A High-Throughput, High-Containment Human Primary Epithelial Airway Organ-on-Chip Platform for SARS-CoV-2 Therapeutic Screening

COVID-19 emerged as a worldwide pandemic in early 2020, and while the rapid development of safe and efficacious vaccines stands as an extraordinary achievement, the identification of effective therapeutics has been less successful. This process has been limited in part by a lack of human-relevant preclinical models compatible with therapeutic screening on the native virus, which requires a high-containment environment. Here, we report SARS-CoV-2 infection and robust viral replication in PREDICT96-ALI, a high-throughput, human primary cell-based organ-on-chip platform. We evaluate unique infection kinetic profiles across lung tissue from three human donors by immunofluorescence, RT-qPCR, and plaque assays over a 6-day infection period. Enabled by the 96 devices/plate throughput of PREDICT96-ALI, we also investigate the efficacy of Remdesivir and MPro61 in a proof-of-concept antiviral study. Both compounds exhibit an antiviral effect against SARS-CoV-2 in the platform. This demonstration of SARS-CoV-2 infection and antiviral dosing in a high-throughput organ-on-chip platform presents a critical capability for disease modeling and therapeutic screening applications in a human physiology-relevant in vitro system.

Tetravalent Rabies-Vectored Filovirus and Lassa Fever Vaccine Induces Long-term Immunity in Nonhuman Primates

BACKGROUND

The objective of this study is to evaluate the immunogenicity of adjuvanted monovalent rabies virus (RABV)-based vaccine candidates against Ebola virus (FILORAB1), Sudan virus (FILORAB2), Marburg virus (FILORAB3), Lassa virus (LASSARAB1), and combined trivalent vaccine candidate (FILORAB1-3) and tetravalent vaccine candidate (FILORAB1-3 and LASSARAB) in nonhuman primates.

METHODS

Twenty-four Macaca fascicularis were randomly assigned into 6 groups of 4 animals. Each group was vaccinated with either a single adjuvanted vaccine, the trivalent vaccine, or the tetravalent vaccine at days 0 and 28. We followed the humoral immune responses for 1 year by antigen-specific enzyme-linked immunosorbent assays and RABV neutralization assays.

RESULTS

High titers of filovirus and/or Lassa virus glycoprotein-specific immunoglobulin G were induced in the vaccinated animals. There were no significant differences between immune responses in animals vaccinated with single vaccines vs trivalent or tetravalent vaccines. In addition, all vaccine groups elicited strong rabies neutralizing antibody titers. The antigen-specific immune responses were detectable for 1 year in all groups.

CONCLUSIONS

In summary, this study shows the longevity of the immune responses up to 365 days for a pentavalent vaccine-against Ebola virus, Sudan virus, Marburg virus, Lassa virus, and RABV-using a safe and effective vaccine platform.

Lyssavirus Vaccine with a Chimeric Glycoprotein Protects across Phylogroups

Rabies is nearly 100% lethal in the absence of treatment, killing an estimated 59,000 people annually. Vaccines and biologics are highly efficacious when administered properly. Sixteen rabies-related viruses (lyssaviruses) are similarly lethal, but some are divergent enough to evade protection from current vaccines and biologics, which are based only on the classical rabies virus (RABV). Here we present the development and characterization of LyssaVax, a vaccine featuring a structurally designed, functional chimeric glycoprotein (G) containing immunologically important domains from both RABV G and the highly divergent Mokola virus (MOKV) G. LyssaVax elicits high titers of antibodies specific to both RABV and MOKV Gs in mice. Immune sera also neutralize a range of wild-type lyssaviruses across the major phylogroups. LyssaVax-immunized mice are protected against challenge with recombinant RABV and MOKV. Altogether, LyssaVax demonstrates the utility of structural modeling in vaccine design and constitutes a broadened lyssavirus vaccine candidate.

Inactivated Rabies Virus-Based Ebola Vaccine Preserved by Vaporization Is Heat-Stable and Immunogenic Against Ebola and Protects Against Rabies Challenge

BACKGROUND

Ebola virus (EBOV) is a highly lethal member of the Filoviridae family associated with human hemorrhagic disease. Despite being a sporadic disease, it caused a large outbreak in 2014-2016 in West Africa and another outbreak recently in the Democratic Republic of Congo. Several vaccine candidates are currently in preclinical and clinical studies but none are stable without cold chain storage.

METHODS

We used preservation by vaporization (PBV), a novel processing technology to heat-stabilize FiloRab1 (inactivated rabies-based Ebola vaccine), a candidate Ebola vaccine, and stored the vials at temperatures ranging from 4°C to 50°C for 10 days to 12 months. We immunized Syrian hamsters with the best long-term stable FiloRab1 PBV vaccines and challenged them with rabies virus (RABV).

RESULTS

Syrian hamsters immunized with FiloRab1 PBV-processed vaccines stored at temperatures of 4°C and 37°C for 6 months, and at 50°C for 2 weeks, seroconverted against both RABV-G and EBOV-GP. Notably, all of the FiloRab1 PBV vaccines proved to be 100% effective in a RABV challenge model.

CONCLUSIONS

We successfully demonstrated that the FiloRab1 PBV vaccines are stable and efficacious for up to 6 months when stored at temperatures ranging from 4°C to 37°C and for up to 2 weeks at 50°C.

