Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Knowledge, attitudes, and behaviors related to the fentanyl-adulterated drug supply among people who use drugs in Oregon

INTRODUCTION

Nonpharmaceutical fentanyl has reconfigured the U.S. illicit drug market, contributing to a drastic increase in overdose drug deaths. While illicit fentanyl has subsumed the drug supply in the Northeast and Midwest, it has more recently reached the West. For this study, we explored knowledge, attitudes, and behaviors among people who use drugs in Oregon in the context of the emergence of fentanyl in the drug supply.

METHODS

We conducted in-depth interviews by phone with 34 people who use drugs in Oregon from May to June 2021. We used thematic analysis to analyze transcripts and construct themes.

RESULTS

People who use drugs knew about fentanyl, expressed doubt that fentanyl could be found in methamphetamine; believed those who were younger or less experienced were at higher risk for harm; and received information about fentanyl from drug dealers, syringe service programs, or peers (other people who use drugs). Preference for fentanyl's presence in drugs like heroin or methamphetamine was mixed. Some felt that their preference was irrelevant since fentanyl was unavoidable. Participants reported engaging in harm reduction practices, including communicating about fentanyl with dealers and peers, testing for fentanyl, using smaller quantities of drugs, switching from injecting to smoking, and using naloxone.

CONCLUSION

People who use drugs are responding to the rise of fentanyl on the West Coast and are concerned about the increasing uncertainty and hazards of the drug supply. They are willing and motivated to adopt harm reduction behaviors. Harm reduction promotion from syringe service programs and public health agencies is essential to reduce injury and death from nonpharmaceutical fentanyl.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Frailty and Constellations of Factors in Aging HIV-infected and Uninfected Women--The Women's Interagency HIV Study

BACKGROUND

Biological similarities are noted between aging and HIV infection. Middle-aged adults with HIV infection may present as elderly due to accelerated aging or having more severe aging phenotypes occurring at younger ages.

OBJECTIVES

We explored age-adjusted prevalence of frailty, a geriatric condition, among HIV+ and at risk HIV- women.

DESIGN

Cross-sectional.

SETTING

The Women's Interagency HIV Study (WIHS).

PARTICIPANTS

2028 middle-aged (average age 39 years) female participants (1449 HIV+; 579 HIV-).

MEASUREMENTS

The Fried Frailty Index (FFI), HIV status variables, and constellations of variables representing Demographic/health behaviors and Aging-related chronic diseases. Associations between the FFI and other variables were estimated, followed by stepwise regression models.

RESULTS

Overall frailty prevalence was 15.2% (HIV+, 17%; HIV-, 10%). A multivariable model suggested that HIV infection with CD4 count<200; age>40 years; current or former smoking; income ≤$12,000; moderate vs low fibrinogen-4 (FIB-4) levels; and moderate vs high estimated glomerular filtration rate (eGFR) were positively associated with frailty. Low or moderate drinking was protective.

CONCLUSIONS

Frailty is a multidimensional aging phenotype observed in mid-life among women with HIV infection. Prevalence of frailty in this sample of HIV-infected women exceeds that for usual elderly populations. This highlights the need for geriatricians and gerontologists to interact with younger 'at risk' populations, and assists in the formulation of best recommendations for frailty interventions to prevent early aging, excess morbidities and early death.

Improved Performance of High Areal Density Indirect Drive Implosions at the National Ignition Facility using a Four-Shock Adiabat Shaped Drive

Hydrodynamic instabilities can cause capsule defects and other perturbations to grow and degrade implosion performance in ignition experiments at the National Ignition Facility (NIF). Here, we show the first experimental demonstration that a strong unsupported first shock in indirect drive implosions at the NIF reduces ablation front instability growth leading to a 3 to 10 times higher yield with fuel ρR>1  g/cm(2). This work shows the importance of ablation front instability growth during the National Ignition Campaign and may provide a path to improved performance at the high compression necessary for ignition.

