B3. Medicinal benefits of niacin were observed in 1902, when for the first time, patients with pellagra were treated with yeast that contained vitamin B3. Niacin has a variety of uses, particularly in treating various skin conditions, including topically as an anti-acne treatment, promoting epidermal sphingolipid synthesis, moderating photoimmunosuppression, and reducing hyperpigmentation. Niacinamide could be beneficial as an adjunctive treatment for COVID-19 and for decreasing stress if the skin is excessively exposed to blue light.

Soil and plant-based ecosystem functions dataset of three land-use types in northwestern Virginia

Variables that quantify nutrient cycling in terrestrial ecosystems, including aboveground and belowground biomass, litter biomass, inorganic nitrogen (NH₄ ⁺ and NO₃ ^-), and soil CO₂ efflux were measured in situ. From measured variables, seasonal litter inputs and nitrogen mineralization were also estimated. Data were collected over the course of one to two growing seasons (2017 and 2018) across three different land-use types under variable human management: an agricultural field (cultivating millet for the duration of the first growing season of the study and left fallow for the duration of the second growing season), a restored native C₄ tallgrass prairie, and an approximately 16-year-old successional field. The area of focus within each field was approximately 1 hectare. Five representative 5 m x 5 m plots were randomly chosen in each of the three fields. Within each 5 m x 5 m plot, three 1 m² subplots were randomly chosen for replicate sampling. These raw data can be utilized to calculate the ecosystem functions of net nitrogen (N) mineralization, decomposition, soil respiration, aboveground primary productivity, and N leaching, which are foundational components of supporting ecosystem services in terrestrial soils and plants. These data can be used in conjunction with other datasets that describe a suite of ecosystem functions in different land-use types under variable management.

Attack on Sunscreens Continues

The Food and Drug Administration (FDA) was required to issue and put into effect a final sunscreen monograph by November 26, 2019. On March 27, 2020, President Donald Trump signed into effect H.R. 748, the "Coronavirus Aid, Relief, and Economic Security Act" (CARES). This bill eliminated the November 2019 requirement. The CARES Act includes legislative reforms that modernize the way over-the-counter (OTC) monograph drugs are regulated in the United States. Under this Act, sunscreens will be considered generally recognized as safe and effective (GRASE), if they meet conditions newly defined by the FDA. In addition, the FDA is required to issue a proposal to revise the sun-screen requirements for GRASE not later than 18 months after enactment and will sunset by the end of the fiscal year 2022. The CARES Act also addresses the requirement for a new drug application (NDA).^1-7.

The Impact of Visible Light on Skin

Visible (VIS) light (400-700 nm), including blue light (400-500 nm), represents approximately 50% of the full optical solar spectrum. It is known since 1938 that visible light penetrates the skin. Biologic markers to fully interpret the significance of such penetration were not utilized at that time to determine the potential damage caused to the skin. The mechanisms of VIS light-induced pigmentation and melanogenesis are currently being investigated by the skin care industry.

Influence of Sex Ratio and Density on the Comparative Repellency of IR3535® Against Caged Aedes, Anopheles, and Culex Mosquitoes

Studies on topical repellent efficacy conducted with caged mosquitoes in the laboratory are important to both the development and regulation of insect repellents. Guidelines for laboratory studies stipulate specific densities, sex ratios, and biting rates, whereas those for field studies are governmentally required before a promising repellent can be registered for human use. These protocols stipulate minimum biting rates alone. Relatively little is known, however, about the influence of mosquito density and sex ratio on their biting propensity, either in the field or laboratory. Using Environmental Protection Agency guidelines for cage testing, we studied the influence of mosquito density and sex ratio in laboratory repellency tests of the biopesticide Ethyl butylacetylaminopropionate (IR3535^™) (20%) against three mosquito species (Aedes aegypti, Anopheles aquasalis, and Culex quinquefasciatus). DEET [3-(N-acetyl-N-butyl) aminopropionic acid ethyl ester] (20%) in a laboratory prepared formulation was used as a comparison article. Studies were conducted by trained investigators at the BioAgri Laboratories in Brazil. We found that higher mosquito density generally decreased protection time, but that the influence of sex ratio was more complex. The presence of male mosquitoes increased protection times against Aedes and Anopheles perhaps because mate-seeking males interfered with female feeding. Interestingly, by contrast, protection times decreased against Culex in the presence of males. Such considerations may potentially assist in improving the match between cage and field testing under a broader range of conditions that permit more accurate labeling of repellents for safe and effective use by consumers.

