Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums.

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 µm diameter hot core.

Long term follow-up of patients with chronic hepatitis C treated with interferon alpha.

Interferon alpha (IFN alpha) treatment for chronic hepatitis C induces a sustained biochemical and virological response at six months after completing 24 weeks of therapy in approximately 10% of patients. The long term durability of this 'sustained' response is still controversial. The aim of this multicentre study was to assess the long term virological response in patients considered to have achieved a sustained biochemical response six months after completing IFN treatment. The majority (36 of 41) of the sustained responders identified had been treated for six months with IFN therapy. Twenty-nine of the 41 patients (70%) had undetectable hepatitis C virus (HCV) RNA after a mean follow-up of 38 months after cessation of treatment (range six to 92 months). All but one of those 29 individuals had normal serum alanine aminotransferase (ALT) levels. Of the 16 patients (out of 41) who had been tested for HCV RNA six months after treatment, HCV RNA remained undetectable in 14 (88%) at final follow-up. Serum ALT values in the 11 of 12 patients whose HCV RNA was positive at final follow-up were lower than pretreatment values, and in six cases were within the normal range. The long term sustained virological response in those considered a 'sustained responder' six months after receiving only six months of IFN is high. Measurement of ALT is an unreliable marker of sustained response to therapy.

Effects of tacrolimus on hyperlipidemia after successful renal transplantation: a Southeastern Organ Procurement Foundation multicenter clinical study.

BACKGROUND: Tacrolimus has been shown to have a less adverse effect on the lipid profiles of transplant patients when the drug is started as induction therapy. In order to determine the effect tacrolimus has on lipid profiles in stable cyclosporine-treated renal transplant patients with established hyperlipidemia, a randomized prospective study was undertaken by the Southeastern Organ Procurement Foundation. METHODS: Patients of the 13 transplant centers, with cholesterol of 240 mg/dl or greater, who were at least 1 year posttransplant with stable renal function, were randomly assigned to remain on cyclosporine (control) or converted to tacrolimus. Patients converted to tacrolimus were maintained at a level of 5-15 ng/ml, and control patients remained at their previous levels of cyclosporine. Concurrent immunosuppressants were not changed. Levels of total cholesterol, triglycerides, total high-density lipoprotein, low-density lipoprotein (LDL), very-low-density lipoprotein, and apoproteins A and B were monitored before conversion and at months 1, 3, and 6. Renal function and glucose control were evaluated at the beginning and end of the study (month 6). RESULTS: A total of 65 patients were enrolled; 12 patients failed to complete the study. None were removed as a result of acute rejection or graft failure. Fifty-three patients were available for analysis (27 in the tacrolimus group and 26 controls). Demographics were not different between groups. In patients converted to tacrolimus treatment, there was a -55 mg/dl (-16%) (P=0.0031) change in cholesterol, a -48 mg/dl (-25%) (P=0.0014) change in LDL cholesterol, and a -36 mg/dl (-23%) (P=0.034) change in apolipoprotein B. There was no change in renal function, glycemic control, or incidence of new onset diabetes mellitus in the tacrolimus group. CONCLUSION: Conversion from cyclosporine to tacrolimus can be safely done after successful transplantation. Introduction of tacrolimus to a stable renal patient does not effect renal function or glycemic control. Tacrolimus can lower cholesterol, LDL, and apolipoprotein B. Conversion to tacrolimus from cyclosporine should be considered in the treatment of posttransplant hyperlipidemia.

The high grade match kidney sharing algorithm of the South-Eastern Organ Procurement Foundation (SEOPF): altering recipient demographics through improved matching.

