Adaptations to water stress and pastoralism in the Turkana of northwest Kenya.

The Turkana people inhabit arid regions of east Africa-where temperatures are high and water is scarce-and they practice subsistence pastoralism, such that their diet is primarily composed of animal products. Working with Turkana communities, we sequenced 367 genomes and identified 8 regions putatively involved in adaptation to water stress and pastoralism. One of these regions includes a putative enhancer for STC1-a kidney-expressed gene involved in the response to dehydration and the metabolism of purine-rich foods such as red meat. We show that STC1 is induced by antidiuretic hormone in humans, is associated with urea levels in the Turkana themselves, and is under strong selection in this population (s∼0.041). This work highlights that partnerships with subsistence-level groups can lead to new models of human physiology with biomedical relevance.

Myocardial gene delivery using molecular cardiac surgery with recombinant adeno-associated virus vectors in vivo.

We use a novel technique that allows for closed recirculation of vector genomes in the cardiac circulation using cardiopulmonary bypass, referred to here as molecular cardiac surgery with recirculating delivery (MCARD). We demonstrate that this platform technology is highly efficient in isolating the heart from the systemic circulation in vivo. Using MCARD, we compare the relative efficacy of single-stranded (ss) adeno-associated virus (AAV)6, ssAAV9 and self-complimentary (sc)AAV6-encoding enhanced green fluorescent protein, driven by the constitutive cytomegalovirus promoter to transduce the ovine myocardium in situ. MCARD allows for the unprecedented delivery of up to 48 green fluorescent protein genome copies per cell globally in the sheep left ventricular (LV) myocardium. We demonstrate that scAAV6-mediated MCARD delivery results in global, cardiac-specific LV gene expression in the ovine heart and provides for considerably more robust and cardiac-specific gene delivery than other available delivery techniques such as intramuscular injection or intracoronary injection; thus, representing a potential, clinically translatable platform for heart failure gene therapy.

Cyclic-di-GMP-mediated repression of swarming motility by Pseudomonas aeruginosa: the pilY1 gene and its impact on surface-associated behaviors.

The intracellular signaling molecule cyclic-di-GMP (c-di-GMP) has been shown to influence surface-associated behaviors of Pseudomonas aeruginosa, including biofilm formation and swarming motility. Previously, we reported a role for the bifA gene in the inverse regulation of biofilm formation and swarming motility. The bifA gene encodes a c-di-GMP-degrading phosphodiesterase (PDE), and the Delta bifA mutant exhibits increased cellular pools of c-di-GMP, forms hyperbiofilms, and is unable to swarm. In this study, we isolated suppressors of the Delta bifA swarming defect. Strains with mutations in the pilY1 gene, but not in the pilin subunit pilA gene, show robust suppression of the swarming defect of the Delta bifA mutant, as well as its hyperbiofilm phenotype. Despite the ability of the pilY1 mutation to suppress all the c-di-GMP-related phenotypes, the global pools of c-di-GMP are not detectably altered in the Delta bifA Delta pilY1 mutant relative to the Delta bifA single mutant. We also show that enhanced expression of the pilY1 gene inhibits swarming motility, and we identify residues in the putative VWA domain of PilY1 that are important for this phenotype. Furthermore, swarming repression by PilY1 specifically requires the diguanylate cyclase (DGC) SadC, and epistasis analysis indicates that PilY1 functions upstream of SadC. Our data indicate that PilY1 participates in multiple surface behaviors of P. aeruginosa, and we propose that PilY1 may act via regulation of SadC DGC activity but independently of altering global c-di-GMP levels.

Kinetics and extent of T cell activation as measured with the calcium signal.

We have characterized the calcium response of a peptide-major histocompatibility complex (MHC)-specific CD4(+) T lymphocyte line at the single cell level using a variety of ligands, alone and in combination. We are able to distinguish four general patterns of intracellular calcium elevation, with only the most robust correlating with T cell proliferation. Whereas all three antagonist peptides tested reduce the calcium response to an agonist ligand, two give very different calcium release patterns and the third gives none at all, arguing that (a) antagonism does not require calcium release and (b) it involves interactions that are more T cell receptor proximal. We have also measured the time between the first T cell-antigen-presenting cell contact and the onset of the calcium signal. The duration of this delay correlates with the strength of the stimulus, with stronger stimuli giving a more rapid response. The dose dependence of this delay suggests that the rate-limiting step in triggering the calcium response is not the clustering of peptide-MHC complexes on the cell surface but more likely involves the accumulation of some intracellular molecule or complex with a half-life of a few minutes.

