Depression, anxiety and PTSD symptoms before and during the COVID-19 pandemic in the UK

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors.

METHOD

Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change.

RESULTS

Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status.

CONCLUSIONS

We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.

Neutralising antibodies in Spike mediated SARS-CoV-2 adaptation

SARS-CoV-2 Spike protein is critical for virus infection via engagement of ACE2, and amino acid variation in Spike is increasingly appreciated. Given both vaccines and therapeutics are designed around Wuhan-1 Spike, this raises the theoretical possibility of virus escape, particularly in immunocompromised individuals where prolonged viral replication occurs. Here we report chronic SARS-CoV-2 with reduced sensitivity to neutralising antibodies in an immune suppressed individual treated with convalescent plasma, generating whole genome ultradeep sequences by both short and long read technologies over 23 time points spanning 101 days. Although little change was observed in the overall viral population structure following two courses of remdesivir over the first 57 days, N501Y in Spike was transiently detected at day 55 and V157L in RdRp emerged. However, following convalescent plasma we observed large, dynamic virus population shifts, with the emergence of a dominant viral strain bearing D796H in S2 and ΔH69/ΔV70 in the S1 N-terminal domain NTD of the Spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype diminished in frequency, before returning during a final, unsuccessful course of convalescent plasma. In vitro, the Spike escape double mutant bearing ΔH69/ΔV70 and D796H conferred decreased sensitivity to convalescent plasma, whilst maintaining infectivity similar to wild type. D796H appeared to be the main contributor to decreased susceptibility, but incurred an infectivity defect. The ΔH69/ΔV70 single mutant had two-fold higher infectivity compared to wild type and appeared to compensate for the reduced infectivity of D796H. Consistent with the observed mutations being outside the RBD, monoclonal antibodies targeting the RBD were not impacted by either or both mutations, but a non RBD binding monoclonal antibody was less potent against ΔH69/ΔV70 and the double mutant. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy associated with emergence of viral variants with reduced susceptibility to neutralising antibodies.

In vitro self-assembly of human pericyte-supported endothelial microvessels in three-dimensional coculture: a simple model for interrogating endothelial-pericyte interactions

We describe a method for coculture of macro- or microvascular human endothelial cells (ECs) and pericytes (PCs) within a 3-dimensional (3-D) protein matrix resulting in lumenized EC cords invested by PCs. To prevent apoptotic cell death of ECs in 3-D culture, human umbilical vein or dermal microvascular ECs were transduced to express the antiapoptotic protein Bcl-2. To prevent PC-mediated gel contraction, the collagen-fibronectin gel was polymerized within a polyglycolic acid nonwoven matrix. Over the first 24-48 h, EC-only gels spontaneously formed cords that developed lumens via vacuolization; such vascular networks were maintained for up to 7 days. In EC-PC cocultures, PCs were recruited to the EC networks. PC investment of EC cords both limited the lumen diameter and increased the degree of vascular network arborization. Peg and socket junctions formed between ECs and PCs in this system, but dye transfer, indicative of gap junction formation, was not observed. This simple system can be used to analyze bidirectional signals between ECs and PCs in a 3-D geometry.

Extra-phosphoric effects of superdoses of a novel microbial phytase

An experiment was conducted to evaluate the influence of a novel microbial phytase on broiler performance from d 0 to 42 and tibia ash at d 21. Male Cobb 500 broilers (n = 2,016) were fed 1 of 7 experimental diets: positive control (PC) formulated to meet or exceed nutrient recommendations; PC plus dicalcium phosphate (PC+DCP) formulated to provide Ca and P at 0.10% above the PC; PC plus 500 U/kg of microbial phytase (PC+500); negative control (NC) with Ca and P reduced from the PC by 0.16 and 0.15%, respectively; and NC plus 500 (NC+500), 1,000 (NC+1,000), or 1,500 (NC+1,500) U/kg of microbial phytase. Diets were fed in 3 phases from d 0 to 21, d 22 to 42, and d 43 to 49 to 32 birds/pen and 9 replicate pens/diet. From d 0 to 21, broilers fed the NC diet had decreased (P ≤ 0.05) BW gain and tibia ash compared with broilers fed all other diets, except tibia ash in birds fed PC+500. Phytase supplementation at 500, 1,000, or 1,500 U/kg to the NC improved (P ≤ 0.05) BW gain and tibia ash comparable with the PC. Feed conversion ratio (FCR) was improved (P ≤ 0.05) in broilers fed NC+1,500 compared with broilers fed all other diets. From d 0 to 49, growth performance was not influenced (P > 0.05) by diet. However, FCR was improved (P ≤ 0.05) in broilers fed 1,500 U/kg of microbial phytase compared with broilers fed the PC, PC+DCP, and NC. There were no differences in performance or tibia ash between broilers fed the PC or PC+DCP, which would indicate the PC diet was sufficient in Ca and P. Therefore, the improvements in FCR in the NC+1500 may be associated with mitigation of the antinutrient effects of phytate rather than improved P utilization.

Relationship between external stink bug (Hemiptera: Pentatomidae) boll-feeding symptoms and internal boll damage with respect to cotton lint gin-out and fiber quality

Cotton, Gossypium hirsutum L., bolls from 17 field locations in northeastern North Carolina and southeastern Virginia, having 20% or greater internal boll damage, were studied to determine the relationship between external feeding symptoms and internal damage caused by stink bug (Hemiptera: Pentatomidae) feeding. In 2006 and 2007, two cohorts of 100 bolls each were sampled at all field locations. The first cohort was removed as bolls reached approximately quarter size in diameter (2.4 cm). External and internal symptoms of stink bug feeding were assessed and tabulated. Concurrent to when the first cohort was collected, a second cohort of quarter-size-diameter bolls was identified, tagged, examined in situ for external feeding symptoms (sunken lesions), and harvested at the black seed coat stage. Harvested bolls were assessed for internal damage and locks were categorized (undamaged, minor damage, or major damage), dried, and ginned. Lint samples from each damage category were submitted for high volume instrument and advanced fiber information system quality analyses. Significant, moderately strong Pearson correlation coefficients existed between number of external stink bug feeding lesions and internal damage. Pearson correlation of total external lesions with total internal damage was stronger than any correlation among the other single components compared. Predictability plots indicated a rapid increase in relationship strength when relating external stink bug lesions to internal damage as the number of external lesions increased. Approximately 90% predictability of internal damage was achieved with four (2006) or six (2007) external lesions per boll. Gin-turnout and fiber quality decreased with increasing intensity of internal stink bug damage.