Population Genomics of the Euryhaline Teleost Poecilia latipinna

Global climate change and increases in sea levels will affect coastal marine communities. The conservation of these ecologically important areas will be a challenge because of their wide geographic distribution, ecological diversity and species richness. To address this problem, we need to better understand how the genetic variation of the species in these communities is distributed within local populations, among populations and between distant regions. In this study we apply genotyping by sequencing (GBS) and examine 955 SNPs to determine Sailfin molly (Poecilia latipinna) genetic diversity among three geographically close mangrove salt marsh flats in the Florida Keys compared to populations in southern and northern Florida. The questions we are asking are whether there is sufficient genetic variation among isolated estuarine fish within populations and whether there are significant divergences among populations. Additionally, we want to know if GBS approaches agree with previous studies using more traditional molecular approaches. We are able to identify large genetic diversity within each saltmarsh community (π ≈ 36%). Additionally, among the Florida Key populations and the mainland or between southern and northern Florida regions, there are significant differences in allele frequencies seen in population structure and evolutionary relationships among individuals. Surprisingly, even though the cumulative F_ST value using all 955 SNPs within the three Florida Key populations is small, there are 29 loci with significant F_ST values, and 11 of these were outliers suggestive of adaptive divergence. These data suggest that among the salt marsh flats surveyed here, there is significant genetic diversity within each population and small but significant differences among populations. Much of the genetic variation within and among populations found here with GBS is very similar to previous studies using allozymes and microsatellites. However, the meaningful difference between GBS and these previous measures of genetic diversity is the number of loci examined, which allows more precise delineations of population structure as well as facilitates identifying loci with excessive F_ST values that could indicate adaptive divergence.

First high-convergence cryogenic implosion in a near-vacuum hohlraum

Recent experiments on the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] demonstrate that utilizing a near-vacuum hohlraum (low pressure gas-filled) is a viable option for high convergence cryogenic deuterium-tritium (DT) layered capsule implosions. This is made possible by using a dense ablator (high-density carbon), which shortens the drive duration needed to achieve high convergence: a measured 40% higher hohlraum efficiency than typical gas-filled hohlraums, which requires less laser energy going into the hohlraum, and an observed better symmetry control than anticipated by standard hydrodynamics simulations. The first series of near-vacuum hohlraum experiments culminated in a 6.8 ns, 1.2 MJ laser pulse driving a 2-shock, high adiabat (α∼3.5) cryogenic DT layered high density carbon capsule. This resulted in one of the best performances so far on the NIF relative to laser energy, with a measured primary neutron yield of 1.8×10(15) neutrons, with 20% calculated alpha heating at convergence ∼27×.

Reduced instability growth with high-adiabat high-foot implosions at the National Ignition Facility

Hydrodynamic instabilities are a major obstacle in the quest to achieve ignition as they cause preexisting capsule defects to grow and ultimately quench the fusion burn in experiments at the National Ignition Facility. Unstable growth at the ablation front has been dramatically reduced in implosions with "high-foot" drives as measured using x-ray radiography of modulations at the most dangerous wavelengths (Legendre mode numbers of 30-90). These growth reductions have helped to improve the performance of layered DT implosions reported by O. A. Hurricane et al. [Nature (London) 506, 343 (2014)], when compared to previous "low-foot" experiments, demonstrating the value of stabilizing ablation-front growth and providing directions for future ignition designs.

Longitudinal health surveillance in a cohort of Gulf War veterans 18 years after first exposure to depleted uranium