Early biochemical signals arise from low affinity TCR-ligand reactions at the cell-cell interface.

The kinetics of acid release by a mixture of T cells and antigen presenting cells were measured with a microphysiometer during a brief exposure to antigenic peptides. We find that some of the early biochemical events that lead to cellular proliferation cause a specific increase in the rate of acid release. The duration of this increase in acid release reflects the life-time of the peptide-MHC complexes. Peptides that form long-lived complexes produce a response that is stable for more than an hour. Serial TCR engagement is suggested by the observation that the amplitude of this stable response can be rapidly shifted up or down with additional agonist peptide or with antibodies that block T cell receptor binding. Cells briefly exposed to a peptide that forms short-lived peptide-MHC complexes produce a response that decays rapidly as peptide is washed away. A quantitative analysis of the kinetics of this decay in acidification demonstrates that intercellular TCR-ligand reactions are rapid, reversible, and of low apparent affinity with < 20% of peptide-MHC ligand bound to a TCR at any one time. These results demonstrate that the fraction of peptide-MHC ligands bound to TCRs at the cell-cell interface is no higher than anticipated from the affinities observed in solution for isolated TCRs and ligands.

Evidence that the autoimmune antigen myelin basic protein (MBP) Ac1-9 binds towards one end of the major histocompatibility complex (MHC) cleft.

The NH2-terminal peptide of myelin basic protein (MBP) bound to the class II major histocompatibility complex (MHC) protein I-Au is an immunodominant epitope in experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis. However, the MBP-I-Au complex is very unstable. To investigate this, we performed site-directed mutagenesis of the I-Au MHC protein and the MBP peptide. Biochemical, T cell activation, and molecular modeling studies of mutant complexes demonstrate that the MBP peptide's key residue for MHC binding, lysine 4, is buried in the P6 pocket of I-Au, which is predominantly hydrophobic. This implies that the MBP-I-Au complex differs from more stable complexes in two respects: (a) the peptide leaves the NH2-terminal region of the MHC peptide-binding cleft unoccupied; (b) the peptide is not anchored by typical favorable interactions between peptide side chains and MHC pockets. To test these hypotheses, a modified MBP peptide was designed based on molecular modeling, with the aim of producing strong I-Au binding. Extension of the NH2 terminus of MBP with six amino acids from the ova peptide, and replacement of the lysine side chain in the P6 pocket with an aromatic anchor, results in >1,000-fold increased binding stability. These results provide an explanation for the unusual peptide-MHC-binding kinetics of MBP, and should facilitate an understanding of why mice are not tolerant to this self-peptide- MHC complex.

Pathways to functional outcomes in schizophrenia: the role of premorbid functioning, negative symptoms and intelligence.

BACKGROUND: Social and intellectual premorbid functioning are generally estimated retrospectively, and related to clinical or hospitalization outcomes in schizophrenia. Yet the relationship between premorbid functioning assessed prior to psychiatric hospitalization and postmorbid functional outcomes has not been examined. OBJECTIVES: To test competing models of the relationship between (a) functional outcomes with (b) premorbid functioning assessed on nationally administered tests prior to psychiatric hospitalization, postmorbid intellectual functioning and symptomatology using a historical prospective design. METHODS: Ninety one inpatient and outpatient males with schizophrenia or schizoaffective disorder, aged 19 to 35, were examined using the Positive and Negative Syndrome Scale, the WAIS-III and Strauss and Carpenter social and occupational functional outcome scale. Premorbid intelligence and social functioning data were obtained from national standardized tests administered during high school prior to first hospitalization for schizophrenia. RESULTS: Path modeling showed that premorbid intelligence and behavioral functioning directly predicted postmorbid IQ and negative symptoms, and indirectly predicted postmorbid social and occupational functioning via negative symptoms. Item level analysis indicated that better social and occupational outcomes occurred in a group with few negative symptoms. CONCLUSIONS: Premorbid functioning, postmorbid IQ and negative symptoms are related, yet the relationship between premorbid functioning and postmorbid functional outcomes appears to be mediated by postmorbid negative symptoms.

Thyroxine: convesion to triiodothyronine by isolated perfused rat heart.