TNF receptors differentially signal and are differentially expressed and regulated in the human heart

Tumor necrosis factor (TNF) utilizes two receptors, TNFR1 and 2, to initiate target cell responses. We assessed expression of TNF, TNFRs and downstream kinases in cardiac allografts, and compared TNF responses in heart organ cultures from wild-type ((WT)C57BL/6), TNFR1-knockout ((KO)), TNFR2(KO), TNFR1/2(KO) mice. In nonrejecting human heart TNFR1 was strongly expressed coincidentally with inactive apoptosis signal-regulating kinase-1 (ASK1) in cardiomyocytes (CM) and vascular endothelial cells (VEC). TNFR2 was expressed only in VEC. Low levels of TNF localized to microvessels. Rejecting cardiac allografts showed increased TNF in microvessels, diminished TNFR1, activation of ASK1, upregulated TNFR2 co-expressed with activated endothelial/epithelial tyrosine kinase (Etk), increased apoptosis and cell cycle entry in CM. Neither TNFR was expressed significantly by cardiac fibroblasts. In (WT)C57BL/6 myocardium, TNF activated both ASK1 and Etk, and increased both apoptosis and cell cycle entry. TNF-treated TNFR1(KO) myocardium showed little ASK1 activation and apoptosis but increased Etk activation and cell cycle entry, while TNFR2(KO) myocardium showed little Etk activation and cell cycle entry but increased ASK1 activation and apoptosis. These observations demonstrate independent regulation and differential functions of TNFRs in myocardium, consistent with TNFR1-mediated cell death and TNFR2-mediated repair.

Efficacy of transgenic cotton expressing Cry1Ac and Cry1F insecticidal protein against heliothines (Lepidoptera: Noctuidae)

Cotton, Cossypium hirsutum L, plants expressing Cry1Ac and Cry1F (Phytogen 440W) insecticidal crystal proteins of Bacillus thuringiensis (Bt) Berliner, were evaluated against natural populations of tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), across 13 southern U.S. locations that sustained low, moderate, and high infestations. The intrinsic activity of Phytogen 440W was compared with nontreated non-Bt cotton (PSC355) and with management strategies in which supplemental insecticides targeting heliothines were applied to Phytogen 440W and to PSC355 cotton. Infestations were composed primarily of bollworm, which is the least sensitive of the heliothine complex to Cry toxins. Therefore, damage recorded in these studies was primarily due to bollworm. Greater than 75% of all test sites sustained heliothine infestations categorized as moderate to high (10.6-64.0% peak damaged bolls in nontreated PSC355). Phytogen 440W, alone or managed with supplemental insecticide applications, reduced heliothine-damaged plant terminals, squares (flower buds), flowers, and bolls equal to or better (1.0-79.0-fold) than managing a non-Bt cotton variety with foliar insecticides across all infestation environments. Rarely (frequency of < or = 11% averaged across structures), sprayed Phytogen 440W reduced damaged structures compared with nontreated Phytogen 440W. Protection against heliothine-induced plant damage was similar across the three levels of infestation for each viable management strategy, with exception to damaged squares for nontreated Phytogen 440W. In situations of moderate to high heliothine infestations, cotton plants expressing Cry1Ac and Cry1F may sustain higher levels of damage compared with that same variety in low infestations. No significant difference in yield was observed among heliothine management strategies within each infestation level, indicating cotton plants may compensate for those levels of plant damage. These findings indicate Phytogen 440W containing Cry1Ac and Cry1F provided consistent control of heliothines across a range of environments and infestation levels.

TNF-mediated inflammatory disease

TNF was originally described as a circulating factor that can cause necrosis of tumours, but has since been identified as a key regulator of the inflammatory response. This review describes the known signalling pathways and cell biological effects of TNF, and our understanding of the role of TNF in human disease. TNF interacts with two different receptors, designated TNFR1 and TNFR2, which are differentially expressed on cells and tissues and initiate both distinct and overlapping signal transduction pathways. These diverse signalling cascades lead to a range of cellular responses, which include cell death, survival, differentiation, proliferation and migration. Vascular endothelial cells respond to TNF by undergoing a number of pro-inflammatory changes, which increase leukocyte adhesion, transendothelial migration and vascular leak and promote thrombosis. The central role of TNF in inflammation has been demonstrated by the ability of agents that block the action of TNF to treat a range of inflammatory conditions, including rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease and psoriasis. The increased incidence of infection in patients receiving anti-TNF treatment has highlighted the physiological role of TNF in infectious diseases.

Effects of vegetated field borders on arthropods in cotton fields in eastern North Carolina

The influence, if any, of 5m wide, feral, herbaceous field borders on pest and beneficial arthropods in commercial cotton, Gossypium hirsutum (L.) (Malvales: Malvaceae), fields was measured through a variety of sampling techniques over three years. In each year, 5 fields with managed, feral vegetation borders and five fields without such borders were examined. Sampling was stratified from the field border or edge in each field in an attempt to elucidate any edge effects that might have occurred. Early season thrips populations appeared to be unaffected by the presence of a border. Pitfall sampling disclosed no differences in ground-dwelling predaceous arthropods but did detect increased populations of crickets around fields with borders. Cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) populations were too low during the study to adequately assess border effects. Heliothines, Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), egg numbers and damage rates were largely unaffected by the presence or absence of a border, although in one instance egg numbers were significantly lower in fields with borders. Overall, foliage-dwelling predaceous arthropods were somewhat more abundant in fields with borders than in fields without borders. Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae) were significantly more abundant in fields with borders, but stink bugs, Acrosternum hilare (Say), and Euschistus servus (Say) (Hemiptera: Pentatomidae) numbers appeared to be largely unaffected by border treatment. Few taxa clearly exhibited distributional edge effects relative to the presence or absence of border vegetation. Field borders like those examined in this study likely will have little impact on insect pest management in cotton under current insect management regimens.