As part of a longitudinal surveillance program, 35 members of a larger dynamic cohort of 79 Gulf War I veterans exposed to depleted uranium (DU) during combat underwent clinical evaluation at the Baltimore Veterans Administration Medical Center. Health outcomes and biomonitoring results were obtained to assess effects of DU exposure and determine the need for additional medical intervention. Clinical evaluation included medical and exposure histories, physical examination, and laboratory studies including biomarkers of uranium (U) exposure. Urine collections were obtained for U analysis and to measure renal function parameters. Other laboratory measures included basic hematology and chemistry parameters, blood and plasma U concentrations, and markers of bone metabolism. Urine U (uU) excretion remained above normal in participants with embedded DU fragments, with urine U concentrations ranging from 0.006 to 1.88 μg U/g creatinine. Biomarkers of renal effects showed no apparent evidence of renal functional changes or cellular toxicity related to U body burden. No marked differences in markers of bone formation or bone resorption were observed; however, a statistically significant decrease in levels of serum intact parathyroid hormone and significant increases in urinary calcium and sodium excretion were seen in the high versus the low uU groups. Eighteen years after first exposure, members of this cohort with DU fragments continue to excrete elevated concentrations of uU. No significant evidence of clinically important changes was observed in kidney or bone, the two principal target organs of U. Continued surveillance is prudent, however, due to the ongoing mobilization of uranium from fragment depots.

Surveillance results of depleted uranium-exposed Gulf War I veterans: sixteen years of follow-up

As part of a longitudinal surveillance program, 35 members of a larger cohort of 77 Gulf War I veterans who were victims of depleted uranium (DU) "friendly fire" during combat underwent a 3-day clinical assessment at the Baltimore Veterans Administration Medical Center (VAMC). The assessment included a detailed medical history, exposure history, physical examination, and laboratory studies. Spot and 24-h urine collections were obtained for renal function parameters and for urine uranium (U) measures. Blood U measures were also performed. Urine U excretion was significantly associated with DU retained shrapnel burden (8.821 mug U/g creatinine [creat.] vs. 0.005 mug U/g creat., p = .04). Blood as a U sampling matrix revealed satisfactory results for measures of total U with a high correlation with urine U results (r = .84) when urine U concentrations were >/=0.1 mug/g creatinine. However, isotopic results in blood detected DU in only half of the subcohort who had isotopic signatures for DU detectable in urine. After stratifying the cohort based on urine U concentration, the high-U group showed a trend toward higher concentrations of urine beta(2) microglobulin compared to the low-U group (81.7 v. 69.0 mug/g creat.; p = .11 respectively) and retinol binding protein (48.1 vs. 31.0 mug/g creat.; p = .07 respectively). Bone metabolism parameters showed only subtle differences between groups. Sixteen years after first exposure, this cohort continues to excrete elevated concentrations of urine U as a function of DU shrapnel burden. Although subtle trends emerge in renal proximal tubular function and bone formation, the cohort exhibits few clinically significant U-related health effects.

Health surveillance of Gulf War I veterans exposed to depleted uranium: updating the cohort

A cohort of seventy-four 1991 Gulf War soldiers with known exposure to depleted uranium (DU) resulting from their involvement in friendly-fire incidents with DU munitions is being followed by the Baltimore Veterans Affairs Medical Center. Biennial medical surveillance visits designed to identify uranium-related changes in health have been conducted since 1993. On-going systemic exposure to DU in veterans with embedded metal fragments is indicated by elevated urine uranium (U) excretion at concentrations up to 1,000-fold higher than that seen in the normal population. Health outcome results from the subcohort of this group of veterans attending the 2005 surveillance visit were examined based on two measures of U exposure. As in previous years, current U exposure is measured by determining urine U concentration at the time of their surveillance visit. A cumulative measure of U exposure was also calculated based on each veteran's past urine U concentrations since first exposure in 1991. Using either exposure metric, results continued to show no evidence of clinically significant DU-related health effects. Urine concentrations of retinol binding protein (RBP), a biomarker of renal proximal tubule function, were not significantly different between the low vs. high U groups based on either the current or cumulative exposure metric. Continued evidence of a weak genotoxic effect from the on-going DU exposure as measured at the HPRT (hypoxanthine-guanine phosphoribosyl transferase) locus and suggested by the fluorescent in-situ hybridization (FISH) results in peripheral blood recommends the need for continued surveillance of this population.