BACKGROUND: Studies of kidneys shared through the South-Eastern Organ Procurement Foundation (SEOPF) have shown that regional organ procurement (ROP) trays can predict negative crossmatch in highly sensitized patients when the HLA match is of a high grade. In an attempt to offer more well-matched kidneys to highly sensitized patients, SEOPF organized the High Grade Match (HGM) Program. METHODS: This United Network for Organ Sharing (UNOS)-approved allocation variance requires mandatory sharing of all kidneys by participating centers after UNOS mandatory sharing requirements have been met. The HGM levels of sharing are: (1) 0 A,B mismatch (MM); panel-reactive antibody (PRA) > or = 40%; negative ROP crossmatch; (2) 0 B,DR MM with > or = 40% PRA; negative ROP crossmatch; (3) 0 B,DR MM with PRA < 40%. Non-HGM cadaveric transplants at the same participating centers--locally or distally procured--serve as the control group. RESULTS: During the first 18 months of this program, the 23 participating centers shared 124 kidneys of the 1592 that were available. Well-matched kidneys (two mismatches or less) accounted for 91.1% in the HGM group, but only 19% of the controls (P<0.0001). Highly sensitized patients (PRA > or = 40%) represented 13.8% of the HGM group, but only 3.3% of the non-HGM group (P<.0001). With HGM kidneys, there was a shift in recipient demographics. Patients with blood group O, female patients, older patients, and retransplanted patients all accounted for significantly larger percentages of the HGM group compared with the non-HGM control group. The racial composition of the recipients of high-grade matches was, however, no different than that of the control recipients at the same centers. CONCLUSION: The HGM Program resulted in longer ischemia times, but graft survival was not affected. The 1-year actuarial graft survival rate (Kaplan-Meier) for HGM kidneys was not different from the control cadaveric graft survival rate. By sharing kidneys based on improved HLA matches with consideration for high PRA, the HGM Program offered more transplant opportunities to women, blood group O recipients, retransplants, and older patients.

Artemisinin enhances heme-catalysed oxidation of lipid membranes.

Artemisinin, a sesquiterpene endoperoxide derived from a traditional Chinese herbal remedy for fevers, is a promising new antimalarial drug, particularly useful against multidrug resistant strains of P. falciparum. Despite widespread clinical use, its mode of action remains uncertain. We investigated whether its antimalarial properties could be explained by an ability to enhance the redox activity of heme, formed in the parasite food vacuole from digested hemoglobin. Artemisinin caused a sustained threefold increase, followed by a gradual decline, in the peroxidase activity of heme. It also enhanced the ability of heme to oxidize membrane lipids about sixfold. An unexpected finding was the potentiation of heme-catalysed membrane lipid oxidation by Vitamin E. The changes in redox-catalytic activity induced by artemisinin were paralleled by major changes in the absorption spectrum of heme, culminating in loss of the Soret band. We propose a model in which artemisinin binds irreversibly to heme in the parasite food vacuole, preventing its polymerization to chemically inert hemozoin, and promoting heme-catalysed oxidation of the vacuolar membrane by molecular oxygen, which leads, ultimately, to vacuole rupture and parasite autodigestion.

The chemical mechanism of beta-haematin formation studied by Mössbauer spectroscopy.

Spontaneous formation of beta-haematin (malaria pigment) from haematin in acetate solution follows pseudo-zero-order and not autocatalytic kinetics. Acetate appears to facilitate the reaction by solubilizing the haematin and acting as a phase-transfer catalyst, a role which, in vivo, could be fulfilled by carboxylic acids or amino acids.

The iron environment in heme and heme-antimalarial complexes of pharmacological interest.

Mössbauer spectroscopy has been utilized to probe the electronic environment of iron in a number of Ferriprotoporphyrin IX complexes of relevance to malaria. The markedly different iron environments found for the complexes of hemin with quinine, chloroquine, and the Chinese herbal antimalarial artesunate suggest that these compounds act by protecting the heme from polymerization to insoluble hemozoin, and by facilitating the transport of the protected heme to the food vacuole membrane where it is able to exercise its cytotoxic redox catalytic activity. Mössbauer parameters determined here for purified malaria pigment and synthetic beta-hematin confirm the chemical identical-ness of these species. The Mössbauer spectra of the complexes are discussed in light of the proposed structures of the complexes.