Use of a Digital Medication Management System for Effective Assessment and Enhancement of Patient Adherence to Therapy (ReX): Feasibility Study

Background

Medication nonadherence is a major problem in health care, imposing poor clinical outcomes and a heavy financial burden on all stakeholders. Current methods of medication adherence assessment are severely limited: they are applied only periodically, do not relate to actual pill intake, and suffer from patient bias due to errors, misunderstanding, or intentional nonadherence. ReX is an innovative medication management system designed to address poor patient adherence and enhance patient engagement with their therapy. ReX controls and tracks pills from the point of packaging right through to the patient’s mouth. ReX generates robust, real-time adherence data. The system enables patients to report outcomes, complete surveys, and receive messages and instructions. ReX includes a reusable drug dispensing unit, disposable cassette containing pills, and a cloud-based data portal.

Objective

We aimed to evaluate ReX feasibility by human factor studies including evaluation of ReX safety; ReX acceptance and usability; and ReX efficacy of providing pills according to a preprogrammed dose regimen, managing reminders and adherence data, and enhancing the adherence rate compared with the standard of care.

Methods

The ReX system was evaluated in 2 human factor, nonclinical feasibility studies. Human subjects used ReX for the administration of pill-shaped Tic Tac sweets. The initial study evaluated ReX use and pill intake administration; second was a self-controlled, 4-day home-use study. All subjects took pills at home, according to a preprogrammed dose regimen, for 4 days each via the device (ReX test) or from standard packaging (control test). The adherence rate (percent of pills taken) was measured by the study subject’s report, remaining pills count, and ReX records (in the ReX test). ReX safety and usability were evaluated by a questionnaire filled out by the subject.

Results

The initial feasibility study evaluated usability and acceptance of the ReX novel approach to pill dispensing. All subjects successfully managed 2 pill intakes. The ReX device was rated as easy to use by 81% (48/59) of subjects. The 4-day home-use study evaluated the safety, efficacy, and usability of the ReX system. No adverse event occurred; no pill overdose or pill malformation was reported. The overall adherence rate in the ReX test was 97.6% compared with 76.3% in the control test (P<.001). Real-time, personalized reminders provided in the event of a delay in pill intake contributed to 18.0% of doses taken during the ReX test. The ReX system was found easy to use by 87% (35/40) of subjects; 90% (36/40) felt comfortable using it for their medication.

Conclusions

ReX’s novel “tracking to the mouth” technology was found usable and accepted by subjects. The assessment of adherence rates was reliable; adherence of subjects to the dose regimen was significantly enhanced when using ReX compared with the standard of care.

Circumpolar arctic tundra biomass and productivity dynamics in response to projected climate change and herbivory

Satellite remote sensing data have indicated a general 'greening' trend in the arctic tundra biome. However, the observed changes based on remote sensing are the result of multiple environmental drivers, and the effects of individual controls such as warming, herbivory, and other disturbances on changes in vegetation biomass, community structure, and ecosystem function remain unclear. We apply ArcVeg, an arctic tundra vegetation dynamics model, to estimate potential changes in vegetation biomass and net primary production (NPP) at the plant community and functional type levels. ArcVeg is driven by soil nitrogen output from the Terrestrial Ecosystem Model, existing densities of Rangifer populations, and projected summer temperature changes by the NCAR CCSM4.0 general circulation model across the Arctic. We quantified the changes in aboveground biomass and NPP resulting from (i) observed herbivory only; (ii) projected climate change only; and (iii) coupled effects of projected climate change and herbivory. We evaluated model outputs of the absolute and relative differences in biomass and NPP by country, bioclimate subzone, and floristic province. Estimated potential biomass increases resulting from temperature increase only are approximately 5% greater than the biomass modeled due to coupled warming and herbivory. Such potential increases are greater in areas currently occupied by large or dense Rangifer herds such as the Nenets-occupied regions in Russia (27% greater vegetation increase without herbivores). In addition, herbivory modulates shifts in plant community structure caused by warming. Plant functional types such as shrubs and mosses were affected to a greater degree than other functional types by either warming or herbivory or coupled effects of the two.