New developments in rabies vaccination

Current rabies vaccines are safe and, when administered properly, they are highly effective. In addition, they elicit long-lasting immunity, with virus-neutralising antibody titres persisting for years after vaccination. However, current regimens require multiple doses to achieve high neutralising titres and they are costly, which means that it is difficult for developing countries, where rabies deaths are highest, to implement widespread vaccination. New innovations are the only way to reduce rabies disease to acceptable rates. Numerous preclinical and clinical studies are under way, testing novel vaccines, adjuvants and injection methods. Research into the use of live vaccines and alternative vaccine vectors is ongoing, while attempts to develop DNA vaccines have so far failed to match the immunogenicity and neutralising capability of traditional vaccines. The development of molecular adjuvants that induce faster, stronger immune responses with less antigen has yielded exciting preclinical results and appears to edge us closer to a better rabies vaccine. However, steep challenges remain: molecular adjuvants require administration with live vaccines, and differences in species specificity of immune molecules complicate development. Over all, the array of research undertaken over the past decade is impressive and encouraging, but most new vaccines have yet to be tested in clinical trials, and the viability of such experimental vaccines in the global market remains to be seen. Only a vaccine that outperforms currently available vaccines in every area will have a chance at widespread adoption. Nevertheless, the authors are confident that some vaccine candidates will meet these criteria.

The spread and evolution of rabies virus: conquering new frontiers

Rabies is a lethal zoonotic disease that is caused by lyssaviruses, most often rabies virus. Despite control efforts, sporadic outbreaks in wildlife populations are largely unpredictable, underscoring our incomplete knowledge of what governs viral transmission and spread in reservoir hosts. Furthermore, the evolutionary history of rabies virus and related lyssaviruses remains largely unclear. Robust surveillance efforts combined with diagnostics and disease modelling are now providing insights into the epidemiology and evolution of rabies virus. The immune status of the host, the nature of exposure and strain differences all clearly influence infection and transmission dynamics. In this Review, we focus on rabies virus infections in the wildlife and synthesize current knowledge in the rapidly advancing fields of rabies virus epidemiology and evolution, and advocate for multidisciplinary approaches to advance our understanding of this disease.

Systematic review: Helicobacter pylori and the risk of upper gastrointestinal bleeding risk in patients taking aspirin

BACKGROUND

Aspirin is widely used to modify the risk of recurrent vascular events. It is, however, associated with increased upper gastrointestinal bleeding risk. The influence of Helicobacter pylori on this risk is uncertain.

AIM

To determine the influence of H. pylori on upper gastrointestinal bleeding risk in patients taking aspirin.

METHODS

MEDLINE and EMBASE databases were searched. All studies providing data regarding H. pylori infection in adults taking aspirin and presenting with upper gastrointestinal bleeding were included.

RESULTS

A total of 13 studies that included 1 case-control, 10 cohort studies and 2 randomized-controlled trials (RCTs) were analysed. The case-control study (n = 245) determined H. pylori to be a significant independent risk factor for upper gastrointestinal bleeding. The cohort studies were heterogeneous, varying in inclusion criteria, doses and duration of aspirin used, mode of H. pylori testing and causative GI pathology considered. Comprising 5465 patients, H. pylori infection was tested for in 163 (0.03%) aspirin users with upper gastrointestinal bleeding. The RCTs yielded no significant results.

CONCLUSIONS

The current data are not sufficient to allow meta-analyses. The widely held belief that H. pylori is a risk factor for upper gastrointestinal bleeding in regular aspirin users is not supported by the very limited evidence available.

A methanotrophic marine molluscan (bivalvia, mytilidae) symbiosis: mussels fueled by gas

An undescribed mussel (family Mytilidae), which lives in the vicinity of hydrocarbon seeps in the Gulf of Mexico, consumes methane (the principal component of natural gas) at a high rate. The methane consumption is limited to the gills of these animals and is apparently due to the abundant intracellular bacteria found there. This demonstrates a methane-based symbiosis between an animal and intracellular bacteria. Methane consumption is dependent on the availability of oxygen and is inhibited by acetylene. The consumption of methane by these mussels is associated with a dramatic increase in oxygen consumption and carbon dioxide production. As the methane consumption of the bivalve can exceed its carbon dioxide production, the symbiosis may be able to entirely satisfy its carbon needs from methane uptake. The very light (delta(13)C = -51 to -57 per mil) stable carbon isotope ratios found in this animal support methane (delta(13)C = -45 per mil at this site) as the primary carbon source for both the mussels and their symbionts.

Deep-sea hydrocarbon seep communities: evidence for energy and nutritional carbon sources

Mussels, clams, and tube worms collected in the vicinity of hydrocarbon seeps on the Louisiana slope contain mostly "dead" carbon, indicating that dietary carbon is largely derived from seeping oil and gas. Enzyme assays, elemental sulfur analysis, and carbon dioxide fixation studies demonstrate that vestimentiferan tube worms and three clam species contain intracellular, autotrophic sulfur bacterial symbionts. Carbon isotopic ratios of 246 individual animal tissues were used to differentiate heterotrophic (8(13)C = -14 to -20 per mil), sulfur-based (8(13)C = -30 to -42 per mil), and methane-based (8(13)C = <-40 per mil) energy sources. Mussels with symbiotic methanotrophic bacteria reflect the carbon isotopic composition of the methane source. Isotopically light nitrogen and sulfur confirm the chemoautotrophic nature of the seep animals. Sulfur-based chemosynthetic animals contain isotopically light sulfur, whereas methane-based symbiotic mussels more closely reflect the heavier oceanic sulfate pool. The nitrogen requirement of some seep animals may be supported by nitrogen-fixing bacteria. Some grazing neogastropods have isotopic values characteristic of chemosynthetic animals, suggesting the transfer of carbon into the background deep-sea fauna.

Mussel growth supported by methane as sole carbon and energy source

Symbioses between chemoautotrophic bacteria and several specialized marine invertebrates are well documented. However, none of these symbioses have been demonstrated to provide sufficient energy and carbon to the host to enable it to grow. Growth rates of seep mussels collected from hydrocarbon seeps off the coast of Louisiana were measured in a controlled environment where methane was the sole carbon and energy source. The growth rates increased to a maximum of 17.2 micrometers per day in response to methane and approached zero in the absence of methane. These mussels contain methanotrophic symbiotic bacteria in their gills, which suggests that these bacteria provide their hosts with a net carbon flux originating from methane.