VEGF, PDGF alpha, PDGF beta, and C-Kit expression are not independent survival predictors in stage D2 prostate cancer (PC)

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Background: In PC, overexpression of VEGF, PDGF alpha, PDGF beta, and C-Kit has been reported in over 50% of biopsy samples and may be important predictors of survival. Methods: In an ongoing project, we reviewed the records of 26 patients (pts) with stage D2 PC and stained their archival tissue specimens for VEGF, PDGF alpha, PDGF beta, and C-Kit expression. Immunohistochemistry was performed at US LABS (Irvine CA). All immunostains were evaluated by two pathologists. Immunoreactivity was scored using a semiquantitative system for intensity of staining (0–3+) and % of tumor cells (0–3+). The total score was obtained by averaging the scores between the two readers. All pts had androgen deprivation and were followed at 3 months intervals with physical examination, CBC, chemistry profile and PSA levels. A stepwise Cox model was used with variables: Gleason score, Hemoglobin (Hgb), Alkaline Phosphatase (Alk Phos), PSA, LDH levels, and C-Kit positive or negative staining. Results: Median values were as follows: age 69 years (56–91), Alk Phos 139 U/L(60–1298), PSA 178 ng/ml (1.8–5677), LDH 169 IU/L (100–350), Hgb 12.8 gm/dl (6.8–16.3), Gleason score 8 (5–10), Survival 26 mos (8.3–144.1). The median value for C-Kit staining was 3 on a scale of 0–6. 18 pts were grouped into low staining group (0–4) and 8 pts in a high staining group (4.5–5). The Kappa Coefficient for C-Kit was 0.83, and ranged from 0.78–0.91 for the other 3 stains. In univariate survival analyses, C-Kit staining was a predictor for survival (p=0.037) but not PDGF alfa, PDGF beta, or VEGF. In the stepwise Cox model, independent survival predictors in order of significance were the Gleason score, Hgb, and PSA levels. Conclusions: In this sample, VEGF, PDGF alpha, PDGF beta, and C-Kit overexpression by immunohistochemistry in archival tissue are not independent predictors of survival. The C-Kit, however, has a small association with survival but may have collinearity with known predictors of survival.

No significant financial relationships to disclose.

Prenatal HgCl2 exposure in BALB/c mice: gender-specific effects on the ontogeny of the immune system

Because mercury is highly toxic to developing organisms, we tested the hypothesis that prenatal exposure to HgCl(2) can induce persistent immune dysfunction. Pregnant BALB/c mice were administrated every other day, for 11 days with HgCl(2) (200 microg/kg). Their offspring were studied at PND10, 14, 21, and 60. Lymph nodes (LN), spleens, and thymus were harvested and proliferation and cytokine production were studied in vitro. We report that prenatal HgCl(2) exposure exerts organ-specific effects on cell number, proliferation, and cytokine production in pre-weaning pups. At adulthood (PND60), effects of prenatal HgCl(2) exposure were still observed, but expressed differently in females and males. In adult females, an inhibitory effect was observed on cytokine production by thymocytes, LN cells, and splenocytes. In males, a stimulatory effect was observed. Overall, we conclude that in vivo exposures to low doses of HgCl(2) can induce persistent sex-specific immunotoxic effects, observable in adulthood.

Surveillance of depleted uranium exposed Gulf War veterans: health effects observed in an enlarged "friendly fire" cohort

To determine clinical health effects in a small group of US Gulf War veterans (n = 50) who were victims of depleted uranium (DU) "friendly fire," we performed periodic medical surveillance examinations. We obtained urine uranium determinations, clinical laboratory values, reproductive health measures, neurocognitive assessments, and genotoxicity measures. DU-exposed Gulf War veterans with retained metal shrapnel fragments were excreting elevated levels of urine uranium 8 years after their first exposure (range, 0.018 to 39.1 micrograms/g creatinine for DU-exposed Gulf War veterans with retained fragments vs 0.002 to 0.231 microgram/g creatinine in DU exposed but without fragments). The persistence of the elevated urine uranium suggests ongoing mobilization from the DU fragments and results in chronic systemic exposure. Clinical laboratory outcomes, including renal functioning, were essentially normal. Neurocognitive measures showing subtle differences between high and low uranium exposure groups, seen previously, have since diminished. Sister chromatid exchange frequency, a measure of mutation in peripheral lymphocytes, was related to urine uranium level (6.35 sister chromatid exchanges/cell in the high uranium exposure group vs 5.52 sister chromatid exchanges/cell in the low uranium exposure group; P = 0.03). Observed health effects were related to subtle but biologically plausible perturbations in central nervous system function and a general measure of mutagen exposure. The findings related to uranium's chemical rather than radiologic toxicity. Observations in this group of veterans prompt speculation about the health effects of DU in other exposure scenarios.

