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Anna M Wahl,1 Daniel Bidstrup,1 Isabel G Smidt-Nielsen,1 Mads U Werner,2 Ole Hyldegaard,1,3 Per Rotbøll-Nielsen21Hyperbaric Unit, Department of Anesthesia, Head and Orthopedic Center, Rigshospitalet, Copenhagen University Hospitals, Copenhagen, Denmark; 2Multidisciplinary Pain Center, Neuroscience Center, Rigshospitalet, Copenhagen University Hospitals, Copenhagen, Denmark; 3Institute of Clinical Medicine, University of Copenhagen, Copenhagen, DenmarkPurpose: Animal studies have demonstrated anti-inflammatory, and anti-nociceptive properties of hyperbaric oxygen therapy (HBOT). However, physiological data are scarce in humans. In a recent experimental study, the authors used the burn injury (BI) model observing a decrease in secondary hyperalgesia areas (SHA) in the HBOT-group compared to a control-group. Surprisingly, a long-lasting neuroplasticity effect mitigating the BI-induced SHA-response was seen in the HBOT-preconditioned group. The objective of the present study, therefore, was to confirm our previous findings using an examiner-blinded, block-randomized, controlled, crossover study design.Patients and methods: Nineteen healthy subjects attended two BI-sessions with an inter-session interval of ≥28 days. The BIs were induced on the lower legs by a contact thermode (12.5 cm,2 47C°, 420 s). The subjects were block-randomized to receive HBOT (2.4 ATA, 100% O2, 90 min) or ambient conditions ([AC]; 1 ATA, 21% O2), dividing cohorts equally into two sequence allocations: HBOT-AC or AC-HBOT. All sensory assessments performed during baseline, BI, and post-intervention phases were at homologous time points irrespective of sequence allocation. The primary outcome was SHA, comparing interventions and sequence allocations.Results: Data are mean (95% CI). During HBOT-sessions a mitigating effect on SHA was demonstrated compared to AC-sessions, ie, 18.8 (10.5–27.0) cm2 vs 32.0 (20.1–43.9) cm2 (P=0.021), respectively. In subjects allocated to the sequence AC-HBOT a significantly larger mean difference in SHA in the AC-session vs the HBOT-session was seen 25.0 (5.4–44.7) cm2 (P=0.019). In subjects allocated to the reverse sequence, HBOT-AC, no difference in SHA between sessions was observed (P=0.55), confirming a preconditioning, long-lasting (≥28 days) effect of HBOT.Conclusion: Our data demonstrate that a single HBOT-session compared to control is associated with both acute and long-lasting mitigating effects on BI-induced SHA, confirming central anti-inflammatory, neuroplasticity effects of hyperbaric oxygen therapy.Keywords: burns, hyperbaric oxygenation, inflammation, pathophysiology, secondary hyperalgesia

Currently, all salivary ducts (intercalated, striated and collecting) are assumed to function broadly in a similar manner, reclaiming ions that were secreted by the secretory acinar cells while preserving fluid volume and delivering saliva to the oral cavity. Nevertheless, there has been minimal investigation into the structural and functional differences between distinct types of salivary duct cells. Therefore, in this study, the expression profile of proteins involved in stimulus-secretion coupling, as well as the function of the intercalated duct (ID) and striated duct cells, was examined. Particular focus was placed on defining differences between distinct duct cell populations. To accomplish this, immunohistochemistry and in situ hybridization were utilized to examine the localization and expression of proteins involved in reabsorption and secretion of ions and fluid. Further, in vivo calcium imaging was employed to investigate cellular function. Based on the protein expression profile and functional data, marked differences between the IDs and striated ducts were observed. Specifically, the ID cells express proteins native to the secretory acinar cells while lacking proteins specifically expressed in the striated ducts. Further, the ID and striated duct cells display different calcium signalling characteristics, with the IDs responding to a neural stimulus in a manner similar to the acinar cells. Overall, our data suggest that the IDs have a distinct role in the secretory process, separate from the reabsorptive striated ducts. Instead, based on our evidence, the IDs express proteins found in secretory cells, generate calcium signals in a manner similar to acinar cells, and, therefore, are likely secretory cells. KEY POINTS: Current studies examining salivary intercalated duct cells are limited, with minimal documentation of the ion transport machinery and the overall role of the cells in fluid generation. Salivary intercalated duct cells are presumed to function in the same manner as other duct cells, reclaiming ions, maintaining fluid volume and delivering the final saliva to the oral cavity. Here we systematically examine the structure and function of the salivary intercalated duct cells using immunohistochemistry, in situ hybridization and by monitoring in vivo Ca 2+ dynamics. Structural data revealed that the intercalated duct cells lack proteins vital for reabsorption and express proteins necessary for secretion. Ca 2+ dynamics in the intercalated duct cells were consistent with those observed in secretory cells and resulted from GPCR-mediated IP 3 production., (© 2023 The Authors. The Journal of Physiology © 2023 The Physiological Society.)