Thyroxine labeled with carbon-14 and iodine-125 was perfused through surviving rat hearts. Only when unlabeled triiodothyronine was added as a carrier could the newly formed doubly labeled triiodothyronine be isolated. The fact that this triiodothyronine was labeled with the correct ratio of carbon-14 to iodine-125 indicated that it originated from thyroxine. Approximately 5 percent of the initial carbon-14 radioactivity was found in the recovered triiodothyronine.

Validity of the premorbid adjustment scale.

BACKGROUND: The aim of the current study was to test the predictive and concurrent validity of the Premorbid Adjustment Scale (PAS) by comparing it with another similar but more elaborate retrospective measure and with data collected during late adolescence. METHODS: We compared PAS late adolescence scores (age 16-18 years) of 91 males with schizophrenia or schizoaffective disorder with data on behavior collected in adolescence, before the first psychotic episode as part of standardized Draft Board screening, and with the same measure readministered during adulthood and modified to collect the same data again retrospectively. RESULTS: The correlation of the PAS social withdrawal and social relations items with the social behavior scale of the Draft Board were .76 and .80, respectively, for the concurrent ratings and .52 and .53, respectively, for the data collected at age 17 years. The correlation of the PAS school achievements and school adjustment items with the functioning in structured environments scale of the Draft Board were .71 and .72, respectively, for the concurrent ratings and .43 and .47, respectively, for the data collected at age 17 years. CONCLUSIONS: Our results support the predictive and concurrent validity of the PAS and the validity of self-reported data on premorbid functioning in persons with schizophrenia.

Accuracy of self-reported premorbid functioning in schizophrenia.

BACKGROUND: Information on premorbid functioning is often based on patients recalling their past. Premorbid functioning is relevant as it is associated with treatment response and other outcomes. The extent to which memory impairments of persons with schizophrenia may bias such reporting has not been investigated. The purpose of the current study was to assess the extent to which persons with schizophrenia might exhibit biased reporting relative to controls. METHODS: Seventy males with schizophrenia or schizoaffective disorder and 51 males with no psychiatric symptoms participated in the study. Contemporaneous and retrospective reports from a behavioral functioning assessment conducted as part of the Israeli Draft Board were compared. This assessment routinely administered to all 17 years old males in the country assesses social functioning, individual autonomy, organizational ability, physical activity and functioning in structured environments. We compared the groups on the Draft Board behavioral measures at age 17 and at re-assessment. We also examined the relationship between symptom severity, neuropsychological performance and differences between age 17 and current behavioral assessment scores. RESULTS: In a repeated measures MANCOVA of the five measures there was no overall significant difference in accuracy of reporting between persons with schizophrenia and those without. Both groups showed a slight tendency to glorify their past. Consistency of reporting was not significantly correlated with neuropsychological performance or levels of psychotic symptoms. CONCLUSIONS: We found that when reporting on personal and social functioning during teen age years persons with schizophrenia report with the same level of consistency as persons without schizophrenia. This suggests that self-report of premorbid functioning of persons with schizophrenia can be trusted as being reasonably accurate.

Adenomas induced by polycyclic aromatic hydrocarbons in strain A/J mouse lung correlate with time-integrated DNA adduct levels.

The induction of DNA adducts and adenomas in the lungs of strain A/J mice has been investigated following the single i.p. administration of each of the following polycyclic aromatic hydrocarbons (PAH): pyrene, dibenz[a,h]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, 5-methylchrysene, and cyclopenta[c,d]pyrene. DNA adducts were measured by 32P-postlabeling at times between 1 and 21 days following injection, while adenomas were counted at 240 days after treatment. Pyrene did not induce either DNA adducts or lung adenomas at any of the doses examined. Each of the remaining PAH induced both adenomas and DNA adducts in a dose-dependent manner, with dibenz[a,h]anthracene > 5-methylchrysene > cyclopenta[c,d]pyrene > benzo[a]pyrene > benzo[b]fluoranthene. DNA adducts reached maximal levels between 3 and 9 days after injection, followed by a gradual decrease. The time-integrated DNA adduct level (TIDAL) was calculated by numerically integrating the areas under the adduct persistence curves extrapolated to 240 days for each PAH at each dose level. This value represents the effective total molecular dose of PAH that was delivered to the lung DNA over the entire course of tumorigenesis. A strong correlation of lung adenoma induction with the TIDAL values was observed for each PAH. The slopes of the tumors versus TIDAL value relationships were essentially identical for 5-methylchrysene, cyclopenta[cd]pyrene, benzo[a]pyrene, and benzo[b]fluoranthene. The slope of this relationship for dibenz[a,h]anthracene was markedly greater. The essentially identical induction of adenomas as a function of TIDAL values for these PAH suggests that the formation and persistence of DNA adducts determines their carcinogenic potency.