Effect of tobacco budworm (Lepidoptera: Noctuidae) infestation level on budworm-resistant and -susceptible varieties of flue-cured tobacco in North Carolina

Field experiments were conducted from 1972 to 1978 and from 1998 to 1999 to evaluate tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), larval feeding on flue-cured tobacco, Nicotiana tabacum (L.), yield in eastern North Carolina. In the earlier studies, using variety Coker 319, treatment plots were evaluated when either 0 or 100% of plants in a plot were infested with H. virescens larvae. Treatment differences based on actual yield loss (kilograms per hectare) were compared with estimations of yield loss based on leaf consumption and leaf loss. Results indicate actual yield loss when 100% of plants were infested was less than the corresponding estimates of yield loss. In the later experiments, two tobacco budworm-resistant lines, 'CU 263' and 'CU 370', were compared with a commercial susceptible variety, K 326, when 0, 10, 20, or 40% of plants were infested (1998) and 0, 10, 40, 75, or 100% of plants were infested (1999). Although significant increases in leaf equivalents consumed were associated with infestations exceeding the recommended threshold, differences were not detected for yield (kilograms per hectare), quality (dollars per kilogram), and value (dollars per hectare) within each tobacco line. Additionally, there was not a significant correlation between value and infestations level for any of the tobacco lines. These results provide economic support for tolerance of a higher treatment threshold. Although K 326 sustained more leaf equivalent loss than CU 263 and CU 370, the value of K 326 harvested was higher than that of CU 263 and CU 370. To justify use of resistant varieties, the combination of pest pressure and the benefit of host plant resistance must be greater than the capacity of a susceptible variety to produce competitive yields, despite sustaining significantly higher loss.

Cross-resistance responses of CrylAc-selected Heliothis virescens (Lepidoptera: Noctuidae) to the Bacillus thuringiensis protein vip3A

One susceptible and three Cry1Ac-resistant strains of tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used in laboratory studies to determine the level of cross-resistance between the Bacillus thuringiensis (Berliner) toxins Cry1Ac and Vip3A by using concentration-mortality and leaf tissue experiments. Concentration-mortality data demonstrated that the three Cry1Ac-resistant H. virescens strains, YHD2, KCBhyb, and CxC, were at least 215- to 316-fold resistant to Cry1Ac compared with the susceptible strain, YDK. Results from Vip3A concentration-mortality tests indicated that mortality was similar among all four H. virescens strains. Relative larval growth on Cry1Ac reflected concentration-mortality test results, because YHD2 larval growth was mostly unaffected by the Cry1Ac concentrations tested. Growth ratios for KCBhyb and CXC indicated that they had a more moderate level of resistance to Cry1Ac than did YHD2. Relative larval growth on Vip3A was highly variable at lower concentrations, but it was more consistent on concentrations of Vip3A above 25 microg/ml. Differences in larval growth among strains on Vip3A were not as pronounced as seen in Cry1Ac experiments. Mortality and larval growth also was assessed in leaf tissue bioassays in which YDK, CxC, and KCBhyb neonates were placed onto leaf disks from non-Bt and Bt cotton, Gossypium hirsutum L., for 5 d. Three Bt lines were used in an initial bioassay and consisted of two Vip3A-containing lines, COT203 and COT102, and a Cry1Ac-producing line. Mortality of KCBhyb and CXC was lower than that of YDK larvae in the presence of leaf tissue from the Cry1Ac-producing line. Additionally, increased larval growth and leaf tissue consumption on Cry1Ac-containing leaf disks was observed for KCBhyb and CXC. Mortality and larval weights were similar among strains when larvae were fed leaf tissue of either non-Bt, COT203, or COT102. A subsequent leaf tissue bioassay was conducted that evaluated four cotton lines: non-Bt, Cry1Ab-expressing, Vip3A-expressing, and pyramided-toxin plants that produced both Cry1Ab and Vip3A. Mortality levels were similar among strains when fed non-Bt, Vip3A-expressing, or pyramided-toxin leaf tissues. Mortality was higher for YDK than for KCBhyb or CXC on Cry1Ab-expressing leaf tissues. No differences in larval weights were observed among strains for any genotype tested. Results of these experiments demonstrate that cross-resistance is nonexistent between CrylAc and Vip3A in H. virescens. Thus, the introduction of Vip3A-producing lines could delay Cry1Ac-resistance evolution in H. virescens, if these lines gain a significant share of the market.

Genetic variation for resistance to Bacillus thuringiensis toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in eastern North Carolina

To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 microg/ml Cry1Ac toxin, or diet containing 5.0 microg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).

Comparative production of Helicoverpa zea (Lepidoptera: Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays

Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001-2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4-L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.

Estimated frequency of nonrecessive Bt resistance genes in bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in eastern North Carolina

In summer 2000, adult female bollworm moths, Helicoverpa zea (Boddie), were collected from light-traps at four locations near the Tidewater Research Station, Plymouth, NC. Female moths were allowed to lay eggs, and at hatch, 72 larvae from each female were screened for growth rate on normal artificial diet and on diets containing 5.0 microg of either Cry1Ac or Cry2Aa Bt toxin per milliliter of diet. The growth rate bioassays were performed to isolate nonrecessive Bt resistance genes present in field populations of bollworm. We found one individual out of 583 screened that appeared to carry a major gene for resistance to Cry1Ac. Assuming four alleles per individual, the gene frequency is 1/2332 or 0.0003. Other females appeared to have minor genes for Cry1Ac resistance or major genes with lower levels of dominance. We also found one individual out of 646 screened that appeared to carry a major gene for resistance to Cry2Aa. The gene frequency for Cry2Aa resistance was estimated at 1/2584 or 0.00039. Again, other females seemed to carry additional minor resistance genes. Along with other results that indicate partially dominant inheritance of Cry1Ac resistance in bollworm, these allele frequency estimates are important for determining the rate of resistance evolution in H. zea to specific Bt toxins.

Expression of tumor necrosis factor receptors in normal kidney and rejecting renal transplants

Activation of the TNF signal transduction cascade is initiated by the interaction of TNF with either of two cell surface receptors, TNFR-1 and TNFR-2. The levels and regulation of expression of these two receptors has been extensively analyzed in cultured cells, but little is known of TNFR expression in situ. We analyzed the expression of TNFR-1 and -2 in normal human renal kidney and in renal transplants undergoing acute cellular rejection. Immunohistochemistry and immunogold electron microscopy indicated a strong expression of TNFR-1 on the endothelium of glomeruli of normal kidney. Immunogold colocalization for TNFR-1 and a marker of the trans-Golgi network (TGN-46) demonstrated TNFR-1 within the Golgi complex in endothelial cells in normal kidney, confirming our previous studies with cultured cells. TNFR-1 expression was lost in glomeruli from acutely rejecting kidney, but TNFR-1 was detected in abundance on infiltrating leukocytes in the interstitium of allografts with acute rejection. In contrast, TNFR-2 was demonstrated predominantly in epithelial cells of distal convoluted tubule (DCT) in acute rejection kidney near TNF-expressing leukocytes. TNF was absent in normal kidney, but present in rejecting allograft. TNF was found in infiltrating leukocytes and in adjacent tubular epithelial cells. In situ hybridization showed TNFR-1 mRNA within the endothelium of the glomeruli and of a few arterioles in normal kidney, whereas TNFR-2 mRNA was seen in tubular epithelial cells of the DCT in acute transplant rejection. These data reveal that there is both differential expression and regulation of the two TNF receptors in human kidney.