Correlating species and spectral diversities using hyperspectral remote sensing in early-successional fields

Advances in remote sensing technology can help estimate biodiversity at large spatial extents. To assess whether we could use hyperspectral visible near‐infrared (VNIR) spectra to estimate species diversity, we examined the correlations between species diversity and spectral diversity in early‐successional abandoned agricultural fields in the Ridge and Valley ecoregion of north‐central Virginia at the Blandy Experimental Farm. We established plant community plots and collected vegetation surveys and ground‐level hyperspectral data from 350 to 1,025 nm wavelengths. We related spectral diversity (standard deviations across spectra) with species diversity (Shannon–Weiner index) and evaluated whether these correlations differed among spectral regions throughout the visible and near‐infrared wavelength regions, and across different spectral transformation techniques. We found positive correlations in the visible regions using band depth data, positive correlations in the near‐infrared region using first derivatives of spectra, and weak to no correlations in the red‐edge region using either of the two spectral transformation techniques. To investigate the role of pigment variability in these correlations, we estimated chlorophyll, carotenoid, and anthocyanin concentrations of five dominant species in the plots using spectral vegetation indices. Although interspecific variability in pigment levels exceeded intraspecific variability, chlorophyll was more varied within species than carotenoids and anthocyanins, contributing to the lack of correlation between species diversity and spectral diversity in the red‐edge region. Interspecific differences in pigment levels, however, made it possible to differentiate these species remotely, contributing to the species‐spectral diversity correlations. VNIR spectra can be used to estimate species diversity, but the relationships depend on the spectral region examined and the spectral transformation technique used.

Effects of legume species introduction on vegetation and soil nutrient development on abandoned croplands in a semi-arid environment on the Loess Plateau, China

Revegetation facilitated by legume species introduction has been used for soil erosion control on the Loess Plateau, China. However, it is still unclear how vegetation and soil resources develop during this restoration process, especially over the longer term. In this study, we investigated the changes of plant aboveground biomass, vegetation cover, species richness and density of all individuals, and soil total nitrogen, mineral nitrogen, total phosphorus and available phosphorus over 11 years from 2003 to 2013 in three treatments (natural revegetation, Medicago sativa L. introduction and Melilotus suaveolens L. introduction) on the semi-arid Loess Plateau. Medicago significantly increased aboveground biomass and vegetation cover, and soil total nitrogen and mineral nitrogen contents. The Medicago treatment had lower species richness and density of all individuals, lower soil moisture in the deep soil (i.e., 1.4-5m), and lower soil available phosphorus. Melilotus introduction significantly increased aboveground biomass in only the first two years, and it was not an effective approach to improve vegetation biomass and cover, and soil nutrients, especially in later stages of revegetation. Overall, our study suggests that M. sativa can be the preferred plant species for revegetation of degraded ecosystems on the Loess Plateau, although phosphorus fertilizer should be applied for the sustainability of the revegetation.

A protocol for addressing acute pain and prescribing opioids

Physicians across the country are re-examining their role in the prescription opioid abuse problem. In response to growing public awareness about the dangers of opioids, the Minnesota Medical Association formed a Prescription Opioid Management Advisory Task Force. As part of its work, the task force partnered with the Institute for Clinical Systems Improvement (ICSI) to develop a protocol for prescribing opioids for acute pain. This article describes the development of the new ICSI Acute Pain Assessment and Appropriate Opioid Prescribing Protocol and highlights key aspects of the protocol, which emphasizes shared decision-making and careful, conservative prescribing.