Factors associated with prevalent hepatitis C: differences among young adult injection drug users in lower and upper Manhattan, New York City

OBJECTIVES

This study examined correlates of prevalent hepatitis C virus (HCV) infection among young adult injection drug users in 2 neighborhoods in New York City.

METHODS

Injection drug users aged 18 to 29 years were street recruited from the Lower East Side and Harlem. Participants were interviewed about drug use and sex practices; venipuncture was performed for hepatitis B virus (HBV), HCV, and HIV serologies.

RESULTS

In both sites, testing positive for HCV antibody (anti-HCV) was associated with having injected for more than 3 years. Additionally, HCV infection was positively associated with injecting with someone known to have had hepatitis (but the association was significant only in the Lower East Side) and with sharing cotton (but the association was statistically significant only in Harlem). Being in drug treatment and older than 24 years were associated with HCV in the Lower East Side but not in Harlem. Receiving money for sex was associated with anti-HCV positivity in Harlem but not in the Lower East Side.

CONCLUSIONS

Several differences in factors associated with prevalent HCV infection existed among 2 populations of young injection drug users from the same city. Indirect transmission of HCV may occur.

Plasma and breast milk vitamin A as indicators of vitamin A status in pregnant women

Breast milk vitamin A is not well characterized as an indicator of vitamin A status in women with infections. A controlled trial of vitamin A, 3 mg retinol equivalent/day, was conducted among 697 pregnant women with human immunodeficiency virus (HIV) infection in Malawi which allowed comparison of plasma versus breast milk vitamin A as indicators of vitamin A status. Retinol concentrations were measured in plasma at baseline (18-28 weeks) and 38 weeks gestation and breast milk at 6 weeks post-partum. Plasma alpha 1-acid glycoprotein (AGP) and C-reactive protein (CRP) were measured at baseline. Plasma retinol (geometric mean, SD) at 38 weeks was 0.72 (0.44, 1.18) and 0.61 (0.38, 0.98) mumol/L (P < 0.0002) and breast milk retinol was 1.32 (0.71, 2.43) and 0.95 (0.49, 1.82) mumol/L (P < 0.0001) in vitamin A and placebo groups, respectively. Women with elevated acute phase protein (AGP > 1 gm/L and/or CRP > 5 mg/L) at baseline who received vitamin A had significantly higher plasma and breast milk vitamin A at follow-up compared with placebo. Elevated acute phase proteins did not distinguish women with low body stores of vitamin A. Breast milk retinol appears to be a better indicator of vitamin A status than plasma retinol in women with infections.

Lead effects on protamine-DNA binding

BACKGROUND

Lead impairs male fertility and may affect offspring of exposed males, but the mechanisms for this impairment are not completely clear. Protamine P1 and P2 families pack and protect mammalian sperm DNA. Human HP2 is a zinc-protein and may have an important role in fertility. As lead has affinity for zinc-containing proteins, we evaluated its ability in vitro to bind to HP2 and its effects on HP2-DNA binding. Methods and Results UV/VIS spectroscopic data indicated that HP2 binds both Pb(2+) and Zn(2+)(as chloride salts). They also provided evidence that thiol groups mainly participate for Zn(2+)-binding; however, HP2 has additional binding sites for Pb(2+). The mobility shift assay showed that lead interaction with HP2 caused a dose-dependent decrease on HP2 binding to DNA, suggesting that lead may alter chromatin stability.

CONCLUSIONS

These in vitro results demonstrate that lead can interact with HP2 altering the DNA-protamine binding. This chemical interaction of lead with protamines may result in chromatin alterations, which in turn may lead to male fertility problems and eventually to DNA damage.