Reaction between ferriprotoporphyrin IX and the antimalarial endoperoxide artesunate gives an intermediate species with enhanced redox catalytic activity.

The kinetics of the reaction between ferri(Fe(III) protoporphyrin IX (haemin) and the potent sesquiterpene endoperoxide antimalarial artesunate are shown to be consistent with a three-step, two-intermediate mechanism, with the final product possessing a degraded tetrapyrrole ring system. Microscopic rate constants for the mechanism have been evaluated. The redox catalytic capability of the haem artesunate complex is shown to be approximately fourfold that of haemin alone, suggesting a possible mechanism of action of the drug.

Dangerousness and command hallucinations: an investigation of psychotic inpatients.

Forensic consultations with psychotic inpatients frequently include issues of risk management, such as dangerousness and civil commitment. An important dimension of these consultations is the role of command hallucinations in producing an increased risk of aggressive behavior. In the present study, psychotic patients with command hallucinations (N = 27) were compared with patients with other hallucinations (N = 27) and with other psychotic patients (N = 30). The groups did not differ on aggressive behavior or most nonhallucinatory symptoms. However, most patients (84.0%) with command hallucinations had recently obeyed them. Among those with command hallucinations, almost one-half had heard and attempted to obey messages of self-harm during the last month.

Inhibition of mammalian protoporphyrinogen oxidase by acifluorfen.

We have studied the kinetics of the inhibition of mitochondrial protoporphyrinogen oxidase (PPO) from liver and placenta of 3 mammalian species by the diphenyl ether herbicide acifluorfen (AF). AF competitively inhibited PPO from human liver and placenta, mouse liver and pig placenta with respect to its substrate protoporphyrinogen. In contrast, mixed-type inhibition was shown for pig liver. The differing results shown in pig liver may point to structural differences in PPO derived from different species and tissues. We have also compared the effects of AF on the function of PPO in human lymphoblasts from normal subjects and those with variegate porphyria, an inherited disorder of PPO. Competitive inhibition was shown for both and there were no significant differences in the values of Ks or Ki.

Quinoline anti-malarial drugs inhibit spontaneous formation of beta-haematin (malaria pigment).

Polymerisation of haematin to beta-haematin (haemozoin or malaria pigment) in acidic acetate solutions was studied using infrared spectroscopy. The reaction was found to occur spontaneously between 6 and 65 degrees C, in 0.1-4.5 M acetate and pH 4.2-5.0. The anti-malarial drugs quinine, chloroquine and amodiaquin were found to block spontaneous beta-haematin formation, while the anti-malarially inactive 9-epiquinine and 8-hydroxyquinoline had no effect on the reaction, as did primaquine, a drug which is active only against exo-erythrocytic stages of infection. It is argued that the intra-erythrocytically active anti-malarial agents act by binding to haematin, blocking beta-haematin formation and leaving toxic haematin in the parasite food vacuoles.

Mössbauer spectra of the heme peptide (HP) 1-50 and the heme peptide:non-heme peptide (NHP) non-covalent complex 1-50:51-104 derived from cytochrome c: evidence for cytochrome c iron site solvation in aqueous solution.

Mössbauer spectroscopic studies on a heme peptide (HP) derived from cytochrome c and on the HP recombined non-covalently with the remaining cleaved section are reported. The results suggest that the environment of the heme site in the known crystal structure of cytochrome c may differ in detail from the environment of the heme in the working protein.

Haem peptide/protein interaction. Part 6: The kinetic mechanisms of the interactions with, and inhibition of enzymic activity of the human erythrocyte glutathione S-transferase isoenzyme rho (p), by haem octa-, nona-, and undecapeptides MP-8/-9/-11.