Route of administration-dependent anti-inflammatory effect of liposomal alendronate

Innate immunity and inflammation are of major importance in various pathological conditions. Intravenous (IV) and intraperitoneal (IP) liposomal alendronate (LA) treatments have been shown to deplete circulating monocytes and peritoneal macrophages resulting in the inhibition of restenosis and endometriosis (EM), respectively. Nevertheless, the correlation between the extent of circulating monocyte depletion and liposome biodistribution is unknown, and the route of administration-dependent bioactivity in restenosis and EM has not been determined. We found that, LA treatment resulted in a dose-response modified biodistribution following both IV and IP administrations. The biodistribution of high-dose LA (10mg/kg), but not that of the low-dose (1mg/kg), was similar in healthy and diseased animals. It is concluded that LA impedes its own elimination from the circulation by depleting circulating monocytes and/or inhibiting their endocytic activity, in a dose-dependent manner. Both IV and IP administration of LA mediated by the partial and transient depletion of circulating monocytes effected inhibition of restenosis. Inhibition of EM was effected only by IP administration, which depleted both intraperitoneal and circulating monocytes. Thus, EM should be considered as a local inflammatory condition with systemic manifestations as opposed to restenosis, a systemic inflammatory disease.

Cosmeceutical vehicles

Consumers will pay a premium for high-performance skin and hair care products. The demand exists, and in return for the high cost, consumers expect the product to perform as claimed and to meet aesthetic standards beyond many products found in the mass market. To be successful in this highly competitive market, products must function as claimed or consumers will not repurchase. Effective contemporary high-end products must be properly formulated in nonirritating vehicles that consumers will perceive as elegant.

Cosmeceuticals and polyphenols

Phenolic compounds found in plants are believed to be effective in prevention of oxidative stress related diseases. An interest in antioxidants and natural foods continues to grow along with a commercial interest in plant-derived phenolic products. Flavonoids represent a family of plant compounds high in phenolic related antioxidant activity. They are poorly absorbed in the body. Many published studies show the antioxidant activity of the flavonoid, but fail to consider the activity of the metabolite which is actually bioavailable to the body. The paper concludes that there remains a need to develop adequate physiological models supporting antioxidant activity of polyphenols.

Innate immunity has a dual effect on vascular healing: suppression and aggravation of neointimal formation and remodeling post-endotoxin challenge

BACKGROUND

Inflammation is important to vascular repair following injury, modulating neointimal proliferation and remodeling. Previously, we have shown that a low-intensity inflammatory response aggravates neointimal formation following balloon and stent injury. The present study examined whether modulation of the extent and timing of nonspecific inflammation mediates the local vascular response in an additive unidirectional or rather a bidirectional fashion.

METHODS AND RESULTS

Rabbits subjected to denudation and balloon injury of the iliac artery were treated with low (1 microg/kg) or high (100 microg/kg) doses of bacterial endotoxin (LPS) immediately after injury, or with early high-dose LPS administered 3 days prior to injury (preconditioning). Neointimal formation at 28 days was significantly increased in the low-dose group (0.537+/-0.059 mm(2)) as compared with controls (0.3+/-0.03 mm(2)). High-dose LPS did not significantly affect neointimal formation while early high dose significantly reduced neointima (0.296+/-0.033 and 0.194+/-0.025 mm(2), respectively, n=12-14/group). Arterial wall and systemically circulating interleukin-1 beta levels, and monocyte CD14 activation correlated with neointimal formation. Vascular remodeling was accelerated in animals treated with low- or high-dose LPS while not affected in the preconditioned group. Remodeling index inversely correlated with arterial matrix metalloproteinase-2 levels 6 days after injury.

CONCLUSIONS

The extent and timing of nonspecific inflammation that is concurrent with vascular injury can determine different and opposite vascular repair patterns.