Tietz syndrome (hypopigmentation/deafness) caused by mutation of MITF

Patients with Tietz syndrome have congenital profound deafness and generalised hypopigmentation, inherited in a fully penetrant autosomal dominant fashion. The pigmentary features and complete penetrance make this syndrome distinct among syndromes with pigmentary anomalies and deafness, which characteristically have patchy depigmentation and variable penetrance. Only one family has been reported with the exact features described in the original report of this syndrome. This family was reascertained and a missense mutation was found in the basic region of the MITF gene in family members with Tietz syndrome. Mutations in other regions of this gene have been found to produce Waardenburg syndrome type 2 (WS2), which also includes pigmentary changes and hearing loss, but in contrast to Tietz syndrome, depigmentation is patchy and hearing loss is variable in WS2.

Health effects of depleted uranium on exposed Gulf War veterans

A small group of Gulf War veterans possess retained fragments of depleted uranium (DU) shrapnel, the long-term health consequences of which are undetermined. We evaluated the clinical health effects of DU exposure in Gulf War veterans compared with nonexposed Gulf War veterans. History and follow-up medical examination were performed on 29 exposed veterans and 38 nonexposed veterans. Outcome measures employed were urinary uranium determinations, clinical laboratory values, and psychiatric and neurocognitive assessment. DU-exposed Gulf War veterans with retained metal shrapnel fragments are excreting elevated levels of urinary uranium 7 years after first exposure (range 0.01-30.7 microg/g creatinine vs 0.01- 0.05 microg/g creatinine in the nonexposed). The persistence of the elevated urine uranium suggests on-going mobilization from a storage depot which results in a chronic systemic exposure. Adverse effects in the kidney, a presumed target organ, are not present at this time, though other effects are observed. Neurocognitive examinations demonstrated a statistical relationship between urine uranium levels and lowered performance on computerized tests assessing performance efficiency. Elevated urinary uranium was statistically related to a high prolactin level (>1.6 ng/ml; P=0.04). More than 7 years after first exposure, DU-exposed Gulf War veterans with retained metal fragments continue to excrete elevated concentrations of urinary uranium. Effects related to this are subtle perturbations in the reproductive and central nervous systems.

Drug network characteristics as a predictor of cessation of drug use among adult injection drug users: a prospective study

Few studies have examined recovery from opiate and cocaine dependence without treatment, referred to as "natural recovery," "spontaneous recovery," and "spontaneous remission." The present study examined the relationship between network characteristics and cessation of heroin, cocaine, and crack use in a sample of underclass inner-city injection drug users in Baltimore, Maryland. Participants were enrolled in an experimental human immunodeficiency virus (HIV) preventive intervention. Between the baseline and follow-up interviews, which averaged 5.2 months, 24 (7%) of 335 participants reported ceasing to use heroin, cocaine, and crack. Individuals who had reported cessation of drug use at follow-up had reported at baseline a smaller proportion of their network members with whom they used drugs (p < .02). Using multiple logistic regression analyses and adjusting for baseline drug use, enrollment in drug treatment, and demographic and background variables, cessation of drug use was associated with a lower proportion of personal network members in one's drug network (odds ratio [OR] = 25.4, p < .05). The data from this study suggest that network members have potential for social influence on the cessation of drug use.

Genetic characterization of a Tn5-disrupted glycosyltransferase gene homolog in Brucella abortus and its effect on lipopolysaccharide composition and virulence