The binding of the cytochrome-c derived haem peptides microperoxidase-8, -9, and -11 (MP-8, -9, and -11) to the human erythrocyte glutathione S-transferase rho (GST-p) enzyme is demonstrated. Inhibition by the haem peptides of the enzymic conjugation of glutathione (GSH) with the electrophilic cosubstrate 1-chloro-2, 4-dinitrobenzene (CDNB) is mixed-type with respect to CDNB, and Ki, the inhibition constant, increases with increasing length of the peptide chain. The results obtained here for the GST-p are compared to those published recently for the previously-supposed identical isoenzyme human placental GST-pi.

Haem-peptide-protein interactions: Part 5. The haem undecapeptide microperoxidase-11 (Fe3+MP-11)/human serum albumin (HSA) reaction in aqueous methanolic solution. A simple system demonstrating the effect of hydrophobicity on ligand release from a ligand-protein complex.

Previous studies of the interaction of the haem undecapeptide (MP-11) with lipidated human serum albumin in aqueous solution have been extended to a range of MeOH/H2O solution compositions. It is demonstrated that the kinetic mechanism for the interaction does not change from a simple second- and first-order reversible scheme as XMeOH is increased, however while k1--the association rate constant is essentially invariant with XMeOH, K-1 increases some 600-fold over the range studied. The result is interpreted in terms of increased solvational stabilization of MP-11 and transition state as XMeOH increases and it is noted that the system provides a simple demonstration of the effect of hydrophobicity on facilitating transported ligand release from ligand/carrier protein molecules.

1-Chloro-2,4-dinitrobenzene-mediated irreversible inactivation of acidic glutathione S-transferases. Inactivation mechanism--a saturation-type or simple second-order kinetic process?

A critical analysis of the inactivation kinetics exhibited by the acidic human glutathione S-transferase (GST) enzymes is presented. Data on the 1-chloro-2,4-dinitrobenzene (CDNB)-facilitated inactivation of human placental GST pi have been utilized in conjunction with published inactivation data from the literature to answer the following two questions: (a) do the inactivation kinetics deviate significantly from a simple pseudo first-order model? (b) What is the kinetic mechanism of irreversible electrophilic co-substrate-mediated inactivation of human acidic GSTs? Inactivation of human placental GST pi in the presence of 7-aminocephalosporanic acid, a non-electrophilic non-substrate ligand, is characterized and shown to occur via a process analogous to the second mechanism proposed for CDNB inactivation of the enzyme, namely: pH- and [ligand]-independent solvational inactivation.

A comparative study of pH/activity profiles for the anaerobic H2O2 and alkyl hydroperoxide supported N demethylation of N methylaniline catalyzed by alkaline haematin and microsomal cytochrome P-450.

A comparative study of the effect of pH on haemin-mediated H2O2 and alkyl hydroperoxide-supported N-demethylation of N-methylaniline and the corresponding cytochrome P-450 mediated process has been carried out. This extends previous studies and provides quantitative evidence that the same active oxygen species are involved in both the enzymic and metalloporphyrin mediated processes. Furthermore, this evidence clearly indicates that the environment at the point of catalysis in the enzyme active site differs considerably from that of the bulk solution.

Factors affecting the inactivation of human placental glutathione S-transferase pi. The kinetic mechanism and pH-dependence of solvational and 1-chloro-2,4-dinitrobenzene-mediated inactivation of the enzyme.

The kinetics of the inactivation of human placental GSH S-transferase pi has been studied at 25 degrees in the pH range 6.5 less than or equal to pH less than or equal to 9. At pH values less than or equal to 7.0 the inactivation of GSH S-transferase pi incubated in the absence of GSH and (i) in the absence or (ii) in the presence of CDNB (0-1.5 X 10(-3) mol/dm3) exhibited pseudo first-order kinetics with kobs for (i) and (ii) approximately equal (approximately 0.002 sec-1). The extent of inactivation in (i) approached a limiting value of 50% at infinite dilution of the enzyme; while in the presence of CDNB the extent of inactivation approached 100%. At any given pH such that 7 less than pH less than or equal to 9 the pseudo first-order inactivation rate constant, kobs, exhibits a linear dependence on [CDNB] (Eqn 1): kobs = k1 + k2 [CDNB] (1) where k1 is invariant with pH and approximately equal to 0.002 sec-1. The first-(k1) and second-(k2)-order components of kobs suggest at least two mechanisms for the inactivation of GST by CDNB, these are: (i) a pH-invariant facilitation of solvational inactivation and (ii) a pH-dependent nucleophilic reaction of a thiol group (pKa = 8.85 +/- 0.08) at or spatially close to the active site of the enzyme. A mechanistic rationale for the enzyme functioning as a dimer is discussed in detail.