Effective inhibition of melanosome transfer to keratinocytes by lectins and niacinamide is reversible

Skin pigmentation results in part from the transfer of melanized melanosomes synthesized by melanocytes to neighboring keratinocytes. Plasma membrane lectins and their glycoconjugates expressed by these epidermal cells are critical molecules involved in this transfer process. In addition, the derivative of vitamin B(3), niacinamide, can inhibit melanosome transfer and induce skin lightening. We investigated the effects of these molecules on the viability of melanocytes and keratinocytes and on the reversibility of melanosome-transfer inhibition induced by these agents using an in vitro melanocyte-keratinocyte coculture model system. While lectins and neoglycoproteins could induce apoptosis in a dose-dependent manner to melanocytes or keratinocytes in monoculture, similar dosages of the lectins, as opposed to neoglycoproteins, did not induce apoptosis to either cell type when treated in coculture. The dosages of lectins and niacinamide not affecting cell viability produced an inhibitory effect on melanosome transfer, when used either alone or together in cocultures of melanocytes-keratinocytes. Cocultures treated with lectins or niacinamide resumed normal melanosome transfer in 3 days after removal of the inhibitor, while cocultures treated with a combination of lectins and niacinamide demonstrated a lag in this recovery. Subsequently, we assessed the effect of niacinamide on facial hyperpigmented spots using a vehicle-controlled, split-faced design human clinical trial. Topical application of niacinamide resulted in a dose-dependent and reversible reduction in hyperpigmented lesions. These results suggest that lectins and niacinamide at concentrations that do not affect cell viability are reversible inhibitors of melanosome transfer.

Health needs of the Roma population in the Czech and Slovak Republics

In the growing literature on the human rights of Roma people in Central Europe, their relatively poor health status is often mentioned. However, little concrete information exists about the contemporary health status of the Roma in this region. We sought information on the health of the Roma in two of countries with significant Roma minorities, the Czech and Slovak Republics, by means of systematic searches for literature on the health of Roma people published in Czech or Slovak or by authors from the two countries. Published research on health of the Roma population is sparse. The topics that have received attention suggest a focus on concepts of contagion or social Darwinism, indicating a greater concern with the health needs of the majority populations with which they live. What limited evidence exists indicates that the health needs of the Roma population are considerable. With very few exceptions, the health status of Roma is worse than that of non-Roma population in both countries. The burden of communicable disease among Roma is high and diseases associated with poor hygiene seem to be particularly important. Evidence on health care suggests poor communication between Roma and health workers and low uptake of preventative care. The health needs of Roma lack visibility, not only because of the absence of research but also the absence of advocacy on their behalf. Since 1989, Czech and Slovak researchers have largely turned away from health research on particular ethnic groups. This probably reflects a growing sensitivity about stigmatising Roma, but it also makes it difficult to know how their circumstances might be improved. There is a need for further research into the health of Roma people with particular emphasis on non-communicable disease and for interventions that would improve their health.

Lack of association between anti-V3 loop antibodies and perinatal transmission of HIV-1 in Kampala, Uganda

This study evaluated the association between reactivity of maternal antibody to human immunodeficiency virus type 1 (HIV-1) V3 loop peptides and perinatal transmission in Uganda. Plasma from 40 HIV-1-infected mothers (20 transmitting and 20 nontransmitting mothers) and 31 uninfected mothers in Uganda were tested for reactivity and antibody titer to synthetic peptides representing V3 loop sequences from HIV-1 strains MN, SF2, LAI, ZR6, and CM235 and consensus peptides CA, CB, and CD. No significant differences were found between 20 transmitting mothers and 20 nontransmitting mothers in terms of percent reactivity or titer of antibody to any of the V3 loop peptides tested. Use of a multivariable logistic model to adjust for beta-2 microglobulin level as a confounding variable of stage of infection did not help demonstrate an association except possibly for the ZR6 peptide. These data suggest that neither reactivity nor maternal antibody titer to V3 loop peptides are protective against perinatal transmission of HIV-1 in Uganda.