Stable carbon isotopic evidence for carbon limitation in hydrothermal vent vestimentiferans

Stable carbon isotope composition (delta(13)C values) can be used to evaluate an animal's source of nutritional carbon. Most animals with chemoautotrophic endosymbionts have quite negative tissue delta(13)C values due to discrimination against (13)C associated with chemoautotrophic assimilation of inorganic carbon. However, the delta(13)C values of hydrothermal vent (HTV) vestimentiferans are significantly higher than the values reported for non-HTV vestimentiferans or other invertebrates with chemoautotrophic endosymbionts. Tissue delta(13)C values of two species of HTV vestimentiferans increase with increasing size of the animals. This relation supports the hypothesis that the relatively high delta(13)C values are the result of inorganic carbon limitation during carbon fixation. A more favorable relation between gas exchange and carbon fixation in the smaller individuals is expected, due to differences in the geometric scaling of gas-exchange surfaces and trophosome volume.

A paradox resolved: sulfide acquisition by roots of seep tubeworms sustains net chemoautotrophy

Vestimentiferan tubeworms, symbiotic with sulfur-oxidizing chemoautotrophic bacteria, dominate many cold-seep sites in the Gulf of Mexico. The most abundant vestimentiferan species at these sites, Lamellibrachia cf. luymesi, grows quite slowly to lengths exceeding 2 meters and lives in excess of 170-250 years. L. cf. luymesi can grow a posterior extension of its tube and tissue, termed a "root," down into sulfidic sediments below its point of original attachment. This extension can be longer than the anterior portion of the animal. Here we show, using methods optimized for detection of hydrogen sulfide down to 0.1 microM in seawater, that hydrogen sulfide was never detected around the plumes of large cold-seep vestimentiferans and rarely detectable only around the bases of mature aggregations. Respiration experiments, which exposed the root portions of L. cf. luymesi to sulfide concentrations between 51-561 microM, demonstrate that L. cf. luymesi use their roots as a respiratory surface to acquire sulfide at an average rate of 4.1 micromol x g(-1) x h(-1). Net dissolved inorganic carbon uptake across the plume of the tubeworms was shown to occur in response to exposure of the posterior (root) portion of the worms to sulfide, demonstrating that sulfide acquisition by roots of the seep vestimentiferan L. cf. luymesi can be sufficient to fuel net autotrophic total dissolved inorganic carbon uptake.

Hemoglobin from a deep-sea hydrothermal-vent copepod

Deep-sea hydrothermal-vent fauna live in a highly variable environment where oxygen levels can be very low, and carbon dioxide and sulfide can reach high concentrations (1). These conditions are harsh for most aerobic metazoans, yet copepods can be abundant at hydrothermal vents. Here we report the structure and functional properties of hemoglobin extracted from the copepod Benthoxynus spiculifer, which was found in large numbers in a paralvinellid/gastropod community collection made during a cruise to the Juan de Fuca Ridge in 1998. Although hemoglobin has been reported in some littoral copepods (2), this is the first study of the structure and functional properties of copepod hemoglobin. Hemoglobin represents about 60% of the total soluble proteins extracted from B. spiculifer, and although it imparts a red color to the copepod, it does not provide a significant storage pool of oxygen. It is a 208-kDa protein, composed of 14 globin chains--7 of 14.3 kDa and 7 of 15.2 kDa. The hemoglobin has a very high and temperature-sensitive oxygen affinity, with no cooperativity or Bohr effect. These properties are adaptive for an animal living in a low-oxygen environment in which the primary function of the hemoglobin is most likely oxygen acquisition to support aerobic respiration.

Metazoans in extreme environments: adaptations of hydrothermal vent and hydrocarbon seep fauna

Some of the most extreme environments where animals survive are associated with active vents and seeps in the deep sea. In addition to the extreme pressure, low temperatures, and lack of light that characterize the deep sea in general, a variety of other factors that are hostile to most animals prevail in these environments. Hydrothermal vent regions show extremes in temperature, areas of very low oxygen, and the presence of toxic hydrogen sulfide and heavy metals. Hydrocarbon seeps, though much cooler than vents, also have regions of very low oxygen and high hydrogen sulfide, as well as other potentially harmful substances such as crude oil and supersaturated brine. Specially adapted animals not only tolerate these conditions, they often thrive under them. In most cases this tolerance is due to a combination of physiological and behavioral adaptations that allow animals to avoid the extremes of their habitats and yet benefit from the chemoautotrophic production characteristic of these environments.

Methane ice worms: Hesiocaeca methanicola colonizing fossil fuel reserves

During a research cruise in July 1997 in the Gulf of Mexico we discovered a gas hydrate approximately 1 m thick and over 2 m in diameter which had recently breached the sea floor at a depth of 540 m. The hydrate surface visible from the submarine was considerably greater than that of any other reported hydrate. Two distinct color bands of hydrate were present in the same mound, and the entire exposed surface of the hydrate was infested (2500 individuals/m2) with 2 to 4 cm-long worms, since described as a new species, Hesiocaeca methanicola, in the polychaete family Hesionidae (Desbruyères and Toulmond 1998). H. methanicola tissue stable isotope values are consistent with a chemo-autotrophic food source. No evidence of chemo-autotrophic symbionts was detected, but geochemical data support the presence of abundant free living bacteria on the hydrate. The activities of the polychaetes, grazing on the hydrate bacteria and supplying oxygen to their habitats, appears to contribute to the dissolution of hydrates in surface sediments.