Tumor necrosis factor receptor-associated factors (TRAFs)

Tumor necrosis factor receptor-associated factors (TRAFS) were initially discovered as adaptor proteins that couple the tumor necrosis factor receptor family to signaling pathways. More recently they have also been shown to be signal transducers of Toll/interleukin-1 family members. Six members of the TRAF family have been identified. All TRAF proteins share a C-terminal homology region termed the TRAF domain that is capable of binding to the cytoplasmic domain of receptors, and to other TRAF proteins. In addition, TRAFs 2-6 have RING and zinc finger motifs that are important for signaling downstream events. TRAF proteins are thought to be important regulators of cell death and cellular responses to stress, and TRAF2, TRAF5 and TRAF6 have been demonstrated to mediate activation of NF-kappaB and JNK. TRAF proteins are expressed in normal and diseased tissue in a regulated fashion, suggesting that they play an important role in physiological and pathological processes.

Physiological aspects of pig-to-primate renal xenotransplantation

BACKGROUND

Few data exist on the physiological aspects of pig-to-primate renal xenotransplantation.

METHODS

Use of organs transgenic for human decay accelerating factor has allowed assessment of the metabolic and hormonal functions of these xenografts.

RESULTS

Porcine renal xenografts largely maintain plasma electrolyte homeostasis. An increase in proteinuria was detected that may result from graft injury. In contrast to allotransplantation a severe anaemia developed requiring recipient treatment with exogenous human erythropoietin.

CONCLUSIONS

Our experience provides qualified encouragement for the likely physiological compatibility of pig and primate species, but identifies areas where a xenograft may not match the performance of an allograft.

Relationship between cereal leaf beetle (Coleoptera: Chrysomelidae) egg and fourth-instar populations and impact of fourth-instar defoliation of winter wheat yields in North Carolina and Virginia

Cereal leaf beetle, Oulema melanopus (L.), has become a serious pest of small grains in the mid-Atlantic region of the United States. Existing thresholds for implementing control measures allowed too much leaf damage and consequent yield loss to occur before recommending treatment. Information on beetle biology and crop response to injury, both prerequisites for developing new management strategies, was lacking for this region. A 3-yr project was initiated to generate an area wide cereal leaf beetle biological and yield impact database for winter wheat, and to evaluate the injury and yield loss potential of different population densities. Over the study period, beetle populations were evaluated at 26 winter wheat field locations in Virginia and North Carolina. Eggs and larvae, classified to instar, were counted twice each week from February to June. Replicated insecticide versus noninsecticide treatments were conducted at each location where leaf defoliation and yield were documented. Results showed that the relationship between 50th percentile egg and fourth-instar population estimates were in strong agreement (y = 0.36x - 0.01; r2 = 0.79). Potentially detrimental larval infestations were forecast before appearance of foliage injury from egg populations present during the stem elongation to flag leaf emergence developmental stages. A significant positive linear relationship between total fourth instar per stem population estimates and percent flag leaf defoliation was detected (y = 20.29x + 1.34; r2 = 0.60). A weaker but still significant relationship between the total fourth-instar population estimates and percent yield loss was found (y = 11.74x + 6.51; r2 = 0.26), indicating that factors in addition to flag leaf injury, primarily by fourth instars, also contributed to reduced yields.

Caveolin-1 associates with TRAF2 to form a complex that is recruited to tumor necrosis factor receptors

Tumor necrosis factor (TNF) receptor-associated factor (TRAF) 2 is an intracellular adapter protein, which, upon TNF stimulation, is directly recruited to the intracellular region of TNF receptor 2 (TNFR2) or indirectly, via TRADD, to the intracellular region of TNF receptor 1 (TNFR1). In cultured human umbilical vein endothelial cells, endogenous TRAF2 colocalizes with the membrane-organizing protein caveolin-1 at regions of enrichment subjacent to the plasma membrane as detected by confocal fluorescence microscopy. Both endogenous and transfected TRAF2 protein coimmunoprecipitate with caveolin-1 in the absence of ligand. Upon TNF treatment, the TRAF2-caveolin-1 complex transiently associates with TRADD, and upon overexpression of TNFR2, the TRAF2-caveolin-1 complex stably associates with and causes redistribution of this receptor as detected by confocal fluorescence microscopy. In human embryonic kidney 293 cells, which have minimal endogenous expression of caveolin-1, cotransfection of TRAF2 and caveolin-1 results in spontaneous association of these proteins which can further associate with and redistribute transfected TNFR2 molecules. The association of caveolin-1 with TNFR2 depends upon TRAF2. Cotransfection of caveolin-1 protein increases TRAF2 protein expression levels in HEK 293 cells, which correlates with enhancement of TNF and TRAF2 signaling, measured as transcription of a NF-kappaB promoter-reporter gene, although the caveolin-enhanced response to TNF is attenuated at higher caveolin levels. These findings suggest that intracellular distribution of activated TNF receptors may be regulated by caveolin-1 via its interaction with TRAF2.

Long-term survival of nonhuman primates receiving life-supporting transgenic porcine kidney xenografts

BACKGROUND

Recently, there has been a resumed interest in clinical xenotransplantation using pig organs. However, no data are available yet regarding the capacity of porcine organs to sustain the life of a primate beyond the first month. We have attempted to obtain long-term survival of nonhuman primates using human decay-accelerating factor (hDAF) transgenic pig organs and an immunosuppressive strategy particularly aimed at neutralizing the humoral component of the immune response.

METHODS

hDAF transgenic or control kidneys were transplanted into 14 bilaterally nephrectomized cynomolgus monkeys (Macaca fascicularis) that underwent splenectomy and were immunosuppressed with cyclosporine A, cyclophosphamide, and steroids. All animals also received recombinant erythropoietin. Postoperatively, the primates were monitored daily. Laboratory evaluations included serum biochemistry, hematology, and measurements of hemolytic antipig antibodies. To assess the role of splenectomy in the control of humoral response, historical data were also used from a group of monkeys (n=7) that received the same immunosuppressive regimen and an hDAF transgenic porcine kidney but did not have splenectomy or receive recombinant erythropoietin.