Mutations in all subtypes of the inositol 1,4,5-trisphosphate receptor Ca 2+ release channel are associated with human diseases. In this report, we investigated the functionality of three neuropathy-associated missense mutations in IP 3 R3 (V615M, T1424M, and R2524C). The mutants only exhibited function when highly over-expressed compared to endogenous hIP 3 R3. All variants resulted in elevated basal cytosolic Ca 2+ levels, decreased endoplasmic reticulum Ca 2+ store content, and constitutive store-operated Ca 2+ entry in the absence of any stimuli, consistent with a leaky IP 3 R channel pore. These variants differed in channel function; when stably over-expressed the R2524C mutant was essentially dead, V615M was poorly functional, and T1424M exhibited activity greater than that of the corresponding wild-type following threshold stimulation. These results demonstrate that a common feature of these mutations is decreased IP 3 R3 function. In addition, these mutations exhibit a novel phenotype manifested as a constitutively open channel, which inappropriately gates SOCE in the absence of stimulation., Competing Interests: The authors of this work have no competing interests to disclose., (© 2022 The Author(s).)

The cytosolic concentration of free calcium ions ([Ca2+]) is an important intracellular messenger in most cell types, and the spatial distribution of [Ca2+] is often critical. In a salivary gland acinar cell, a polarised epithelial cell, whose principal function is to transport water and thus secrete saliva, [Ca2+] controls the secretion of primary saliva, but increases in [Ca2+] are localised to the apical regions of the cell. Hence, any quantitative explanation of how [Ca2+] controls saliva secretion must take into careful account the spatial distribution of the various Ca2+ sources, Ca2+ sinks, and Ca2+-sensitive ion channels. Based on optical slices, we have previously constructed anatomically accurate three-dimensional models of seven salivary gland acinar cells, and thus shown that a model in which Ca2+ responses are confined to the apical regions of the cell is sufficient to provide a quantitative and predictive explanation of primary saliva secretion. However, reconstruction of such anatomically accurate cells is extremely time consuming and inefficient. Here, we present an alternative, mostly automated method of constructing three-dimensional cells that are approximately anatomically accurate and show that the new construction preserves the quantitative accuracy of the model.

People in artisanal and small-scale gold mining (ASGM) areas are frequently exposed to high levels of mercury (Hg). Hg analyses in urine and whole blood are the gold standard of biomonitoring, although this may not provide sufficient information about the source of exposure, e.g., due to the use of Hg for gold extraction or due to nutrition. To evaluate, whether the pharmacokinetic properties of individual Hg species may be useful for exposure assessment, we determined the Hg levels in different blood components from 199 participants. Therefore, whole blood was centrifuged on-site to yield erythrocytes and plasma. Globin was isolated from the erythrocytes by precipitation with ethyl acetate. Albumin was isolated from plasma by gradual precipitation with saturated ammonium sulfate solution. Hg levels in all samples were determined by using a direct Hg analyzer. Median Hg levels for whole blood, erythrocytes, and plasma were 2.7, 3.7, and 1.3 μg/l, respectively. In globin and albumin, median Hg levels were 10.3 and 7.9 μg/kg, respectively. The distribution of Hg was strongly correlated with whole blood Hg levels (p < 0.01) and the time between the last use of Hg and the date of the participation (p < 0.01). The results suggest that the distribution of Hg in blood is substantially affected by the extent and the frequency of the exposure to elemental Hg. Therefore, the analysis of Hg in erythrocytes and plasma may be a valuable tool for Hg exposure assessment in ASGM areas., (© 2021. The Author(s).)