Herbal preparations: a primer for the aeromedical physician

PURPOSE

This study was an effort to identify the botanical preparations of potential risk to the aviator and aviation safety, and to ascertain whether aviators are using dietary supplements despite extensive educational efforts discouraging over-the-counter medication use. Herbal preparations may be used by nearly 20% of the adult population. Although the aviator population may be presumed to use them as well, the actual degree of use among aviators is unknown. Use of such substances as health promotion or therapeutic agents may provide health benefits, but may also carry risk. Military and civilian aviators are not currently required to disclose such use, nor are examiners obligated to inquire or counsel aviators about them. This paper examines the trends in post-mortem toxicological samples suggesting botanical preparation use, and develops a rational method for determining suitability for use by the aviator.

METHOD

The toxicological test results from 3177 mishap pilots performed at the Civil Aeromedical Institute from 1989-1997 were examined for the presence of substances suggesting botanical preparation use. The prevalence of positive test results for ephedrine among mishap pilots was compared with the prevalence of tests positive for chemically and biologically similar non-botanical substances among mishap pilots. A review of existing literature was also performed to identify substances posing possible risk to the aviator health or aviation safety.

RESULTS

Ephedrine was found to be the only substance routinely screened on toxicological specimens that was suitable for association with botanical substance utilization. The percent of specimens positive for ephedrine increased three- to four-fold while the percent of specimens positive for similar non-botanical substances decreased overall. The literature revealed sufficient evidence that a number of open market botanical agents are capable of causing incapacitation by cardiovascular or neuropsychiatric mechanisms, yet are legally permitted for use by aviators.

CONCLUSION

Aviators are using botanical products with increasing frequency, and many of those substances may pose significant risk of incapacitation, altered sensorium, or adverse health effects. The flight surgeon must be diligent in eliciting a history of use and assisting aviators to minimize personal risk and risks to flight safety. A rational approach to assessing risk is presented.

Roots as a site of hydrogen sulfide uptake in the hydrocarbon seep vestimentiferan Lamellibrachia sp

Vestimentiferan tubeworms have no mouth or gut, and the majority of their nutritional requirements are provided by endosymbiotic bacteria that utilize hydrogen sulfide oxidation to fix CO(2) into organic molecules. It has been assumed that all vestimentiferans obtain the sulfide, O(2) and CO(2) needed by the bacteria across the plume (gill) surface, but some live in locations where very little sulfide is available in the sea water surrounding the plume. We propose that at least some of these vestimentiferans can grow a posterior extension of their body and tube down into the sea-floor sediment, and that they can use this extension, which we call the ‘root’, to take up sulfide directly from the interstitial water. In this study of the vestimentiferan Lamellibrachia sp., found at hydrocarbon seeps in the Gulf of Mexico at depths of approximately 700 m, we measured seawater and interstitial sulfide concentrations in the hydrocarbon seep habitat, determined the structural characteristics of the root tube using transmission electron microscopy, characterized the biochemical composition of the tube wall, and measured the sulfide permeability of the root tube. We found that, while the sulfide concentration is less than 1 (μ)mol l(−)(1) in the sea water surrounding the gills, it can be over 1.5 mmol l(−)(1) at a depth of 10–25 cm in sediment beneath tubeworm bushes. The root tube is composed primarily of giant (β)-chitin crystallites (12–30 % of total mass) embedded in a protein matrix (50 % of total mass). Root tubes have a mean diameter of 1.4 mm, a mean wall thickness of 70 (μ)m and can be over 20 cm long. The tubeworm itself typically extends its body to the distal tip of the root tube. The root tube wall was quite permeable to sulfide, having a permeability coefficient at 20 degrees C of 0. 41×10(−)(3)cm s(−)(1), with root tube being 2.5 times more permeable to sulfide than trunk tube of the same diameter. The characteristics of the root suggest that it reaches down to the higher sulfide levels present in the deeper sediment and that it functions to increase the surface area available for sulfide uptake in a manner analogous to a respiratory organ.

Impairment of spermatogenesis in mice lacking a functional aromatase (cyp 19) gene

It is well established that spermatogenesis is controlled by gonadotrophins and testosterone. However, a role for estrogens in male reproduction recently was suggested in adult mice deficient in estrogen receptor alpha. These mice became infertile primarily because of an interruption of fluid reabsorption by the efferent ductules of the epididymis, thus leading to a disruption of the seminiferous epithelium [Hess, R. A., Bunick, D., Lee, K. H., Bahr, J., Taylor, J. A., Korach, K. S., and Lubahn, D. B. (1997) Nature (London) 390, 509-512]. Despite the demonstration of the aromatase enzyme, which converts androgens to estrogens, and estrogen receptors within the rodent seminiferous epithelium, the role of aromatase and estrogen in germ cell development is unknown. We have investigated spermatogenesis in mice that lack aromatase because of the targeted disruption of the cyp19 gene (ArKO). Male mice deficient in aromatase were initially fertile but developed progressive infertility, until their ability to sire pups was severely impaired. The mice deficient in aromatase developed disruptions to spermatogenesis between 4.5 months and 1 year, despite no decreases in gonadotrophins or androgens. Spermatogenesis primarily was arrested at early spermiogenic stages, as characterized by an increase in apoptosis and the appearance of multinucleated cells, and there was a significant reduction in round and elongated spermatids, but no changes in Sertoli cells and earlier germ cells. In addition, Leydig cell hyperplasia/hypertrophy was evident, presumably as a consequence of increased circulating luteinizing hormone. Our findings indicate that local expression of aromatase is essential for spermatogenesis and provide evidence for a direct action of estrogen on male germ cell development and thus fertility.

Assisted bibliotherapy: effective, efficient treatment for moderate anxiety problems

Specific psychological treatments of proven effectiveness for moderate anxiety disorders are not often easily accessible in general practice. In this study, selected patients were supported in learning skills to manage their symptoms. This approach was efficient, acceptable, and led to clinically significant symptom reduction for a high proportion of patients. This improvement was well sustained at three-month follow-up.