Terazosin in the treatment of benign prostatic hyperplasia. Terazosin Benign Prostatic Hyperplasia Study Group

OBJECTIVE

To evaluate the efficacy and tolerability of terazosin, a long-acting selective alpha 1-receptor antagonist, in patients with benign prostatic hyperplasia.

DESIGN AND SETTING

Randomized, double-blind, multicenter (eight government and private facilities), placebo-controlled study.

PATIENTS

Men aged 45 years or older, with qualifying signs and symptoms of benign prostatic hyperplasia (n = 160).

INTERVENTIONS

Terazosin or placebo once daily, with terazosin dosage titrated to the patient's response. After a 4-week placebo lead-in, 1 to 10 mg of terazosin or placebo was administered for 24 weeks.

OUTCOME MEASURES

Decreases in mean Boyarsky scores for obstructive and irritative symptoms and total scores and increases in peak urine flow rate.

RESULTS

Terazosin-treated patients had decreases in Boyarsky obstructive, irritative, and total scores of 3.3 (52%), 1.3 (29%), and 4.6 (42%), respectively, compared with decreases of 0.7 (12%), 0.4 (9%), and 1.1 (11%), respectively, in the placebo group (P < .05). Peak urine flow increased by a mean of 2.6 mL/s (30%) in terazosin-treated patients and 1.2 mL/s (14%) in placebo-treated patients (P < or = .05). Adverse events that differed significantly in the two groups were dizziness (19% in the terazosin group vs 5% in the placebo group) and urinary tract infection (1% in the terazosin group vs 10% in the placebo group).

CONCLUSIONS

These results suggest that terazosin given once daily in doses up to 10 mg alleviates symptoms and improves peak urine flow rate in men with benign prostatic hyperplasia and has an acceptable adverse event profile.

Effect of total parenteral nutrition on amino acid and glucose transport by the human small intestine

OBJECTIVE

The effect of total parenteral nutrition (TPN) on small intestinal amino acid transport activity was studied in humans.

SUMMARY BACKGROUND DATA

Studies in humans receiving TPN indicate that a decrease in the activities of the dissacharidase enzymes occurs, but morphologic changes are minimal with only a slight decrease in villous height.

METHODS

Surgical patients were randomized to receive TPN (n = 6) or a regular oral diet (controls, n = 7) for 1 week before abdominal surgery. Ileum (5 controls, 5 TPN) or jejunum (2 controls, 1 TPN) were obtained intraoperatively and brush-border membrane vesicles (BBMV) were prepared by magnesium aggregation/differential centrifugation. Transport of L-MeAlB (a selective system A substrate), L-glutamine, L-alanine, L-arginine, L-leucine, and D-glucose was assayed by a rapid mixing/filtration technique in the presence and absence of sodium.

RESULTS

Vesicles demonstrated approximately 18-fold enrichments of enzyme markers, classic overshoots, transport into an osmotically active space, and similar 1-hour equilibrium values. TPN resulted in a 26-44% decrease in the carrier-mediated transport velocity of all substrates except glutamine across ileal BBMVs. In the one patient receiving TPN from whom jejunum was obtained, there was also a generalized decrease in nutrient transport, although glutamine was least affected. Kinetic studies of the system A transporter demonstrated that the decrease in uptake was secondary to a reduction in carrier Vmax, consistent with a decrease in the number of functional carriers in the brush-border membrane.

CONCLUSIONS

TPN results in a decrease in brush-border amino acid and glucose transport activity. The observation that glutamine transport is not downregulated by 1 week of bowel rest may further emphasize the important metabolic role that glutamine plays as a gut fuel and in the body's response to catabolic stresses.

Kinesins in the spindle: an update

Eukaryotes contain a superfamily of microtubule-based motor proteins comprising kinesin and a number of related proteins that are thought to participate in various forms of intracellular motility, including cell division and organelle transport. The role of various members of the kinesin superfamily in chromosome segregation and spindle morphogenesis was described in TCB last year in parts of a series on cytoplasmic motor proteins. In this brief update, Helen Epstein and Jon Scholey comment on new findings that have improved our understanding of the functions of kinesin-related proteins in mitosis and meiosis.