People living and working in artisanal and small-scale gold mining (ASGM) areas are frequently exposed to elemental mercury (Hg), which is used for gold extraction. However, additional exposure to other toxic metals such as arsenic (As), cadmium (Cd) and lead (Pb) may result from mining-related activities and could be ingested via dust, water or food. In these areas, only limited biomonitoring data is available for toxic metals other than Hg. In particular, data about the exposure to As, Cd and Pb is unavailable for the Zimbabwean population. Therefore, we conducted a cross-sectional study in two ASGM areas in Zimbabwe to evaluate the internal exposure to these metals. In total, urine and blood samples from 207 people that identified themselves as miners were collected and analysed for As and Cd in urine as well as Pb in blood by GF-AAS. Median levels (interquartile ranges in μg/l) of As and Pb were 9.7 μg/l (4.0, 18.5) and 19.7 μg/l (12.5, 34.5), respectively. The 25th percentile and the median for Cd were below the limit of detection (0.5 μg/l); the 75th percentile was at 0.9 μg/l. The results were compared to reference values found for the general population in the USA and Germany, and a significant number of participants exceeded these values (As, 33 %; Cd, 27 %; Pb, 32 %), indicating a relevant exposure to toxic metals. Although not representative for the Zimbabwean population, our results demonstrate that the exposure to toxic metals is relevant for the public health in Zimbabwe and requires further investigation., (© 2021. The Author(s).)

Salivary fluid secretion involves an intricate choreography of membrane transporters to result in the trans-epithelial movement of NaCl and water into the acinus lumen. Current models are largely based on experimental observations in enzymatically isolated cells where the Ca 2+ signal invariably propagates globally and thus appears ideally suited to activate spatially separated Cl and K channels, present on the apical and basolateral plasma membrane, respectively. We monitored Ca 2+ signals and salivary secretion in live mice expressing GCamp6F, following stimulation of the nerves innervating the submandibular gland. Consistent with in vitro studies, Ca 2+ signals were initiated in the apical endoplasmic reticulum. In marked contrast to in vitro data, highly localized trains of Ca 2+ transients that failed to fully propagate from the apical region were observed. Following stimuli optimum for secretion, large apical-basal gradients were elicited. A new mathematical model, incorporating these data was constructed to probe how salivary secretion can be optimally stimulated by apical Ca 2+ signals., Competing Interests: TT, AW, KH, TN, JR, JS, DY No competing interests declared, (© 2021, Takano et al.)

Introduction: This study aimed to assess the capability of a pulse CO-oximeter to continuously monitor carboxyhemoglobin (COHb) during hyperbaric oxygen (HBO2) therapy. We estimated limits of agreement (LOA) between blood gas analysis and pulse CO-oximeter for COHb during HBO2 therapy in patients suffering from acute CO poisoning. Furthermore, we did a medicotechnical evaluation of the pulse CO-oximeter in hyperbaric conditions., Methods: We conducted a prospective, non-clinical, observational study in which we included n=10 patients with acute CO poisoning referred for HBO2 therapy. We did five repeated measurements of COHb for each patient during the HBO2 therapy. Bland-Altman analysis for multiple observations per individual was used to assess the agreement. The a priori LOA was ±6% for COHb. For the medicotechnical evaluation continuous measurements were obtained throughout each complete HBO2 therapy. The measurements were visually inspected and evaluated., Results: The Bland-Altman analysis showed that the pulse CO-oximeter overestimated COHb by 2.9 % [±1.0%] and the LOA was ±7.3% [±1.8%]. The continuous measurements by pulse CO-oximetry showed fluctuating levels of COHb and summarized saturations reached levels above 100%. Measurements were not affected by changes in pressure., Conclusion: To our knowledge, this study is the first to assess LOA and demonstrate use of a non-invasive method to measure COHb during HBO2 therapy. The pulse CO-oximeter performed within the manufactures reported LOA (±6%) despite hyperbaric conditions and was unaffected by changes in pressure. However, summarized saturations reached levels above 100%., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Middle ear barotrauma (MEB) is a common complication of hyperbaric oxygen (HBO2) therapy. It has been reported in more than 40% of HBO2 treatments and can interrupt the sequence of HBO2. MEB may lead to pain, tympanic membrane rupture, and even hearing loss. The aim of this study was to determine if pretreatment with intranasal fluticasone and oxymetazoline affected the incidence of MEB. We conducted a retrospective chart review of subjects undergoing HBO2 at our institution between February 1, 2014, and May 31, 2019. Subjects in the fluticasone/oxymetazoline (FOT) treatment group used intranasal fluticasone 50 mcg two times per day and oxymetazoline 0.05% one spray two times per day beginning 48 hours prior to initial HBO2. Oxymetazoline was discontinued after four days. Fluticasone was continued for the duration of HBO2 therapy. A total of 154 unique subjects underwent 5,683 HBO2 treatments: 39 unique subjects in the FOT group underwent 1,501 HBO2; 115 unique subjects in the nFOT (no oxymetazoline or fluticasone treatment) group underwent 4,182 HBO2 treatments. The incidence of MEB was 15.4% in the FOT group and 16.2% in the nFOT group. This was not a statistically significant difference (OR = 0.77; p = 0.636). Treatment pressure, age over 65 years, male sex, and BMI were not associated with a difference in MEB incidence. In summary, pretreatment with intranasal oxymetazoline and fluticasone in patients undergoing HBO2 did not significantly reduce MEB. More investigation with larger numbers of participants and prospective studies could further clarify this issue., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

