Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

The Chinese hamster FANCG/XRCC9 mutant NM3 fails to express the monoubiquitinated form of the FANCD2 protein, is hypersensitive to a range of DNA damaging agents and exhibits a normal level of spontaneous sister chromatid exchange

Fanconi anemia (FA) is a human autosomal disorder characterized by cancer susceptibility and cellular sensitivity to DNA crosslinking agents such as mitomycin C and diepoxybutane. Six FA genes have been cloned including a gene designated XRCC9 (for X-ray Repair Cross Complementing), isolated using a mitomycin C-hypersensitive Chinese hamster cell mutant termed UV40, and subsequently found to be identical to FANCG. A nuclear complex containing the FANCA, FANCC, FANCE, FANCF and FANCG proteins is needed for the activation of a sixth FA protein FANCD2. When monoubiquitinated, the FANCD2 protein co-localizes with the breast cancer susceptibility protein BRCA1 in DNA damage induced foci. In this study, we have assigned NM3, a nitrogen mustard-hypersensitive Chinese hamster mutant to the same genetic complementation group as UV40. NM3, like human FA cell lines (but unlike UV40) exhibits a normal spontaneous level of sister chromatid exchange. We show that both NM3 and UV40 are also hypersensitive to other DNA crosslinking agents (including diepoxybutane and chlorambucil) and to non-crosslinking DNA damaging agents (including bleomycin, streptonigrin and EMS), and that all these sensitivities are all corrected upon transfection of the human FANCG/XRCC9 cDNA. Using immunoblotting, NM3 and UV40 were found not to express the active monoubiquitinated isoform of the FANCD2 protein, although expression of the FANCD-L isoform was restored in the FANCG cDNA transformants, correlating with the correction of mutagen-sensitivity. These data indicate that cellular resistance to these DNA damaging agents requires FANCG and that the FA gene pathway, via its activation of FANCD2 and that protein's subsequent interaction with BRCA1, is involved in maintaining genomic stability in response not only to DNA interstrand crosslinks but also a range of other DNA damages including DNA strand breaks. NM3 and other "FA-like" Chinese hamster mutants should provide an important resource for the study of these processes in mammalian cells.

New molecular phenotypes in the dst mutants of Arabidopsis revealed by DNA microarray analysis

In this study, DNA microarray analysis was used to expand our understanding of the dst1 mutant of Arabidopsis. The dst (downstream) mutants were isolated originally as specifically increasing the steady state level and the half-life of DST-containing transcripts. As such, txhey offer a unique opportunity to study rapid sequence-specific mRNA decay pathways in eukaryotes. These mutants show a threefold to fourfold increase in mRNA abundance for two transgenes and an endogenous gene, all containing DST elements, when examined by RNA gel blot analysis; however, they show no visible aberrant phenotype. Here, we use DNA microarrays to identify genes with altered expression levels in dst1 compared with the parental plants. In addition to verifying the increase in the transgene mRNA levels, which were used to isolate these mutants, we were able to identify new genes with altered mRNA abundance in dst1. RNA gel blot analysis confirmed the microarray data for all genes tested and also was used to catalog the first molecular differences in gene expression between the dst1 and dst2 mutants. These differences revealed previously unknown molecular phenotypes for the dst mutants that will be helpful in future analyses. Cluster analysis of genes altered in dst1 revealed new coexpression patterns that prompt new hypotheses regarding the nature of the dst1 mutation and a possible role of the DST-mediated mRNA decay pathway in plants.

New molecular phenotypes in the dst mutants of Arabidopsis revealed by DNA microarray analysis

In this study, DNA microarray analysis was used to expand our understanding of the dst1 mutant of Arabidopsis. The dst (downstream) mutants were isolated originally as specifically increasing the steady state level and the half-life of DST-containing transcripts. As such, txhey offer a unique opportunity to study rapid sequence-specific mRNA decay pathways in eukaryotes. These mutants show a threefold to fourfold increase in mRNA abundance for two transgenes and an endogenous gene, all containing DST elements, when examined by RNA gel blot analysis; however, they show no visible aberrant phenotype. Here, we use DNA microarrays to identify genes with altered expression levels in dst1 compared with the parental plants. In addition to verifying the increase in the transgene mRNA levels, which were used to isolate these mutants, we were able to identify new genes with altered mRNA abundance in dst1. RNA gel blot analysis confirmed the microarray data for all genes tested and also was used to catalog the first molecular differences in gene expression between the dst1 and dst2 mutants. These differences revealed previously unknown molecular phenotypes for the dst mutants that will be helpful in future analyses. Cluster analysis of genes altered in dst1 revealed new coexpression patterns that prompt new hypotheses regarding the nature of the dst1 mutation and a possible role of the DST-mediated mRNA decay pathway in plants.

Mitochondrial abnormalities in ageing macular photoreceptors

PURPOSE

To evaluate somatic mitochondrial (mt)DNA mutations in the macula during ageing.