Cloning and expression of Drosophila HP1 homologs from a mealybug, Planococcus citri

The mealybug chromosome cycle is one of the most dramatic examples of genomic imprinting known. In embryos that are to become male the entire paternal chromosome set becomes heterochromatic and inactive at the blastoderm stage, while the maternal set remains active and euchromatic. HP1 is a protein from Drosophila melanogaster, which binds preferentially to heterochromatin on polytene chromosomes and is likely to be a modifier of position effect variegation. This paper describes the isolation and sequencing of two cDNA clones encoding HP1 homologs from the mealybug, Planococcus citri. The protein product of the cDNA clone that was closer to HP1 in sequence was expressed as a fusion protein in Escherichia coli, and polyclonal rat antibodies were raised against it. Immunohistochemistry to mealybug squash preparations showed that this protein was a male-specific nuclear protein, but that it was not specifically associated with the heterochromatic set of chromosomes.

Acute reversible hypoxemia in systemic lupus erythematosus

OBJECTIVE

To determine the frequency of unexplained reversible hypoxemia in patients with systemic lupus erythematosus and to assess the relation between hypoxemia and elevated plasma levels of complement split products.

DESIGN

Cohort study.

SETTING

Inpatient and outpatient facilities of the New York University Medical Center/Bellevue Hospital and the Hospital for Joint Diseases.

PATIENTS

Case patients were 22 patients hospitalized with disease exacerbation and no evidence of parenchymal lung disease on chest roentgenogram. Four patients with stable disease were followed in the outpatient clinic, and five healthy normal volunteers served as controls.

MEASUREMENTS

Plasma levels of complement split products (C3a, factor Bb fragment), alveolar-arterial (A-a) Po2 gradients, and pulmonary function were measured.

MAIN RESULTS

Nine episodes of hypoxemia or hypocapnia (mean A-a gradient, 30.4 +/- 4.8 mm Hg) or both (despite normal chest roentgenogram results) were noted in six hospitalized patients (group 1). Gas exchange improved within 72 hours of steroid therapy (mean A-a gradient, 11.6 +/- 4.3 mm Hg; P less than 0.01). These patients had an elevated initial mean C3a level (938.4 +/- 246.8 ng/mL) that decreased within 72 hours (407.8 +/- 80.9 ng/mL; P less than 0.01), concomitant with improved oxygenation. Ventilation-perfusion scans, obtained for four of six group 1 patients, excluded pulmonary emboli. Four hospitalized patients (group 2) had a normal A-a gradient (mean, 7.5 +/- 2.7 mm Hg). The mean C3a level of this group (358.3 +/- 39.2 ng/mL) was lower than that of group 1 (P less than 0.05). Four patients with stable disease (group 3) had a mean A-a gradient and a mean C3a level of 3.3 +/- 2.7 mm Hg and 237.8 +/- 105.7 ng/mL, respectively, similar to values found in five normal volunteers, in whom the mean A-a gradient was 3.7 +/- 1.7 mm Hg and the mean C3a level was 124.8 +/- 9.2 ng/mL.

CONCLUSION

A syndrome of reversible hypoxemia, unassociated with parenchymal lung disease, is unexpectedly common in acutely ill, hospitalized patients with systemic lupus erythematosus. The pathogenesis of this syndrome is unclear, although the data are compatible with the hypothesis that hypoxemia may be related to pulmonary leukoaggregation.