The inositol 1,4,5-trisphosphate (IP 3 ) receptors (IP 3 Rs), which form tetrameric channels, play pivotal roles in regulating the spatiotemporal patterns of intracellular calcium signals. Mutations in IP 3 Rs have been increasingly associated with many debilitating human diseases such as ataxia, Gillespie syndrome, and generalized anhidrosis. However, how these mutations affect IP 3 R function, and how the perturbation of as-sociated calcium signals contribute to the pathogenesis and severity of these diseases remains largely uncharacterized. Moreover, many of these diseases occur as the result of autosomal dominant inheritance, suggesting that WT and mutant subunits associate in heterotetrameric channels. How the in-corporation of different numbers of mutant subunits within the tetrameric channels affects its activities and results in different disease phenotypes is also unclear. In this report, we investigated representative disease-associated missense mutations to determine their effects on IP 3 R channel activity. Additionally, we designed concatenated IP 3 R constructs to create tetrameric channels with a predefined subunit composition to explore the functionality of heteromeric channels. Using calcium imaging techniques to assess IP 3 R channel function, we observed that all the mutations studied resulted in severely attenuated Ca 2+ release when expressed as homotetramers. However, some heterotetramers retained varied degrees of function dependent on the composition of the tetramer. Our findings suggest that the effect of mutations depends on the location of the mutation in the IP 3 R structure, as well as on the stoichiometry of mutant subunits assembled within the tetrameric channel. These studies provide insight into the pathogenesis and penetrance of these devastating human diseases., Competing Interests: Conflict of interest—The authors declare no conflicts of interest in regards to the content of this manuscript., (© 2020 Terry et al.)

Cytoplasmic Ca 2+ is a pivotal regulator of IP 3 R activity. It is however controversial whether the [Ca 2+ ] in the Endoplasmic Reticulum lumen also directly regulates channel function. We highlight a recent paper that demonstrates that luminal [Ca 2+ ] potently inhibits IP 3 R activity. This regulation occurs indirectly by an interaction mediated through a binding partner, likely Annexin 1A., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Introduction: Treatment of diabetic foot ulcers is complex and often protracted. Hyperbaric oxygen treatment (HBOT) improves wound healing in diabetic ulcers and serves as an important adjunct to regular diabetic wound care. Endothelial dysfunction plays a central role in diabetes-related vascular complications and may be evaluated by a non-invasive technique called peripheral arterial tonometry which measures a reactive hyperaemia index (RHI). We hypothesized that endothelial function measured by peripheral arterial tonometry is impaired in diabetic foot ulcer patients and that HBOT might improve endothelial function., Methods: Endothelial function was prospectively assessed by peripheral arterial tonometry in 22 subjects with diabetic foot ulcers and 17 subjects without diabetes during courses of HBOT. Endothelial function was evaluated before first (baseline) and 30th treatments, and at 90-day follow-up. Serum insulin growth factor-I (IGF-I) concentrations were determined by immunoassay. Results were compared to 23 healthy subjects., Results: No baseline differences were found in endothelial function between subjects with diabetes, HBOT patients without-diabetes and healthy control subjects (RHI; 1.26, 1.61 and 1.81, respectively). No significant changes in RHI were found in patients with (P = 0.17) or without (P = 0.30) diabetes during courses of HBOT. At 90-day follow-up IGF-I was significantly reduced in the subjects with diabetes (P = 0.001) and unchanged in the group without diabetes (P = 0.99)., Conclusions: We found no significant differences in RHI between subjects with diabetic foot ulcers and patients without diabetes, nor improvement in endothelial function assessed by peripheral arterial tonometry during courses of HBOT., (Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.)