Alterations of lipid composition in a dystrophic muscle cell line.

The composition of neutral lipids and phospholipids was determined in normal (Cb7) and dystrophic (DyA4) cell lines, derived from cloned satellite cells from control and dystrophic C57BL/6J/dydy mice. The results obtained showed that dystrophic cells contain a higher relative distribution of phospholipids than their normal counterparts. Moreover, the distribution of individual phospholipids differs between normal and dystrophic cells, with increased percentage of acidic phospholipids and reduced proportion of phosphatidylcholine in dystrophic cells. Cholesterol was increased but free fatty acids decreased in dystrophic cells. The possible pathogenetic significance and functional consequences of these abnormalities are discussed.

Clostridial apoferredoxin messenger ribonucleic acid. Assay and partial purification.

An assay for Clostridium pasteurianum apoferredoxin messenger ribonucleic acid (mRNA) was developed, based on the synthesis of the protein in vitro. Quantitation of apoferredoxin synthesis was accomplished by trypsinization of the cell-free incubation labeled with 3H- or 14C-labeled amino acids, separation of the products by SDS-urea polyacrylamide gel electrophoresis, and excising and counting the NCS-solubilized gel band corresponding to the unique 52-amino acid tryptic peptide derived from apoferredoxin. Its synthesis was shown to be RNA dependent, and was optimized with respect to several parameters of the in vitro protein-synthesizing system. The specificity of the assay was examined with RNA from Clostridium acidi urici, a related species the ferredoxin of which does not yield the 52-amino acid tryptic peptide, and by the use of [3H]leucine, which is not present in C. pasteurianum apoferredoxin. By these methods, the overestimation of apoferredoxin synthesis due to the comigration of fragments from other in vitro products with the legitimate apoferredoxin-derived peptide could be accounted for. The apoferredoxin mRNA was partially purified by the sequential zonal sucrose gradient centrifugation of total RNA followed by Sephadex G-200 chromatography of the enriched RNA, after which a fraction was obtained in which apoferredoxin mRNA was 20-fold enriched. The enriched RNA fraction can now be used for further purification of the apoferredoxin-coding sequences by cloning procedures.

Association between nonpsychotic psychiatric diagnoses in adolescent males and subsequent onset of schizophrenia.

BACKGROUND: Nonpsychotic psychiatric symptoms may occasionally herald the later development of schizophrenia. This study followed a population-based cohort of adolescents with nonpsychotic, non-major affective psychiatric disorders to ascertain future hospitalization for schizophrenia. METHODS: Results of the medical and mental health assessments on 124 24416- to 17-year-old males screened by the Israeli draft board were cross-linked with the National Psychiatric Hospitalization case registry, which contains data on all psychiatric hospitalizations in the country, during a 4- to 8-year-long follow-up through age 25 years. In the cohort, 9365 adolescents were assigned a nonpsychotic, non-major affective diagnosis by the draft board. RESULTS: After excluding 167 adolescents who were hospitalized before or up to 1 year after the draft board assessment, 1.03% of the adolescents assigned a nonpsychotic, non-major affective psychiatric diagnosis, compared with only 0.23% of the adolescents without any psychiatric diagnosis, were later hospitalized for schizophrenia. Of the patients with schizophrenia, 26.8%, compared with only 7.4% in the general population, had been assigned a nonpsychotic, non-major affective psychiatric diagnosis in adolescence (overall odds ratio [OR], 4.5; 95% confidence interval [CI], 3.6-5.6), ranging from OR, 21.5 (95% CI, 12.6-36.6) for schizophrenia spectrum personality disorders to OR, 3.6 (95% CI, 2.1-6.2) for neurosis. CONCLUSION: These results reflect the relatively common finding of impaired functioning in patients later hospitalized for schizophrenia and the relatively low power of these disorders in predicting schizophrenia.

Adeno-associated virus expression systems for gene transfer.

In contrast to other gene delivery systems, adeno-associated virus vectors show long term gene expression without immune response or toxicity. New production methods have increased vector titers and eliminated adenovirus contamination, thereby facilitating effective in vivo use. These advancements will expedite additional animal model studies providing validation for use of this vector in human clinical trials.

Clinical pharmacology of filgrastim following high-dose chemotherapy and autologous bone marrow transplantation.