RESULTS

This immunosuppressive approach obtained the longest survival time (78 days) described to date of a primate receiving a life-supporting porcine renal xenograft. Furthermore, four of nine animals in this series survived for 50 days or more. Most biochemical measurements in this study (including plasma urea, creatinine, sodium, and potassium concentrations) remained within normal ranges for several weeks in all of the longest-surviving animals.

CONCLUSIONS

Normalization of renal function (urea and creatinine) in primate recipients of porcine renal xenografts suggests that pig kidneys may be suitable for future clinical xenotransplantation. Additional immunosuppressive approaches, specifically designed to prevent humorally mediated immunological damage, should be explored to further prolong survival of primates that have received porcine xenografts.

Growth of porcine kidneys in their native and xenograft environment

The increased survival of hDAF pig-to-primate renal xenografts for up to two months has afforded the opportunity to study physiological aspects such as organ growth. Experimental evidence exists of species restriction of the activity of growth hormone, although growth itself is also controlled by a number of other endocrine, paracrine and autocrine substances. This study consisted of four parts: (1) measurement of pig kidney size according to pig body weight; (2) measurement of pig kidney size according to pig age; (3) serial length measurement of pig-to-primate renal xenografts; (4) correlation of terminal weight of renal xenograft with age and histology. The xenografted pig kidneys in a primate recipient grow as they would in the pig for the first two weeks after transplantation. After this time there is a reduction in the rate of increase in the length of the xenograft. Over the same period, changes in weight are greatly increased by the presence of rejection. This observational study supports the notion that regulation of growth of a xenotransplanted porcine kidney occurs.

Osteoclastic tartrate-resistant acid phosphatase (Acp 5): its localization to dendritic cells and diverse murine tissues

Tartrate-resistant acid phosphatase (TRAP) is a histochemical marker of the osteoclast. It is also characteristic of monohistiocytes, particularly alveolar macrophages, and is associated with diverse pathological conditions, including hairy cell leukemia and AIDS encephalopathy. To study the biology of this enzyme, we investigated its expression and activity in mouse tissues. Confocal fluorescence studies showed that TRAP is localized to the lysosomal compartment of macrophages. In adult mice, high activities of the enzyme were demonstrated in bone, spleen, liver, thymus, and colon, with lower amounts in lung, stomach, skin, brain, and kidney. Trace amounts were detected in testis, muscle, and heart. Expression of TRAP mRNA was investigated in tissue sections by in situ hybridization and protein expression was monitored by histochemical staining or immunohistochemically. TRAP is widely expressed in many tissues, where it is associated with cells principally originating from the bone marrow, including those of osteoclast/macrophage lineage. The cellular distribution of TRAP mRNA and enzyme antigen in the tissues corresponds closely to that of cells staining with an antibody directed to the CD80 (B7) antigen. Therefore, to confirm its putative localization in dendritic cells, isolated bone marrow dendritic cells were matured in culture. These co-stained strongly for TRAP protein and the CD80 antigen. These studies demonstrate that TRAP is a lysosomal enzyme that is found in diverse murine tissues, where it is expressed in dendritic cells as well as osteoclasts and macrophages, as previously shown. (J Histochem Cytochem 48:219-227, 2000)

Recent advances in the molecular basis of TNF signal transduction

Substantial progress has been made in the last decade toward defining the signaling pathways that can be activated by TNF and identifying the relevant intracellular signaling molecules. The in vivo consequences of targeted disruption of many of the genes encoding proteins involved in TNF signaling (as discussed in this review) are quite different from those observed for knockout mutations of TNF and the TNF receptors (Erickson et al, 1994; Marino et al, 1997; Rothe et al, 1993) that use these molecules. This suggests that there is still much to be learned about the mechanisms for determining specificity in signaling. The ability to specifically manipulate the involvement of these molecules in TNF signaling, without affecting other pathways, may provide new therapeutic approaches to the many diseases in which TNF has a crucial role.

Tumor necrosis factor induces distinct patterns of caspase activation in WEHI-164 cells associated with apoptosis or necrosis depending on cell cycle stage

TNF is unusual among the death receptor ligands in being able to induce either apoptotic or necrotic cell death. We have observed that in WEHI 164 fibrosarcoma, cells the mode of TNF-induced cell death is dependent on the stage of the cell cycle. Cells arrested in G(0)/G(1) undergo necrosis, while those progressing through the cell cycle undergo apoptosis. TNF induces caspase activity in both settings, and the broad spectrum caspase inhibitor zVAD-fmk inhibits this activity and blocks both TNF-induced apoptosis and necrosis. Inhibition of oxygen radical accumulation does not block cytotoxicity. The presence and activation of specific caspases were examined by Western blotting. The procaspase-8a isoform was down-regulated in proliferating cells. Procaspases-8b and -7 were cleaved during TNF-induced apoptosis but not necrosis. Thus, a different pattern of caspase expression and activation occurs dependent on the cell cycle and which may determine the mode of cell death.

TNF recruits TRADD to the plasma membrane but not the trans-Golgi network, the principal subcellular location of TNF-R1

The subcellular localization of TNF-R1 to the Golgi apparatus, initially observed in endothelial cells, has been confirmed using transfection of bovine aortic endothelial cells with a human TNF-R1 expression plasmid. The subcellular interactions of TNF-R1 and the TRADD (TNFR-associated death domain protein) adaptor protein have been analyzed in the human monocyte cell line U937 and the human endothelial cell line ECV304 by confocal immunofluorescence microscopy and by Western blot analysis of fractionated cell extracts. In untreated cells, in which TNF-R1 is found on the cell surface but principally localizes to the trans-Golgi network, TRADD is concentrated in the cis- or medial-Golgi region, but separates from the Golgi during cell fractionation. Coimmunoprecipitation studies have shown that TRADD binds to TNF-R1 within 1 min of TNF treatment in a cell fraction-containing plasma membrane. This association is followed by a gradual dissociation, which is prevented if receptor-mediated endocytosis is inhibited by hypertonic medium. In contrast, no association is detected between TRADD and TNF-R1 in the Golgi in response to exogenous TNF at any time examined. These results suggest that although TNF-R1 is predominantly a Golgi-associated protein and TRADD also localizes to the Golgi region, exogenous TNF causes TRADD to bind to TNF-R1 only at the plasma membrane.