Background: The objectives of this study were to identify loci, positional candidate genes, gene-sets, and pathways associated with spontaneous abortion (SA) in cattle and compare these results with previous human SA studies to determine if cattle are a good SA model for humans. Pregnancy was determined at gestation day 35 for Holstein heifers and cows. Genotypes from 43,984 SNPs of 499 pregnant heifers and 498 pregnant cows that calved at full term (FT) were compared to 62 heifers and 28 cows experiencing SA. A genome-wide association analysis, gene-set enrichment analysis-single nucleotide polymorphism, and ingenuity pathway analysis were used to identify regions, pathways, and master regulators associated with SA in heifers, cows, and a combined population., Results: Twenty-three loci and 21 positional candidate genes were associated ( p < 1 × 10 -5 ) with SA and one of these (KIR3DS1) has been associated with SA in humans. Eight gene-sets (NES > 3.0) were enriched in SA and one was previously reported as enriched in human SA. Four master regulators ( p < 0.01) were associated with SA within two populations., Conclusions: One locus associated with SA was validated and 39 positional candidate and leading-edge genes and 2 gene-sets were enriched in SA in cattle and in humans.

Background: The nitric oxide system could play an important role in the pathophysiology related to necrotizing soft tissue infection (NSTI). Accordingly, we investigated the association between plasma nitrite level at admission and the presence of septic shock in patients with NSTI. We also evaluated the association between nitrite, asymmetric dimethylarginine (ADMA), L-arginine, L-arginine/ADMA ratio, and outcome., Methods: We analyzed plasma from 141 NSTI patients taken upon hospital admission. The severity of NSTI was assessed by the presence of septic shock, Simplified Acute Physiology Score (SAPS) II, Sepsis-Related Organ Failure Assessment (SOFA) score, use of renal replacement therapy (RRT), amputation, and 28-day mortality., Results: No difference in nitrite levels was found between patients with and without septic shock (median 0.82 μmol/L [interquartile range (IQR) 0.41-1.21] vs. 0.87 μmol/L (0.62-1.24), P = 0.25). ADMA level was higher in patients in need of RRT (0.64 μmol/L (IQR 0.47-0.90) vs. (0.52 μmol/L (0.34-0.70), P = 0.028), and ADMA levels correlated positively with SAPS II (rho = 0.32, P = 0.0002) and SOFA scores (rho = 0.22, P = 0.01). In a logistic regression analysis, an L-arginine/ADMA ratio below 101.59 was independently associated with 28-day mortality, odds ratio 6.03 (95% confidence interval, 1.41-25.84), P = 0.016. None of the other analyses indicated differences in the NO system based on differences in disease severity., Conclusions: In patients with NSTI, we found no difference in baseline nitrite levels according to septic shock. High baseline ADMA level was associated with the use of RRT and patients with a low baseline L-arginine/ADMA ratio were at higher risk of dying within 28 days after hospital admission.

Background: Septic shock remains a leading cause of death worldwide. Hyperbaric oxygen treatment (HBO 2 ) has been shown to alter the inflammatory response during sepsis and to reduce mortality. A therapeutic window of HBO 2 treatment has been demonstrated experimentally, but optimal timing remains uncertain. We investigated the effects of 24 h delayed normobaric oxygen (NBO 2 ) and HBO 2 treatment on the endogenous production of the inflammatory markers interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-10, and on mortality in rats with cecal ligation and puncture (CLP) induced sepsis., Method: Fifty-five male Sprague-Dawley rats underwent CLP and were randomized to the following groups: 1) HBO 2 2.5 bar absolute pressure (p abs ); 2) NBO 2 1.0 bar p abs ; 3) Control (no-treatment), and they were individually monitored for 72 h with intermittent blood sampling., Results: IL-6, TNF-α, and IL-10 were increased 24 h after the procedure, and IL-6 was significantly higher in non-survivors than in survivors. The level of IL-10 was significantly higher at hour 48 in the HBO 2 group compared to control ( p  = 0.01), but this was not the case at other time points. No other significant differences in cytokine levels were found for any group comparisons. Delayed NBO 2 and HBO 2 treatment failed to change the mortality in the animals., Conclusion: High levels of IL-6 in non-surviving animals with sepsis suggest that IL-6 is a potential biomarker. We found a significantly higher concentration of IL-10 in the HBO 2 group at hour 48 vs. control animals. However, 24 h-delayed treatment with HBO 2 did not change the levels of pro-inflammatory cytokines and survival, suggesting that earlier intervention may be required to obtain an anti-inflammatory effect.