Characterization of mice deficient in aromatase (ArKO) because of targeted disruption of the cyp19 gene

The formation of estrogens from C19 steroids is catalyzed by aromatase cytochrome P450 (P450arom), the product of the cyp19 gene. The actions of estrogen include dimorphic anatomical, functional, and behavioral effects on the development of both males and females, considerations that prompted us to examine the consequences of deficiency of aromatase activity in mice. Mice lacking a functional aromatase enzyme (ArKO) were generated by targeted disruption of the cyp19 gene. Male and female ArKO mice were born with the expected Mendelian frequency from F1 parents and grew to adulthood. Female ArKO mice at 9 weeks of age displayed underdeveloped external genitalia and uteri. Ovaries contained numerous follicles with abundant granulosa cells and evidence of antrum formation that appeared arrested before ovulation. No corpora lutea were present. Additionally the stroma were hyperplastic with structures that appeared to be atretic follicles. Development of the mammary glands approximated that of a prepubertal female. Examination of male ArKO mice of the same age revealed essentially normal internal anatomy but with enlargement of the male accessory sex glands because of increased content of secreted material. The testes appeared normal. Male ArKO mice are capable of breeding and produce litters of approximately average size. Whereas serum estradiol levels were at the limit of detection, testosterone levels were elevated, as were the levels of follicle-stimulating hormone and luteinizing hormone. The phenotype of these animals differs markedly from that of the previously reported ERKO mice, in which the estrogen receptor alpha is deleted by targeted disruption.

Sulfide binding in the body fluids of hydrothermal vent alvinellid polychaetes

Dissolved H2S is a major environmental factor in hydrothermal vent ecosystems. In a study of adaptations to sulfide by alvinellid polychaetes, the sulfide-binding capacity of body fluids was examined in Paralvinella palmiformis from northeast Pacific ridges and Alvinella species from the East Pacific Rise. Sulfide concentrations in vascular blood and coelomic fluid of freshly collected animals were notably variable. Separation of P. palmiformis body-fluid components revealed that most sulfide (ca. 77%) was accumulated in the dissolved fraction. In P. palmiformis, both vascular blood and coelomic fluid could reversibly bind sulfide in vitro with a low affinity, saturating only at high dialysate concentrations (ca. 2 mmol L-1). No sulfide-binding activity was observed in the vascular blood from Alvinella species. A dissolved protein component of greater than 90 kDa appears to be involved in sulfide binding in Paralvinella, probably a vascular extracellular high-molecular-weight hemoglobin. Some sulfide may also adsorb onto a 15.38-kDa intracellular hemoglobin present in the coelomic erythrocyte fraction. In the absence of epibiotic bacteria, Paralvinella body fluids may function as a sulfide buffer to protect tissues from deleterious effects of sulfide exposure.

Aromatase expression in health and disease

Family 19 of the P450 superfamily is responsible for the conversion of C19 androgenic steroids to the corresponding estrogens, a reaction known as aromatization, since it involves conversion of the delta 4-3-one A-ring of the androgens to the corresponding phenolic A-ring characteristic of estrogens. Its members occur throughout the entire vertebrate phylum. The reaction mechanism of aromatase is very interesting from a chemical point of view and has been studied extensively; however, a detailed examination of structure-function relationships has not been possible due to lack of a crystal structure. Recent attempts to model the three-dimensional structure of aromatase have permitted a model that accounts for the reaction mechanism and predicts the location of aromatase inhibitors. The gene encoding human aromatase has been cloned and characterized and shown to be unusual compared to genes encoding other P450 enzymes, since there are a number of untranslated first exons that occur in aromatase transcripts in a tissue-specific fashion, due to differential splicing as a consequence of the use of tissue-specific promoters. Thus, expression in ovary utilizes a proximal promoter that is regulated primarily by cAMP. On the other hand, expression in placenta utilizes a distal promoter that is located at least 40 kb upstream of the start of transcription and that is regulated by retinoids. Other promoters are employed in brain and adipose tissue. In the latter case, class I cytokines such as IL-6 and IL-11 as well as TNF alpha are important regulatory factors. PGE2 is also an important regulator of aromatase expression in adipose mesenchymal cells via cAMP and PGE2 appears to be a major factor produced by breast tumors that stimulates estrogen biosynthesis in local mesenchymal sites. In all of the splicing events involved in the use of these various promoters, a common 3'-splice junction is employed that is located upstream of the start of translation; thus, the coding regions of the transcripts- and hence the protein-are identical regardless of the tissue site of expression; what differ in a tissue-specific fashion are the 5'-ends of the transcripts. This pattern of expression has great significance both from a phylogenetic and ontogenetic standpoint as well as for the physiology and pathophysiology of estrogen formation. Recently, a number of mutations of the aromatase gene have been described, which give rise to complete estrogen deficiency. In females this results in virilization in utero and primary amenorrhea with hypergonadotropic hypogonadism at the time of puberty. In men the most striking feature is continued linear bone growth beyond the time of puberty, delayed bone age, and failure of epiphyseal closure, thus indicating an important role of estrogens in bone metabolism in men. In both sexes the symptoms can be alleviated by estrogen administration.