Tumor necrosis factor is delivered to mitochondria where a tumor necrosis factor-binding protein is localized

The roles of the known tumor necrosis factor (TNF) receptors (TNFR-I and TNFR-II) and their associated signaling pathways in mediating the diverse actions of TNF remain incompletely defined. We have found that a proportion of exogenous TNF is delivered to mitochondria as well as to lysosomes. Using confocal and immunoelectron microscopy and Western blotting of subcellular fractions, we have identified a 60-kd protein in the inner mitochondrial membrane that is recognized by a monoclonal antibody to TNFR-II. In isolated mitochondria, this protein binds [125I]-TNF. This provides evidence of a mitochondrial binding protein for an extracellular ligand and demonstrates the presence of a pathway capable of delivering TNF from the cell surface to mitochondria. These findings suggest that TNF effects on cells may be due in part to a direct effect on mitochondria.

Tumor necrosis factor-induced cytotoxicity is not related to rates of mitochondrial morphological abnormalities or autophagy-changes that can be mediated by TNFR-I or TNFR-II

Tumor necrosis factor (TNF) may cause apoptosis or necrosis and induces mitochondrial changes that have been proposed to be central to cytotoxicity. We report similar patterns of TNF-induced mitochondrial morphological alterations and autophagy in cell types with differing sensitivity to TNF-induced cytotoxicity. Specific ligation of TNFR-I or TNFR-II induces different rates of apoptosis and mitochondrial morphological change, but similar rates of autophagy. These changes do not invariably lead to cell death, and survival or progression to apoptosis or necrosis following TNF exposure may depend in part on the extent of mitochondrial damage and/or the autophagic capacity of the cell.

The N-terminal domains target TNF receptor-associated factor-2 to the nucleus and display transcriptional regulatory activity

The subcellular localization of the TNF receptor-associated factor-2 (TRAF2) adaptor protein in human endothelial cells, which mediates proinflammatory responses of TNF, has been analyzed by confocal immunofluorescence microscopy and by Western blotting of fractionated cell extracts. Rabbit antisera reactive with either amino- or carboxyl-terminal TRAF2 peptides frequently but not uniformly stain nuclei of cultured HUVEC or the established human endothelial cell line, ECV304. However, Western blotting reveals significant heterogeneity in the reactivities of these polyclonal Abs. Transiently transfected HUVEC expressing FLAG epitope-tagged TRAF2 consistently show prominent nuclear localization, and deletion mutants of TRAF2 identify the portion of the molecule responsible for nuclear localization as the amino-terminal ring finger domain. TNF treatment does not appear to influence the localization of endogenous or transfected TRAF2 protein. Transfection of the amino-terminal half of the TRAF2 molecule, containing the ring and zinc finger domains, which localizes to the nucleus, results in activation of E-selectin but not of NF-kappaB promoter-reporter gene transcription or of c-Jun N-terminal kinase activation. These observations suggest that TRAF2 may reside in the nucleus and directly regulate transcription, independent of its role in cytoplasmic signal transduction.

Prolonged cytokine exposure causes a dynamic redistribution of endothelial cell adhesion molecules to intercellular junctions

After 4 hours of treatment with TNF, newly synthesized endothelial leukocyte adhesion molecule 1, vascular cell adhesion molecule 1, and intercellular adhesion molecule 1 molecules are diffusely expressed on the apical surface of cultured umbilical vein endothelial cells. Such cells maintain the epithelioid, cobblestone appearance of untreated endothelial cells and display cytoskeletal actin largely arranged in dense peripheral bands. After 24 to 72 hours of treatment with TNF, cells become elongated and rearrange their actin filaments into longitudinal stress fibers. At this time, intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 remain elevated but redistribute to the cell junctions. Intercellular adhesion molecule 2, beta 1 integrins, and beta 3 integrins also redistribute to cell junctions in TNF-treated cultures. IFN-gamma produces morphologic changes similar to those induced by TNF but does not cause surface protein redistribution. Cells treated with TNF plus IFN-gamma become even more elongated and display TNF-like redistributions. We conclude that TNF activates a program of membrane protein redistribution, and we speculate that this dynamic redistribution of adhesion molecules to cell junctions may contribute to the recruitment of leukocytes to sites of inflammation.

"Cytosolic" phospholipase A2 is in the nucleus of subconfluent endothelial cells but confined to the cytoplasm of confluent endothelial cells and redistributes to the nuclear envelope and cell junctions upon histamine stimulation

The synthesis of arachidonic acid metabolites is initiated by activation of the sn-arachidonyl-dependent, 85-kd "cytosolic" phospholipase A2 (cPLA2) enzyme. We have investigated the subcellular localization of cPLA2 in resting and histamine-treated human and bovine endothelial cells (EC) using confocal immunofluorescence microscopy. In tightly confluent EC, cPLA2 was primarily localized in the cytoplasm. Surprisingly, in subconfluent EC, cPLA2 was also prominently located within the cell nucleus. By immunoblotting of cell lysates after SDS-PAGE, the cytoplasmic molecular species in subconfluent cells displayed the characteristic Mr 110,000, whereas nuclear extracts contained a predominant Mr 70,000. Nuclear localization of cPLA, in subconfluent EC is independent of cell cycle because it was observed in growth-arrested cells as well as in dividing cells. Nuclear localization was also observed in subconfluent MDCK and HeLa cells where, in contrast to EC, it persisted in tightly confluent monolayers. Treatment of subconfluent EC with histamine caused a rapid, dose-dependent redistribution of cPLA2, from the nucleus to the nuclear envelope. The same treatment of confluent EC produced translocation of cytoplasmic enzyme to the nuclear envelope and to the plasma membrane at the intercellular junctions. The cell density dependence of cPLA2, localization may contribute to altered arachidonic acid metabolism in injured vessels as compared with quiescent vessels.

Coping, drinking motives, goal attainment expectancies and family models in relation to alcohol use among college students

Associations between coping responses, drinking motivations, expectations of meeting social and academic goals, and family of origin problem drinking and measures of college students' quantity/frequency of alcohol use and social complications of alcohol use were investigated in a sample of 218 college students. Positive associations were found between "emotion-focused" forms of coping such as detachment and the criterion measures, whereas "problem-focused coping" was not significantly associated with quantity/frequency of alcohol use or drinking complications. Positive correlations were also found between drinking motives, goal attainment expectancies and family models measures and the criterion measures. Regression models constructed for alcohol quantity/frequency and drinking complications implicated the total number of drinking motives, family models of problem drinking and the coping strategy of self-blame as strongly related to criterion measures. Positive social drinking motives and coping by seeking social support were implicated as possible protective factors.