METHODS

Ten 30-microm cryostat sections from the macula (foveal and perifoveal regions) and peripheral retina of 14 donors (aged 14-94 years) were cut for cytochrome c oxidase cytochemistry. The photoreceptor layer was microdissected and DNA extracted for 4977-bp mtDNA (mtDNA(4977)) quantification using PCR. Dual cytochemistry for cytochrome c oxidase and succinate dehydrogenase allowed the detection of cytochrome c oxidase-deficient cones.

RESULTS

Findings showed a progressive accumulation of mtDNA(4977) from ages 14 to 94 years. From ages 14 to 60 years there was an increase from 0.006% to 0.25%, and from ages 60 to 94 years there was a steeper increase from 0.25% to 5.39%. Counts of cones in the dual-reacted preparations showed more cytochrome c oxidase-deficient cones in the foveal region than elsewhere.

CONCLUSIONS

The results show that mitochondrial DNA deletions and cytochrome c oxidase-deficient cones accumulate in the ageing retina, particularly in the foveal region. These defects may contribute to the changes in macular function observed in ageing and age-related maculopathy.

Accelerated s-nitrosothiol breakdown by amyotrophic lateral sclerosis mutant copper,zinc-superoxide dismutase

Mutations in copper,zinc-superoxide dismutase (SOD) have been implicated in familial amyotrophic lateral sclerosis (FALS). We have investigated the breakdown of S-nitrosothiols by wild-type (WT) SOD and two common FALS mutants, alanine-4 valine (A4V) SOD and glycine-37 arginine (G37R) SOD. In the presence of glutathione, A4V SOD and G37R SOD catalyzed S-nitrosoglutathione breakdown three times more efficiently than WT SOD. Indeed, A4V SOD catabolized GSNO more efficiently than WT SOD throughout the physiological range of GSH concentrations. Moreover, a variety of additional S-nitrosothiols were catabolized more readily by A4V SOD than by WT SOD. Initial rate data for fully reduced WT SOD and A4V SOD, and data using ascorbic acid as the reductant, suggest that FALS mutations in SOD may influence the efficiency of reduction of the copper center by glutathione. We have identified a potentially toxic gain of function of two common FALS mutations that may contribute to neurodegeneration in FALS.

Thalidomide is distributed into human semen after oral dosing

As part of a double-blind placebo-controlled study of the effect of thalidomide on body weight and the viral load of human immunodeficiency virus-seropositive patients, plasma and semen samples were analyzed for the presence of thalidomide. Patients were orally dosed with 100 mg of thalidomide/day for 8 weeks. Blood samples were obtained at baseline and weeks 4, 8, and 12, and semen was obtained at baseline and weeks 4 and 8. Samples were extracted with solid-phase cartridges and analyzed by liquid chromatography/tandem mass spectrometry using atmospheric pressure chemical ionization in the negative ion mode. Two of four patients taking thalidomide were able to provide semen samples. Both had detectable levels of thalidomide in their plasma (10-350 ng/ml) and semen (10-250 ng/g) at weeks 4 and 8. There was an apparent correlation between plasma and semen levels. Semen levels could be significantly greater for therapeutic doses of more than 100 mg/day. Since the threshold dose for birth defects and thalidomide exposure is not known, male patients are advised to use barrier contraception.

Replicative fitness in vivo of HIV-1 variants with multiple drug resistance-associated mutations

The relative fitness of HIV-1 viral variants containing a broad range of drug resistance-associated mutations has been little studied in vivo. Understanding the relative fitness associated with viruses containing mutations may aid future therapeutic management. The aim of this study was to investigate the relative fitness of mutant viruses by assessing a cohort of patients who had developed resistance to many drugs and subsequently stopped all therapy. Eleven patients were assessed for drug resistance associated mutations in the protease (PR) and reverse transcriptase (RT) genes before and, at multiple time points, after stopping therapy. Relative fitness was calculated as a function of the rate of disappearance of mutant viruses when therapy was stopped. The least fit viruses were associated with the RT mutation M184I/V (11.6% less fit) and the PR mutations D30N (12.4% less fit) and M46I/L (21% less fit). Mutations at these codons were associated with significant reductions in fitness levels compared to wild-type viruses. Mutations at codons 10, 20, 36, and 63 in the PR gene remained fairly constant when therapy was stopped and may not significantly reduce viral fitness. The rapid re-population of wild-type viruses may allow the recycling of antiretroviral drugs prescribed previously.

S-nitrosothiols signal the ventilatory response to hypoxia

Increased ventilation in response to hypoxia has been appreciated for over a century, but the biochemistry underlying this response remains poorly understood. Here we define a pathway in which increased minute ventilation (&Vdot;E ) is signalled by deoxyhaemoglobin-derived S-nitrosothiols (SNOs). Specifically, we demonstrate that S-nitrosocysteinyl glycine (CGSNO) and S-nitroso-l-cysteine (l-CSNO)-but not S-nitroso-d-cysteine (d-CSNO)-reproduce the ventilatory effects of hypoxia at the level of the nucleus tractus solitarius (NTS). We show that plasma from deoxygenated, but not from oxygenated, blood produces the ventilatory effect of both SNOs and hypoxia. Further, this activity is mediated by S-nitrosoglutathione (GSNO), and GSNO activation by gamma-glutamyl transpeptidase (gamma-GT) is required. The normal response to hypoxia is impaired in a knockout mouse lacking gamma-GT. These observations suggest that S-nitrosothiol biochemistry is of central importance to the regulation of breathing.