We evaluated the pharmacokinetics and pharmacodynamics of filgrastim during a Phase I study of this cytokine following high-dose chemotherapy and autologous bone marrow transplantation. Serum granulocyte colony-stimulating factor concentrations were determined by ELISA in 21 patients receiving 14-day continuous i.v. filgrastim infusions and 10 patients receiving daily 4-h infusions. Models were developed for filgrastim systemic clearance (Cls) by incorporation of receptor-binding theory. Mean plasma half-life (t1/2) in the 4-h infusion group was 197 min, and the volume of distribution approximated plasma volume. WBC counts transiently fell, then rebounded immediately postinfusion, which correlated with a delay in the disappearance of serum granulocyte colony-stimulating factor. The effect of WBC concentrations on filgrastim Cls was determined in patients receiving continuous infusions by segregation of study periods based on the presence of severe neutropenia. Clearance increased in all 14 patients receiving doses of 4-32 microgram/kg/day during WBC recovery. The effect of WBCs on Cls was described by a differential equation that included a static component and one component that varied with WBC concentration. These data suggest that currently used filgrastim dosing strategies following autologous bone marrow transplantation may be suboptimal.

Elevated endogenous serum macrophage colony-stimulating factor in the early stage of fungemia following bone marrow transplantation.

Murine studies have reported elevated serum macrophage colony-stimulating factor (M-CSF) concentrations in animals inoculated with fungus; however, the human cytokine response to fungemia has not been described. Endogenous M-CSF serum concentrations were measured in 18 autologous bone marrow transplant patients with positive blood fungal cultures. Seventeen of the 18 patients received the same high-dose chemotherapy regimen with autologous hematopoietic support. M-CSF concentrations were determined in serum samples obtained 1 week before and within 2 days of the first positive blood culture. Serum M-CSF rose more than three-fold in a majority of patients at the time of positive culture in contrast to concentrations obtained in the previous week (medians 11.1 and 2.8 ng/mL, respectively; p = 0.001). Median values at the time of positive blood culture were also significantly higher than those obtained in a matched control group of patients without positive blood cultures (n = 18; median 2.60 ng/mL; p = 0.001). These data demonstrate that endogenous serum M-CSF is elevated in the early stages of human systemic fungal infection and thus may have important diagnostic and therapeutic implications.

Usefulness of interim analyses in portending study results in antipsychotic and antidepressant trials.

It is unknown whether interim analyses portend final study results. Fatigue, pressure to complete trials and recruitment differences may mitigate against this. We examined the similarity of efficacy results of the first and second half of recruited patients to complete trials and explore possible intervening variables. Using data from the NewMeds repository of patient level data from placebo-controlled randomized trials of antipsychotics (AP) (22 studies, n=7056) and antidepressants (AD) (39 studies, n=12,217) we compared treatment effect size (placebo vs. active treatment) of the first and second half of patients recruited in completed trials. We found that in AP studies median difference in treatment effect between cohorts was -0.03, indicating that overall first and second cohorts yielded similar results. In AD studies, median difference between cohorts was 0.04, indicating that overall the second cohort had slightly larger active-placebo-difference. Overall, on average there were minimal differences in effect size between the first and the second cohorts, and in 30 of 39 trials interim results were a good estimate of the results on the 2nd cohort. In AD trials first and second cohort results were more similar when the proportion of patients per study centre and recruitment time of the two cohorts was similar. Results suggest that interim analyses in AD and AP studies may reliably serve to estimate ultimate effects and, at least in AD trials, are more accurate when the same sites are used to a similar extent and recruitment time of the two consequent cohorts is similar.

A simple spectrophotometric assay for micromolar amounts of lanthanum in the presence of calcium and phosphate.

A sensitive spectrophotometric assay for micromolar amounts of lanthanum in the presence of calcium and phosphate (as hydroxyapatite) was developed utilizing the change in absorption (at 652 nm) when the dye arsenazo III was complexed with lanthanum. Arsenazo III was used at a level of 25 microM and the solution pH was maintained at 3.1 with 0.2 M sodium acetate. Lanthanum concentrations down to 0.5 microM could be reliably assayed. Calcium ion did not complex well with arsenazo III at pH 3.1. With calcium present at 100 microM and lanthanum at 10 microM, the assay was 115 times more sensitive for lanthanum. The assay is simple, rapid, reproducible and, unlike the assay using radioactive lanthanum, can be performed at any time.