Uptake of muramyl dipeptide fluorescent congeners by normal rabbit bronchoalveolar lavage cells: a study using flow cytometry.

Muramyl dipeptide (MDP) is the minimal adjuvant-active structure of mycobacterial cell walls and is known to activate monocytes/macrophages, but mechanisms involved with uptake and activation of these cells have not been completely defined. Earlier studies addressing uptake of MDP and the question of receptors have utilized radioligands and murine peritoneal macrophages. We used fluorescent congeners of MDP and flow cytometry to explore kinetics and specificity of uptake by bronchoalveolar cells of normal rabbits. Both washed cells and cell suspensions from which the fluorescent congeners were not washed were used, and incubation was carried out primarily at 4 degrees C. Fluorescence microscopy consistently revealed intracellular but no visible membrane fluorescence of alveolar macrophages. Uptake was dose dependent but was not saturable up to concentration limits of fluoresceinated muramyl tripeptide (MTP-FITC) imposed by the system, and was partially inhibited by excess unlabeled MDP, consistent with specific inhibition. Alveolar macrophages, but not lymphocytes, demonstrated specific uptake at 4 degrees C, with rapid on- and off-times. Uptake was enhanced 7-fold at 37 degrees C. Uptake was greater by larger, more granular macrophages than by smaller, less granular macrophages, but no difference in uptake was found when cells of similar size but different densities were compared. The exact mechanism of the rapid uptake at 4 degrees C is uncertain but appears to be competed for by unlabeled MDP.

Comparing nutrition programs conducted by public health and Cooperative Extension personnel.

We surveyed 218 county extension agents, 75 state extension specialists, 163 public health nutritionists, and 87 public health administrators in 16 states to compare the nutrition program characteristics of extension personnel with public health personnel. Public health personnel were most strongly influenced by funding regulations--more than 80% of public health nutritionists cited infant/preschool nutrition and nutrition for pregnant/lactating women as program topics. About half of the extension agents listed food preservation and preparation as the dominant topics provided. Public health personnel most frequently designed programs for pregnant and lactating women and low-income clientele; 91% of the nutritionists ranked one-to-one counseling as one of their three most important delivery methods. Extension personnel designed programs more often for homemakers/adults and youth and ranked a combination of group and media delivery methods as most important. Public health personnel use anthropometric measures and food intake records to evaluate their programs; extension personnel use written questionnaires and program records. More than 50% of the nutritionists ranked improving the health of their clients as one of the three most important impacts of their programs; more than 50% of the extension agents ranked increasing knowledge and improving skills as their most important impacts.

Heme-peptide/protein interactions: the binding of heme octa and undecapeptides, and microperoxidase-8 and -11, to human serum albumin.

The interaction of the heme octa (MP-8) and undeca (MP-11) peptides derived from cytochrome c with lipidated human serum albumin (HSA) has been investigated in aqueous solution. It is demonstrated that complex formation occurs in each case with a 1:1 stoichiometry. CN- binding has been used to investigate the accessibility of the heme in each complex by comparison with CN- interaction with methemalbumin. A preliminary study of the kinetics of the Fe3+MP-8/11 human serumalbumin (HSA) interaction demonstrates a clear ligand-size-related effect on mechanism of interaction--an ad hoc explanation of which is given in terms of HSA existing as two nonconverting conformers in solution.