The human class I MHC gene HLA-F is expressed in lymphocytes

Genomic and cDNA clones encoding a human, non-classical class I gene, Dew3, have been isolated. The complete coding sequence has been determined. The sequence is capable of directing expression of a protein with high sequence homology to HLA-A,B,C molecules but with a shortened cytoplasmic tail. Sequence comparisons demonstrate that this gene is from a separate locus to the 'classical' HLA-A,B,C and 'non-classical' HLA-E and HLA-G loci. Dew3 is equally distantly related to all of these previously described, functional class I genes. It is, however, extremely homologous to a third 'non-classical' gene, HLA-5.4, and to the chimpanzee gene, Ch28. The RNA species it transcribes is shorter than that of the classical genes, due to an altered acceptor splice site which results in the loss of exon 7. The transcription of Dew3 RNA shows a unique pattern of tissue distribution, being expressed in B cell lines and peripheral blood lymphocytes and absent from T cell lines, fibroblasts and a myelomonocytic leukaemia. A Dew3 protein product was detected after transfection into a human EBV-transformed B cell line but was located intracellularly. The HLA-5.4 gene has been recently designated HLA-F. The Dew3 and X5.1 clones thus represent two new alleles of the HLA-F locus in man. Sequence comparison with its chimpanzee homologue suggests that selective pressure for conservation of amino acid sequence is still maintained at this locus.

Volume adjustment of mechanics and diffusion in interstitial lung disease. Lack of clinical relevance

Relationships of lung mechanics and diffusion to lung volume were examined in 38 patients with interstitial lung disease to determine whether patterns of reduction relate to severity of disease, distinguish histologic characteristics or predict prognosis for reversibility. Normal volume-related values for both mechanics and diffusion were seen throughout the range of severity of disease. The ratio of mechanics to lung volume did not correlate with the ratio of diffusion to lung volume in the same patient. Volume relationships of mechanics and diffusion failed to distinguish pathologic predominance of fibrosis or inflammation/granulomas. These ratios failed to predict reversibility in patients who had repeated tests. These results suggest that in patients with interstitial lung disease the significance of "volume-adjustment" of mechanics and diffusion should be viewed with caution; these parameters do not appear to contribute to the assessment of pathophysiology or correlate with clinical spectrum of interstitial lung diseases.

Expression and function of HLA-A2.1 in transgenic mice

We have derived a number of transgenic mouse lines which express the human major histocompatibility complex class I gene HLA-A2.1. Two lines carry the complete human HLA-A2.1, the others bear a recombinant gene in which the HLA-A2.1 coding regions are fused to the H-2Kb promoter. Analysis of transgenic spleen cells by immunofluorescence demonstrates that these mouse cells express HLA-A2.1 on their surface in association with mouse beta 2-microglobulin (beta 2m), confirming that HLA-A2 does not require human beta 2m to be expressed at the cell surface. The cells contain more HLA mRNA than endogenous H-2 class I mRNA. There is also a large pool of non-beta 2m-associated HLA heavy chain inside the cell. In contrast the amount of HLA:beta 2m complex is low. Thus, in transgenic mice HLA-A2 seems to compete poorly with H-2 heavy chains for mouse beta 2m. The HLA-A2.1 transgenic mice do not produce influenza-virus-specific cytotoxic T cells (CTL) restricted to the HLA transgene, at least in sufficient numbers to be measured in a direct bulk CTL assay. The dominance of H-2-restricted clones may be the result of quantitative rather than qualitative factors. However, HLA-A2.1 transgenic spleen cells are effective in stimulating an allogeneic CTL response in normal mice. This response is not H-2 restricted. Cold target inhibition studies show that there are at least two populations of CTL, one of which is specific for HLA-A2.1 on mouse cells. This result suggests that at least some allo-CTL are directed against major histocompatibility complex plus "self-peptide".

An insertion mutation in the pol gene of Moloney murine leukemia virus results in temperature-sensitive pol maturation and viral replication

An insertion mutation in the pol gene of Moloney murine leukemia virus (M-MuLV) was found to render the virus temperature-sensitive for replication. A provirus containing a 12-bp insertion at the boundary between the reverse transcriptase (RT) and integrase (IN) domains induced the formation of mutant virions containing a partially processed RT-IN fusion protein. Some proteolytic processing to form mature RT and IN was observed at 32 degrees, but only aberrantly processed proteins were detected at 39 degrees. The uncleaved precursor was found to exhibit DNA polymerase activity, even though it could not support replication of the virus in vivo at 39 degrees.