Illustrating caffeine's pharmacological and expectancy effects utilizing a balanced placebo design

Caffeine consumption, a ubiquitous cultural phenomenon with significant health implications may be governed by some of the same principles which affect other drug use [1]. We hypothesized that pharmacological and expectancy effects may be two of those principles. A balanced placebo design was used with 100 male undergraduates to separate caffeine's active drug effects from the expectancy of having consumed caffeine on mood, performance, and physiological measures. The manipulation of expectancies was highly effective on subjects' judgments of caffeine dosage, regardless of actual caffeine content. As predicted, expectancy set and caffeine content appeared equally powerful, and worked additively, to affect subjects' ratings of how much the coffee influenced their mood and performance. Main effects on systolic and diastolic blood pressure, pulse rate, and a fatigue measure were found for caffeine vs. no caffeine groups only. Additional increases in diastolic blood pressure for smokers were noted within the caffeine-receiving conditions. Results are discussed with heuristic and health implications.

Precursors, mediators and problem drinking: path analytic models for men and women

Direct and mediating effects of mechanisms hypothesized to account for the association between parental problem drinking and later problem drinking by offspring were investigated. Specifically, a "negative affect" submodel was proposed in which family environment, self-esteem, alienation, likelihood of attaining valued goals, psychopathology, and drinking motives would all mediate the parental-problem-drinking to offspring-problem-drinking relationship. Subjects were 350 female and 300 male, eighteen to twenty-three year-old undergraduates. Multivariate analyses of variance revealed differences in a majority of study variables between subjects with and without a family history of parental problem drinking. Structural equation modeling identified associations separately for paternal and maternal problem drinking and offspring alcohol use. Direct and mediating effects were tested with path analysis separately for male and female respondents. Both parents' drinking affected later problematic alcohol use by offspring. The opposite-sexed parents' drinking had a more negative influence on subjects' self-perception. For both men and women, parental problem drinking reduced adaptive family functioning, which was subsequently linked to problem personality characteristics, more personal drinking motives, and greater alcohol involvement. Specific mediating mechanisms varied between models for each sex. Implications regarding these models are discussed.

Hydrogen peroxide-induced endothelial retraction is accompanied by a loss of the normal spatial organization of endothelial cell adhesion molecules

Treatment of confluent monolayers of human umbilical vein endothelial cells with sublethal concentrations of hydrogen peroxide (H2O2) produces reversible cell retraction that opens gaps between adjacent cells. Despite the retraction, adjacent cells remain in contact through a network of dendrite-like processes. Retraction depends on cellular metabolism but not new protein synthesis or protein kinase C. Shape changes induced by H2O2 are accompanied by partial redistribution of actin filaments from the cell periphery in resting endothelial cells to a tangled network of centrally located filaments in H2O2-treated endothelial cells. This change in actin organization is associated with a loss of the normal distribution pattern of surface protein expression. Specifically, beta 1 and beta 3 integrins partly escape from focal adhesion plaques and migrate to the lateral and apical surface of the cell; PECAM-1 redistributes from the lateral borders to the basal surface; and ICAM-1 and ICAM-2 spread from apical caps to the basal surface and to the dendrite-like processes. The likely consequence of endothelial retraction accompanied by abnormal membrane protein distribution is a loss of normal endothelial cell functions. These changes are best considered manifestations of H2O2-induced sublethal injury that may cause endothelial dysfunction.

Disparate localization of 55-kd and 75-kd tumor necrosis factor receptors in human endothelial cells

We have used confocal immunofluorescence microscopy and immunogold electron microscopy to localize tumor necrosis factor (TNF) receptors in cultured human umbilical vein endothelial cells. The 75-kd receptor is largely expressed on the cell surface and undergoes endocytosis and transport to lycosomes through coated pits and coated vesicles. TNF may accelerate receptor clustering and internalization. The 55-kd receptor is expressed at much lower levels on the cell surface than the 75-kd receptor but is more abundant overall. It is predominantly localized to the Golgi apparatus and, to a lesser extent, cytoplasmic vacuoles. The cellular distribution of the 55-kd receptor is largely unaffected by TNF. These results have implications for TNF-mediated endothelial cell activation and for interactions between 75- and 55-kd TNF receptors.

Endothelial cell activation in patients with systemic vasculitis

Vascular endothelial cells respond in vitro to a number of stimuli, and in particular to cytokines, by undergoing functional and morphological alterations which endow them with the capacity to promote inflammatory reactions. We studied this process of endothelial cell activation in 20 skin biopsies from 18 patients with systemic vasculitis. At sites of cutaneous inflammation, blood vessels were lined with swollen endothelial cells which expressed increased levels of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), and were associated with a mononuclear cell inflammatory infiltrate. Neutrophil infiltration was only found in the presence of endothelial leucocyte adhesion molecule-1 (ELAM-1), which was expressed in 15/20 biopsies. ELAM-1 and VCAM-1 were associated with the presence of inflammatory cytokines which induce expression of these molecules in cultured endothelial cells. Endothelial activation in vivo appears to parallel that observed in vitro, and is likely to be important in determining the nature of an inflammatory response.

Four different classes of inhibitors of receptor-mediated endocytosis decrease tumor necrosis factor-induced gene expression in human endothelial cells

We have investigated the relationship between receptor-mediated endocytosis of TNF and TNF-induced gene expression in cultured human endothelial cells. Exposure of cells to hypertonicity, to cytoplasmic acidification, to treatment with phenylarsine oxide, or to treatment with primary amines such as putrescine or dansylcadaverine each inhibited receptor-mediated endocytosis by 30 to 75%, as measured by uptake of acetylated Dil-low density lipoprotein or of 125I-TNF. All four treatments also inhibited TNF-induced surface expression of ELAM-1 by 50 to 100%. Among these four treatments, only hypertonicity inhibited pinocytosis, as measured by uptake of fluorescein-BSA, and only phenylarsine oxide irreversibly inhibited protein synthesis, as measured by [35S]methionine incorporation. Notably, acidification or treatment with primary amines selectively inhibited the response to TNF, compared with the response to PMA, a drug that induces ELAM-1 through a pathway that bypasses surface receptors. Primary amines, which can be used for sustained periods under physiologic culture conditions without causing toxicity, were investigated further. Pretreatment of endothelial cells with 10 mM putrescine or 100 microM dansylcadaverine also inhibited TNF induction of ICAM-1 expression and VCAM-1 expression. Primary amines also inhibited IL-1-induced increases in ELAM-1, ICAM-1, and VCAM-1 measured 4 to 6 h after treatment and inhibited IFN-beta- and IFN-gamma-mediated induction of class I MHC molecules and IFN-gamma-mediated induction of class II MHC molecules measured 72 h after treatment with cytokine. Levels of mRNA encoding cytokine-inducible molecules were also selectively reduced by primary amines. A constitutively expressed surface molecule, gp96, was not affected in the same cells. These data are consistent with a role for receptor-mediated endocytosis in TNF-mediated gene induction and suggest a new potential target for anti-inflammatory therapy.