In the medical domain, data quality is very important. Since requirements and data change frequently, continuous and sustainable monitoring and improvement of data quality is necessary. Working together with managers of medical centers, we developed an architecture for a data quality monitoring system. The architecture enables domain experts to adapt the system during runtime to match their specifications using a built-in rule system. It also allows arbitrarily complex analyses to be integrated into the monitoring cycle. We evaluate our architecture by matching its components to the well-known data quality methodology TDQM.

This is the first study to examine the relationship between acculturation and alcohol use by gender and ethnicity using a nationally representative sample of Hispanic and non-Hispanic white adolescents. Specifically, we use data from the National Longitudinal Study of Adolescent Health (Add Health) to explore alcohol use and binge drinking for a sample that includes 6792 non-Hispanic whites, 910 Mexican Americans, 290 Cuban Americans, and 336 Puerto Ricans. Bivariate results reveal significant gender differences in alcohol use among first generation Mexican American, first generation Puerto Rican, and second generation Cuban American adolescents. In addition, these results indicate binge drinking differs significantly by gender among first generation Mexican American, first generation Cuban American, third plus generation Puerto Rican, and third plus generation non-Hispanic white adolescents. Multivariate logistic regression reveals that gender also moderates the effect of acculturation as well as ethnicity on alcohol use and abuse. Among both males and females, first generation immigrants are significantly less likely than third plus generation immigrants to use alcohol and binge drink while selective acculturation significantly reduces the odds of both behaviors. However, the effects of immigrant generation and selective acculturation on binge drinking are larger for females. Further, the trajectories that alcohol use and binge drinking follow with acculturation differ significantly by gender and ethnicity. These results reaffirm the need to further develop theoretical models and intervention strategies that are both gender-specific and culturally-specific, targeting high risk groups in particular in these efforts.

Do alcohol use and binge drinking among Latina/o adolescents increase in the second and third generation? This study explores generational differences in alcohol use behaviors for three Latina/o ethnic groups. Using data from the National Longitudinal Study of Adolescent Health on 1504 Latina/o adolescents in secondary school, we found that the factors associated with alcohol use behaviors differed across the Latina/o groups. For Mexican and Cuban adolescents, but not Puerto Ricans, immigrant generation was associated with alcohol use. For Mexican, but not Cuban adolescents, acculturation mediated the effect of immigrant generation on alcohol use behaviors. Although generally social capital and a co-ethnic presence were protective factors against alcohol use behaviors, we found that some forms of social capital were actually risk factors for Cubans and Puerto Ricans. Our results provide support for segmented-assimilation theory.

Parasitic helminths induce chronic infections in their hosts although, with most human helminthiases, protective immunity gradually develops with age or exposure of the host. One exception is infection with the human hookworm, Necator americanus, where virtually no protection ensues over time. Such observations suggest these parasites have developed unique mechanisms to evade host immunity, leading us to investigate the role of the excretory/secretory (ES) products of adult N. americanus in manipulating host immune responses. Specifically, we found that a protein(s) from ES products of adult N. americanus bound selectively to mouse and human NK cells. Moreover, incubation of purified NK cells with N. americanus ES products stimulated the production of augmented (4- to 30-fold) levels of IFN-gamma. This augmentation was dependent on the presence of both IL-2 and IL-12 and was endotoxin-independent. This is the first report of a pathogen protein that binds exclusively to NK cells and the first report of a nematode-derived product that induces abundant levels of cytokines from NK cells. Such an interaction could provide a means of cross-regulating deleterious Th2 immune responses in the host, thereby contributing to the long-term survival of N. americanus.

Plasmodium (Novyella) juxtanucleare is a widely distributed parasite that primarily infects chickens (Gallus gallus domesticus). All species of Novyella are characterized by very small schizonts, which in the case of P. juxtanucleare are always found juxtaposed to the erythrocyte nucleus, hence its name. Nearly complete small-subunit ribosomal RNA sequences have been obtained from 2 isolates of this species, and comparisons with other Plasmodium species have been made. Phylogenetic analysis reveals that this parasite is closely related to other avian-infecting Plasmodium species and that molecular relationships among the avian-infecting plasmodia do not correspond to their morphology-based subgeneric classifications.