We constructed a rough mutant of Brucella abortus 2308 by transposon (Tn5) mutagenesis. Neither whole cells nor extracted lipopolysaccharide (LPS) from this mutant, designated RA1, reacted with a Brucella O-side-chain-specific monoclonal antibody (MAb), Bru-38, indicating the absence of O-side-chain synthesis. Compositional analyses of LPS from strain RA1 showed reduced levels of quinovosamine and mannose relative to the levels in the parental, wild-type strain, 2308. We isolated DNA flanking the Tn5 insertion in strain RA1 by cloning a 25-kb XbaI genomic fragment into pGEM-3Z to create plasmid pJM6. Allelic exchange of genomic DNA in B. abortus 2308 mediated by electroporation of pJM6 produced kanamycin-resistant clones that were not reactive with MAb Bru-38. Southern blot analysis of genomic DNA from these rough clones revealed Tn5 in a 25-kb XbaI genomic fragment. A homology search with the deduced amino acid sequence of the open reading frame disrupted by Tn5 revealed limited homology with various glycosyltransferases. This B. abortus gene has been named wboA. Transformation of strain RA1 with a broad-host-range plasmid bearing the wild-type B. abortus wboA gene resulted in the restoration of O-side-chain synthesis and the smooth phenotype. B. abortus RA1 was attenuated for survival in mice. However, strain RA1 persisted in mice spleens for a longer time than the B. abortus vaccine strain RB51, but as expected, neither strain induced antibodies specific for the O side chain.

Total chemical synthesis and high-resolution crystal structure of the potent anti-HIV protein AOP-RANTES

BACKGROUND

RANTES is a CC-type chemokine protein that acts as a chemoattractant for several kinds of leukocytes, playing an important pro-inflammatory role. Entry of human immunodeficiency virus-1 (HIV-1) into cells depends on the chemokine receptor CCR5. RANTES binds CCR5 and inhibits HIV-1 entry into peripheral blood cells. Interaction with chemokine receptors involves a distinct set of residues at the amino terminus of RANTES. This finding was utilized in the development of a chemically modified aminooxypentane derivative of RANTES, AOP-RANTES, that was originally produced from the recombinant protein using semisynthetic methods.

RESULTS

AOP-RANTES has been produced by a novel total chemical synthesis that provides efficient, direct access to large amounts of this anti-HIV protein analog. The crystal structure of chemically synthesized AOP-RANTES has been solved and refined at 1.6 A resolution. The protein is a dimer, with the amino-terminal pentane oxime moiety clearly defined.

CONCLUSIONS

Total chemical synthesis of AOP-RANTES provides a convenient method of producing the multi-milligram quantities of this protein needed to investigate the molecular basis of receptor binding and antiviral activity. This work provides the first truly high-resolution structure of a RANTES protein, although the structure of RANTES was known from previous nuclear magnetic resonance (NMR) determinations.

Family history of alcoholism and hypothalamic opioidergic activity

BACKGROUND

This study was designed to assess whether nonalcoholic offspring from families with a high density of alcohol-dependent individuals have altered endogenous central nervous system opioid activity. Naloxone hydrochloride stimulates plasma cortisol by blocking opioidergic input on the corticotropin-releasing factor neuron, thereby providing a noninvasive method for measuring hypothalamic opioid tone.

METHODS

Forty-eight nonalcoholic subjects aged 18 to 25 years were enrolled in a protocol to measure endogenous opioid activity by inducing opioid receptor blockade with the receptor antagonist, naloxone. Twenty-six subjects were offspring from families with a high density of alcohol dependence and were designated as family history-positive subjects. Twenty-two subjects were biological offspring of nonalcohol-dependent parents and designated as family history-negative subjects. Subjects received naloxone hydrochloride (0, 125, and 375 microg/kg) in double-blind, randomized order. Serum cortisol levels were monitored.

RESULTS

Family history-negative subjects had a graded cortisol response to each dose of naloxone. In contrast, family history-positive subjects achieved a maximal cortisol response to the 125-microg/kg dose of naloxone hydrochloride with no further increase in cortisol levels observed following the 375-microg/kg dose. Family history-negative subjects had a diminished cortisol response to the 125-microg/kg dose compared with the family history-positive subjects. Plasma naloxone concentrations did not differ between family history groups.

CONCLUSIONS

Individuals from families with a high density of alcohol dependence are more sensitive to naloxone compared with offspring of nonalcohol-dependent parents. This implies that individuals with a family history of alcohol dependence have diminished endogenous hypothalamic opioid activity.