Molecular basis of maple syrup urine disease: novel mutations at the E1 alpha locus that impair E1(alpha 2 beta 2) assembly or decrease steady-state E1 alpha mRNA levels of branched-chain alpha-keto acid dehydrogenase complex

We report the occurrence of three novel mutations in the E1 alpha (BCKDHA) locus of the branched-chain alpha-keto acid dehydrogenase (BCKAD) complex that cause maple syrup urine disease (MSUD). An 8-bp deletion in exon 7 is present in one allele of a compound-heterozygous patient (GM-649). A single C nucleotide insertion in exon 2 occurs in one allele of an intermediate-MSUD patient (Lo). The second allele of patient Lo carries an A-to-G transition in exon 9 of the E1 alpha gene. This missense mutation changes Tyr-368 to Cys (Y368C) in the E1 alpha subunit. Both the 8-bp deletion and the single C insertion generate a downstream nonsense codon. Both mutations appear to be associated with a low abundance of the mutant E1 alpha mRNA, as determined by allele-specific oligonucleotide probing. Transfection studies strongly suggest that the Y368C substitution in the E1 alpha subunit impairs its proper assembly with the normal E1 beta. Unassembled as well as misassembled E1 alpha and E1 beta subunits are degraded in the cell.

A syndrome of female pseudohermaphrodism, hypergonadotropic hypogonadism, and multicystic ovaries associated with missense mutations in the gene encoding aromatase (P450arom)

We report the features of a new syndrome of aromatase deficiency due to molecular defects in the CYP19 (P450arom) gene in a 46,XX female. At birth, the patient presented with a nonadrenal form of female pseudohermaphrodism. At 17 months of age, laparotomy revealed normal female internal genital structures; the histological appearance of the ovaries was normal. FSH concentrations were markedly elevated at 9.4 ng/mL LER 869, and estrone and estradiol levels were undetectable (< 37 pmol/L). By 14 yr of age, she had failed to exhibit breast development. The clitoris had enlarged to 4 x 2 cm, and pubic hair was Tanner stage IV. The plasma concentration of testosterone was elevated at 3294 pmol/L, as was androstenedione at 9951 pmol/L. Plasma estradiol levels were below 37 pmol/L. ACTH and dexamethasone tests indicated a nonadrenal source of testosterone and androstenedione. Plasma gonadotropin levels were in the castrate range. Pelvic sonography and magnetic resonance imaging showed multiple 4- to 6-cm ovarian cysts bilaterally. Despite increased circulating androgens and clitoral growth, the bone age was 10 yr at chronologic age 14 2/12 yr. Estrogen replacement therapy resulted in a growth spurt, breast development, menarche, suppression of gonadotropin levels, and resolution of the cysts. The clinical findings suggested the diagnosis of P450arom deficiency. Analyses of genomic DNA from ovarian fibroblasts demonstrated two single base changes in the coding region of the P450arom gene, one at 1303 basepairs (C-T), R435C, and the other at 1310 basepairs (G-A), C437Y, in exon 10. The molecular genetic studies indicate that the patient is a compound heterozygote for these mutations. Expression of these mutations showed that the R435C mutation had 1.1% the activity of the wild-type P450arom enzyme, whereas the C437Y mutation demonstrated no activity. The cardinal features of this syndrome are a consequence of P450arom deficiency: 1) the fetal masculinization in this syndrome can be ascribed to defective placental conversion of C19 steroids to estrogens, leading to exposure of the female fetus to excessive amounts of testosterone; 2) the pubertal failure, mild virilization, multicystic ovaries, and hyperstimulation of the ovaries by FSH and LH are the result of the inability of the ovary to aromatize testosterone and androstenedione to estrogens; and 3) the striking delay in bone age at 14 2/12 yr supports the notion that estrogens, in contrast to androgens, are the major sex steroid driving skeletal maturation during puberty. Familial P450arom deficiency, although rare, may be more common than previously suspected.(ABSTRACT TRUNCATED AT 400 WORDS)

Molecular basis of aromatase deficiency in an adult female with sexual infantilism and polycystic ovaries

We identified two mutations in the CYP19 gene responsible for aromatase deficiency in an 18-year-old 46,XX female with ambiguous external genitalia at birth, primary amenorrhea and sexual infantilism, and polycystic ovaries. The coding exons, namely exons II-X, of the CYP19 gene were amplified by PCR from genomic DNA and sequenced directly. Direct sequencing of the amplified DNA from the patient revealed two single-base changes, at bp 1303 (C-->T) and bp 1310 (G-->A) in exon X, which were newly found missense mutations and resulted in codon changes of R435C and C437Y, respectively. Subcloning followed by sequencing confirmed that the patient is a compound heterozygote. The results of restriction fragment length polymorphism analysis and direct sequencing of the amplified exon X DNA from the patient's mother indicate maternal inheritance of the R435C mutation. Transient expression experiments showed that the R435C mutant protein had approximately 1.1% of the activity of the wild type, whereas C437Y was totally inactive. Cysteine-437 is the conserved cysteine in the heme-binding region believed to serve as the fifth coordinating ligand of the heme iron. To our knowledge, this patient is the first adult to have described the cardinal features of a syndrome of aromatase deficiency. Recognition that such defects exist will lead to a better understanding of the role of this enzyme in human development and disease.

Occurrence of a 2-bp (AT) deletion allele and a nonsense (G-to-T) mutant allele at the E2 (DBT) locus of six patients with maple syrup urine disease: multiple-exon skipping as a secondary effect of the mutations

We have identified two novel mutant alleles in the transacylase (E2) gene of the human branched-chain alpha-keto acid dehydrogenase (BCKAD) complex in 6 of 38 patients with maple syrup urine disease (MSUD). One mutation, a 2-bp (AT) deletion in exon 2 of the E2 gene, causes a frameshift downstream of residue (-26) in the mitochondrial targeting presequence. The second mutation, a G-to-T transversion in exon 6 of the E2 gene, produces a premature stop codon at Glu-163 (E163*). Transfection of constructs harboring the E163* mutation into an E2-deficient MSUD cell line produced a truncated E2 subunit. However, this mutant E2 chain is unable to assemble into a 24-mer cubic structure and is degraded in the cell. The 2-bp (AT) deletion and the E163* mutant alleles occur in either the homozygous or compound-heterozygous state in the 6 of 38 unrelated MSUD patients studied. Moreover, an array of precise single- and multiple-exon deletions were observed in many amplified E2 mutant cDNAs. The latter results appear to represent secondary effects on RNA processing that are associated with the MSUD mutations at the E2 locus.