Four different classes of inhibitors of receptor-mediated endocytosis decrease tumor necrosis factor-induced gene expression in human endothelial cells

We have investigated the relationship between receptor-mediated endocytosis of TNF and TNF-induced gene expression in cultured human endothelial cells. Exposure of cells to hypertonicity, to cytoplasmic acidification, to treatment with phenylarsine oxide, or to treatment with primary amines such as putrescine or dansylcadaverine each inhibited receptor-mediated endocytosis by 30 to 75%, as measured by uptake of acetylated Dil-low density lipoprotein or of 125I-TNF. All four treatments also inhibited TNF-induced surface expression of ELAM-1 by 50 to 100%. Among these four treatments, only hypertonicity inhibited pinocytosis, as measured by uptake of fluorescein-BSA, and only phenylarsine oxide irreversibly inhibited protein synthesis, as measured by [35S]methionine incorporation. Notably, acidification or treatment with primary amines selectively inhibited the response to TNF, compared with the response to PMA, a drug that induces ELAM-1 through a pathway that bypasses surface receptors. Primary amines, which can be used for sustained periods under physiologic culture conditions without causing toxicity, were investigated further. Pretreatment of endothelial cells with 10 mM putrescine or 100 microM dansylcadaverine also inhibited TNF induction of ICAM-1 expression and VCAM-1 expression. Primary amines also inhibited IL-1-induced increases in ELAM-1, ICAM-1, and VCAM-1 measured 4 to 6 h after treatment and inhibited IFN-beta- and IFN-gamma-mediated induction of class I MHC molecules and IFN-gamma-mediated induction of class II MHC molecules measured 72 h after treatment with cytokine. Levels of mRNA encoding cytokine-inducible molecules were also selectively reduced by primary amines. A constitutively expressed surface molecule, gp96, was not affected in the same cells. These data are consistent with a role for receptor-mediated endocytosis in TNF-mediated gene induction and suggest a new potential target for anti-inflammatory therapy.

Endothelial activation by hydrogen peroxide. Selective increases of intercellular adhesion molecule-1 and major histocompatibility complex class I

Products of activated leukocytes may alter vascular endothelial cell (EC) function. For example, ECs respond to leukocyte-derived cytokines, such as tumor necrosis factor (TNF) or interleukin-1, by reversibly altering levels of expression of specific gene products that promote inflammation. In contrast, hydrogen peroxide, a product of TNF-activated neutrophils, can produce irreversible EC injury and death. In this study, we have investigated the effects of subinjurious concentrations of hydrogen peroxide on EC inflammatory functions. Treatment with 50 to 100 mumol/L hydrogen peroxide selectively increases surface expression of intercellular adhesion molecule-1 and major histocompatibility complex class I, but not endothelial leukocyte adhesion molecule-1 (also known as E-selectin), vascular cell adhesion molecule-1, or gp96, a constitutively expressed EC surface protein. Increased major histocompatibility complex class I and intercellular adhesion molecule-1 surface expression is associated with specifically increased messenger RNA levels, suggesting selective endothelial gene activation. Hydrogen peroxide does not activate the transcription factor Nuclear Factor kappa B, an important mediator of TNF-induced gene expression. Co-treatment with hydrogen peroxide inhibits TNF-induced gene expression at 4 hours, an effect which can be attributed to reversible inhibition of TNF binding to EC surface receptors. Hydrogen peroxide also antagonizes the actions of interleukin-1. At 24 hours, TNF and hydrogen peroxide produce, at most, additive increases in intercellular adhesion molecule-1 and major histocompatibility complex class I. These results suggest that subinjurious concentrations of hydrogen peroxide can activate endothelium and that the effects of hydrogen peroxide on ECs differ from those of inflammatory cytokines.

Multiple Pest Interactions in Soybean: Effects on Heterodera glycines Egg Populations and Crop Yield

Population changes of Heterodera glycines eggs on soybean in small field plots were influenced by the lepidopterous insect pest, Helicoverpa zea; however, few effects on eggs due to the presence of annual weeds were detected. Soybeans defoliated 15-35% by H. zea during August remained green and continued to produce new flowers and pods later into the season than soybeans without H. zea, resulting in higher numbers of H. glycines eggs at harvest on insect-defoliated soybeans. Final H. glycines populations also were influenced by soil population density (Pi) of the nematode at planting. Fecundity of H. glycines was generally greater at the undetected and low Pi than at high Pi levels. Soybean yields were suppressed 12, 22, and 30% by low, moderate, and high H. glycines Pi, respectively. When weed competition and H. zea feeding damage effects were added, yields were suppressed 34, 40, and 57% by the three respective nematode Pi levels. Effects among the three pests on soybean yield were primarily additive.

Impaired nutritive skeletal muscle blood flow in patients with chronic renal failure

1. The possibility that abnormalities of skeletal muscle may limit the exercise tolerance of patients with chronic renal failure was investigated in patients undergoing regular haemodialysis. 2. Blood flow to the calf, a vascular bed consisting predominantly of skeletal muscle, was measured in six patients before and after exercise and compared with values obtained from 12 control subjects. 3. The patients were limited on exertion and had an abnormal response of calf blood flow to bicycle exercise. Resting calf blood flow was similar in patients and control subjects, but the mean increase in calf blood flow in response to submaximal exercise was 0.55 (SEM 0.12) ml min-1 100 ml-1 in the patients and 1.43 (SEM 0.17) ml min-1 100 ml-1 in the control subjects. The increase after symptom-limited maximal exercise was 1.50 (SEM 0.80) ml min-1 100 ml-1 in the patients and 4.20 (SEM 0.40) ml min-1 100 ml-1 in the control subjects. 4. Skeletal muscle biopsies from eight haemodialysis patients were studied by histochemistry and electron microscopy. 5. Oxidative enzyme activity was increased and there were large subsarcolemmal aggregates of structurally normal mitochondria. Necrotic capillaries were observed as empty basement membrane tubes containing fragments of degenerating endothelium. 6. The changes were compatible with a response to a chronic reduction in skeletal muscle blood flow.