Gene trees of Plasmodium species have been reported for the nuclear encoded genes (e.g. the Small Subunit rRNA) and a mitochondrial encoded gene, cytochrome b. Here, we have analyzed a plastid gene coding for caseinolytic protease ClpC, whose structure, function and evolutionary history have been studied in various organisms. This protein possesses a 220-250 amino acid long AAA domain (ATPases associated with a variety of cellular activities) that belongs to the Walker super family of ATPases and GTPases. We have sequenced the AAA motif of this gene, encoding the protein from nine different species of Plasmodium infecting rodents, birds, monkeys, and humans. The codon usage and GC content of each gene were nearly identical in contrast to the widely varying nucleotide composition of genomic DNAs. Phylogenetic trees derived from both DNA and inferred protein sequences have consistent topologies. We have used the ClpC sequence to analyze the phylogenetic relationship among Plasmodium species and compared it with those derived from mitochondrial and genomic sequences. The results corroborate well with the trees constructed using the mitochondrially encoded cytochrome b. However, an important element distinguishes the trees: the placement of Plasmodium elongatum near the base of the plastid tree, indicating an ancient lineage of parasites in birds that branches from the tree prior to other lineages of avian malaria and the human parasite, P. falciparum.

In an experimental model of arthritis, increased leukocyte adhesion is associated with the evolution of acute and chronic synovial inflammation. Whereas peripheral blood mononuclear cells (PBMC) from control animals bind minimally to fibronectin matrices, PBMC from animals receiving arthropathic doses of bacterial cell walls demonstrate increased integrin mRNA expression and enhanced adhesion. To determine whether this augmented adhesion was causal in the development of synovial pathology, peptides synthesized from several fibronectin domains which inhibited leukocyte adhesion in vitro were administered to arthritic animals either as free peptides or coupled to a carrier molecule. Not only were peptides containing either the RGD or CS-1 cell-binding domains inhibitory to chronic synovial pathology (articular index = 10.5 +/- 0.3 for untreated animals compared to 1.25 +/- 0.25 for RGD and 2.5 +/- 0.7 for CS-1), but three peptides synthesized from the carboxy-terminal 33-kD heparin-binding domain of fibronectin were also found to significantly inhibit leukocyte recruitment and the evolution of arthritis. Based on these data, which are the first to explore the therapeutic potential of heparin-binding fibronectin peptides in chronic inflammation, it appears that antagonism of cellular adhesion and recruitment by fibronectin peptides may provide an important mechanism for modulating the multi-step adhesion process and attenuating aberrant inflammatory responses.

Calcium blocking agents may protect the ischaemic heart by reducing ventricular afterload and cardiac contractility, or by augmenting myocardial perfusion. To determine whether protection is mediated in part by mechanisms unrelated to myocardial work and perfusion, we examined effects of diltiazem and nitrendipine on unperfused myocardium subjected to hypoxia. Rabbit right ventricular papillary muscles were mounted in a myograph containing Krebs buffer equilibrated at 37 degrees C with 95% O2-5% CO2. During brief electrical pacing at a frequency of 12 min-1, a preload of 1363 +/- 60 mg produced a maximal isometric force development of 4892 +/- 273 mg (SE; n = 113). After 60 min without pacing, the quiescent muscles were pre-equilibrated randomly for 20 min without drug for control (C = 38), or with 10(-6) diltiazem (n = 38) or 10(-6) mol l-1 nitrendipine (n = 38). Changes in resting force during equilibration did not exceed +/- 12 mg. Subsequent sudden de-oxygenation with 95% N2-5% CO2 evoked in controls an increase in force beginning after 16 +/- 1 min. The onset of hypoxic contracture was significantly (P less than 0.1) delayed in treated muscles and started after 31 +/- 3 min with diltiazem and after 23 +/- 2 min with nifedipine. Peak contracture was significantly (P less than 0.1) inhibited by diltiazem and nitrendipine compared to controls, respectively values averaging 264 +/- 22 mg, 480 +/- 44 mg and 895 +/- 70 mg. Thus, calcium blockers delayed and suppressed hypoxic contracture in quiescent myocardium, demonstrating that the drugs acted directly on cardiac muscle in the absence of rhythmic electrical and mechanical activity.