Hospital and Medicare financial performance under PPS, 1985-90

Although an increasing number of hospitals are reporting net losses from the Medicare prospective payment system (PPS) for inpatient care, overall hospital facility profit rates remain stable. Hospitals that reported net profits in the Medicare inpatient PPS sector in PPS 7 (1990) had smaller increases in Medicare expenses than hospitals that reported PPS losses in PPS 7. Medicare PPS inpatient net losses in PPS 7 were more than offset by non-Medicare net profits. Even though Medicare PPS revenues grew more slowly than the gross domestic product from 1985 to 1990, other hospital revenues grew more rapidly.

Trends in total hospital financial performance under the prospective payment system

In this article, the author examines trends in determinants of total hospital facility revenues, expenses, and net profits during the period 1977-89. Measures of change in transaction prices are developed, which enable an analysis of trends in real hospital outputs and total factor productivity. The main source of hospital spending growth in excess of the gross national product is identified as growth in hospital employee compensation.

Maple syrup urine disease in Mennonites. Evidence that the Y393N mutation in E1 alpha impedes assembly of the E1 component of branched-chain alpha-keto acid dehydrogenase complex

Maple Syrup Urine Disease (MSUD) in Mennonites is associated with homozygosity for a T to A transversion in the E1 alpha gene of the branched-chain alpha-keto acid dehydrogenase complex. This causes a tyrosine to asparagine substitution at position 393 (Y393N). To assess the functional significance of this missense mutation, we have carried out transfection studies using E1 alpha-deficient MSUD lymphoblasts (Lo) as a host. The level of E1 beta subunit is also greatly reduced in Lo cells. Efficient episomal expression in lymphoblasts was achieved using the EBO vector. The inserts employed were chimeric bovine-human cDNAs which encode mitochondrial import competent E1 alpha subunit precursors. Transfection with normal E1 alpha cDNA into Lo cells restored decarboxylation activity of intact cells. Western blotting showed that both E1 alpha and E1 beta subunits were markedly increased. Introduction of Y393N mutant E1 alpha cDNA failed to produce any measurable decarboxylation activity. Mutant E1 alpha subunit was expressed at a normal level, however, the E1 beta subunit was undetectable. These results provide the first evidence that Y393N mutation is the cause of MSUD. Moreover, this mutation impedes the assembly of E1 alpha with E1 beta into a stable alpha 2 beta 2 structure, resulting in the degradation of the free E1 beta subunit.

Occurrence of a Tyr393----Asn (Y393N) mutation in the E1 alpha gene of the branched-chain alpha-keto acid dehydrogenase complex in maple syrup urine disease patients from a Mennonite population

Maple syrup urine disease (MSUD) is caused by a deficiency in the mitochondrial branched-chain alpha-keto acid dehydrogenase complex. The incidence of MSUD in the Philadelphia Mennonites is 1/176 births resulting from consanguinity. In this study, we amplified cDNAs for the decarboxylase E1 alpha subunit of the branched-chain alpha-keto acid dehydrogenase complex from a classical MSUD patient and from an obligatory heterozygote of a Mennonite family by the PCR. Sequencing of the amplified cDNAs disclosed at codon 393 of the mature E1 alpha polypeptide a base substitution changing a tyrosine (encoded by TAC) to an asparagine residue (encoded by AAC), which is designated Y393N. A segment of the E1 alpha gene containing the 5' portion of exon 9 was amplified. Probing of the amplified genomic DNA with allele-specific oligonucleotide probes showed that the mutation in the E1 alpha gene was homozygous in six Mennonites affected with classical MSUD and was present in heterozygous carriers. The identification of the MSUD mutation in the Philadelphia Mennonites will facilitate diagnosis and carrier detection for this population.

Sulfide-Driven Autotrophic Balance in the Bacterial Symbiont-Containing Hydrothermal Vent Tubeworm, Riftia pachyptila Jones

Hydrothermal vent tubeworms, Riftia pachyptila Jones, were maintained alive and studied on board ship using flow-through pressure aquaria. Simultaneous measurements of O2, ΣCO2, ΣH2S fluxes showed that the intact symbioses reach maximum rates of uptake of ΣCO2 (>2 μmole g-1 h-1) at about 90 μM ΣH2S. Measurements were made of hemolymph and coelomic fluid ΣCO2, ΣH2S, thiosulfate, pH, and hemoglobin concentrations in worms kept under various conditions of O2 and ΣH2S. Normal hemolymph pH appears to be about 7.5 and is not affected by ΣH2S and ΣCO2 concentrations within the ranges observed. We conclude that Riftia is specialized to provide sulfide to its symbionts with minimal interaction of sulfide with the animal metabolism. The uptake of sulfide is apparently by diffusion into the hemolymph, facilitated by the sulfide-binding properties of the hemoglobins. Both ΣCO2 and PCO2 are elevated in the hemolymph above their levels in the medium, although they are reduced under autotrophic conditions. Thus inorganic carbon is apparently concentrated from the medium into the hemolymph by an unknown mechanism.

A 17-bp insertion and a Phe215----Cys missense mutation in the dihydrolipoyl transacylase (E2) mRNA from a thiamine-responsive maple syrup urine disease patient WG-34

We have amplified the cDNA for the transacylase (E2) subunit of the branched-chain alpha-ketoacid dehydrogenase (BCKAD) complex from a thiamine-responsive MSUD cell line (WG-34) by the polymerase chain reaction. Sequencing of the amplified WG-34 cDNA showed a 17-bp insertion (AAATACCTTGTTACCAG) apparently resulting from an aberrant splicing of the E2 gene, and a missense (T----G) mutation that changes Phe215 to Cys in the E2 subunit. The existence of these two mutations was confirmed by probing the amplified E2 cDNA or genomic DNA with allele-specific oligonucleotides. The above results support the thesis that the thiamine-responsive MSUD patient (WG-34) is a compound heterozygote at the E2 locus. The implication of the E2 mutations for the thiamine-responsiveness observed in this patient is discussed.

Physician charges and utilization trends

A synopsis of charge and payment trends of Medicare physicians and other noninstitutional suppliers of goods and services is provided in this article. Included are longitudinal variations in charges for services, trends in program expenditures, and patterns in beneficiary liabilities.

Medicare physician and hospital utilization and expenditure trends

During the period 1983-86, the period directly following implementation of the Medicare prospective payment system, inpatient hospital care declined. Concurrently, fee-for-service utilization rates for physicians and other noninstitutional suppliers of medical goods and services and for outpatient facility care rose. Medicare expenditures for physicians and other suppliers and for outpatient facility care paralleled changes in utilization. In 1987, the proportion of Medicare patients receiving inpatient hospital care stabilized, but the proportion receiving outpatient hospital care continued to increase.

Physician charges for surgical services under Medicare, by medical specialty: 1980 and 1985

Since 1980, a number of Medicare practice and utilization patterns have changed as a result of payment reform, certification of new types of providers, and changes in technology. The shift in physician surgical charges by specialty and by setting is examined in this article.

Trends in Medicare enrollee use of physician and supplier services, 1983-86

Beginning in 1984, the long-term trend of increasing utilization of inpatient hospital care by Medicare enrollees reversed. As Medicare patients increasingly received care in outpatient hospital facilities, ambulatory surgical centers, and physicians' offices, the structure of charges for physicians' services changed significantly. Medical services by physicians in inpatient hospitals declined rapidly. Surgical care for less life-threatening illnesses, such as eye conditions, moved from inpatient hospitals to outpatient facilities and physicians' charges derived from inpatient care was offset primarily by the increased proportion derived from physician care in outpatient facilities, mostly for surgery.

Medicare episodes of illnesses: a study of hospital, skilled nursing facility, and home health agency care

This paper analyzes charges incurred under the Medicare program for inpatient hospital, skilled nursing facility (SNF), and home health agency (HHA) care for 1976. This research was made possible through the construction of a new data set which links a beneficiary's use of these three services. Summary highlights reveal that an overwhelming majority of the 7.5 million Medicare episodes of illness do not involve post-hospital SNF or HHA care. Those episodes of illness that use only hospital care are substantially (53%) cheaper than all other episodes. A large percentage of these charge differences reflect the greater number of hospital days of care associated with post-hospital care services. However, an analysis of the beneficiaries' demographic characteristics suggests that persons who use post-hospital care generally differ from those who receive only hospital care. We found that persons who use post-hospital SNF or HHA, or both types of care are likely to be female, to have cancer, diabetes, fractured bones or a central nervous or vascular system disease, and to be older than persons who do not use these types of care. The data also show that a beneficiary's area of residence greatly influences the amount and types of care received. Persons who reside in the New England, Middle Atlantic and Pacific Divisions are more likely to receive post-hospital care services than person who live elsewhere in the United States. These persons also incur among the highest per capita institutional charges in the United States. Part of this variation in institutional charges per capita is explained by the high input price index found in these areas, and in some cases by the high quantity of services index.

Differences by age groups in health care spending

This paper presents differences by age in health care spending by type of expenditure and by source of funds through 1978. Use of health care services generally increases with age. The average health bill reached $2,026 for the aged in 1978, $764 for the intermediate age group, and $286 for the young. Biological, demographic, and policy factors determine each age group's share of health spending. Public funds financed over three-fifths of the health expenses of the aged, with Medicare and Medicaid together accounting for 58 percent. Most of the health expenses of the young age groups were paid by private sources.

Age differences in health care spending, fiscal year 1977

This report of health care spending in fiscal year 1977 reveals that of the $142.6 billion spent by the Nation for personal health care in fiscal year 1977, 29 percent was spent for those aged 65 or older, 59 percent for those aged 19-64, and 13 percent for those below age 19. The average health bill reached $1,745 for the aged, $661 for the intermediate age group, and $253 for the young. Public funds financed 67 percent of the health expenses of the aged, with Medicare and Medicaid together accounting for 61 percent. More than two-thirds of the health expenses of the young and 71 percent of the expenses of those aged 19-64 were paid by private sources. Third-party payments met 68 percent of the health expenditures of all those under age 65.

National health expenditures, fiscal year 1977

The Nation spent $163 billion for health care in fiscal year 1977 or $737 per person, according to preliminary figures compiled by the Health Care Financing Administration. This figure was 12 percent higher than spending for such purposes in the previous 12 months and represented an 8.8-percent share of the GNP. Public spending, which financed 42 percent of all health care in 1977, increased 11 percent while private spending rose 13 percent. Spending for hospital care went up 14 percent to $68.4 billion, and the total spent for physicians' services ($32.2 billion) reflected a 13-percent rise. Third-party payments financed 70 percent of all personal health care in the country.

Age differences in health care spending, fiscal year 1976

Of the $120.4 billion spent by the Nation for personal health care in fiscal year 1976, 29% was spent for those aged 65 or older, 15% for those under age 19, and the remaining 56% for those aged 19-64. The average health bill reached $1,521 for the aged, $547 for the intermediate age group, and $249 for the young. Public funds financed 68% of the health expenses of the aged with Medicare and Medicaid together accounting for 59%. Private sources paid 74% of the health expenses of the young and 70% of the expenses of those aged 19-64. Third-party payments met 65% of the health expenditures of all those under age 65.