Reduced bone mineral density in HIV-positive individuals

A total of 105 HIV-positive patients underwent dual-energy X-ray absorbtiometry (DEXA) scan to assess bone mineral density (BMD). The prevalence of reduced BMD was found to be 71% and was higher in patients who had ever been treated with protease inhibitors (PI). Our results suggest a possible association between PI and reduced BMD, and further complicate the debate regarding when to commence treatment of HIV and with what agents to start.

A novel pantothenate kinase gene (PANK2) is defective in Hallervorden-Spatz syndrome

Hallervorden-Spatz syndrome (HSS) is an autosomal recessive neurodegenerative disorder associated with iron accumulation in the brain. Clinical features include extrapyramidal dysfunction, onset in childhood, and a relentlessly progressive course. Histologic study reveals iron deposits in the basal ganglia. In this respect, HSS may serve as a model for complex neurodegenerative diseases, such as Parkinson disease, Alzheimer disease, Huntington disease and human immunodeficiency virus (HIV) encephalopathy, in which pathologic accumulation of iron in the brain is also observed. Thus, understanding the biochemical defect in HSS may provide key insights into the regulation of iron metabolism and its perturbation in this and other neurodegenerative diseases. Here we show that HSS is caused by a defect in a novel pantothenate kinase gene and propose a mechanism for oxidative stress in the pathophysiology of the disease.

AKT-1, -2, and -3 are expressed in both normal and tumor tissues of the lung, breast, prostate, and colon

PURPOSE

The AKT/PKB kinase controls many of the intracellular processes that are dysregulated in human cancer, including the suppression of apoptosis and anoikis and the induction of cell cycle progression. Three isoforms of AKT have been identified: AKT-1, -2, and -3. Selective up-regulation of AKT-3 RNA expression has been reported in hormone-independent breast and prostate cancer cell lines suggesting that AKT-3 expression may be increased with breast or prostate tumor progression. To determine whether AKT-3 RNA expression is selectively up-regulated in human cancers and whether the patterns of AKT RNA expression may change with tumor development, we examined AKT isoform expression by RT-PCR in human cancer cell lines, primary human cancers, and normal human tissues.

EXPERIMENTAL DESIGN

AKT-1, -2, and -3 RNA expression was examined by RT-PCR. Because up-regulated AKT-3 expression has been implicated in human breast and prostate cancer progression, we also examined AKT-3 expression levels by semiquantitative RT-PCR using matched normal/tumor first-strand cDNA pairs from colon, breast, prostate, and lung cancers.

RESULTS

Our data reveal that the overwhelming majority of both normal and tumor tissues express all three of the AKT isoforms. Moreover, semiquantitative RT-PCR of matched normal/tumor pairs confirmed similar AKT-3 RNA expression levels in both normal and tumor tissue.

CONCLUSIONS

Our data show that both normal and tumor tissues express all three of the AKT isoforms and indicate that tumorigenesis does not involve a dramatic shift in the RNA expression patterns of the three AKT isoforms.

Mitochondrial enzyme-deficient hippocampal neurons and choroidal cells in AD

OBJECTIVE

To determine whether hippocampal neurons and choroidal epithelial cells demonstrate a mitochondrial enzyme deficiency in AD more frequently than in normal aging.

BACKGROUND

High levels of mutant mitochondrial DNA (mtDNA) cause a deficiency in cytochrome c oxidase (COX) (complex IV activity) because three of its 13 subunits are encoded for by mtDNA. In contrast, succinate dehydrogenase (SDH) (complex II activity) remains intact because all of its subunits are nuclear encoded. The histologic hallmark of cells containing high levels of mtDNA mutation in both primary mtDNA disorders and normal aging muscle is the presence of COX-deficient SDH-positive cells.

METHODS

The authors applied a sequential histochemical method for COX and SDH to hippocampal sections in 17 AD and 17 age-matched control brains. This confers the advantages of both looking at individual cells in situ and measuring the actual mitochondrial complex activity rather than simply the complex quantity.

RESULTS

COX-deficient SDH-positive hippocampal neurons and choroidal epithelial cells are more prevalent in patients with AD than in controls. In addition the COX-deficient SDH-positive choroidal cells are associated with an enlargement in size.

CONCLUSION

This increase in number of COX-deficient SDH-positive hippocampal pyramidal neurons and choroid epithelial cells provides strong evidence that a substantial mitochondrial enzyme activity defect occurs in individual cells more frequently in AD than in normal aging and that mitochondria may play a significant role in the pathogenesis of AD.

Mitochondrial DNA mutations in disease and ageing

The chronological accumulation of mitochondrial DNA mutations has been proposed as a potential mechanism in the physiological processes of ageing and age-related disease. We discuss the evidence behind this theory and relate some of the ageing mitochondrial changes to mitochondrial DNA disorders. In particular, we describe the aggregation of cytochrome c oxidase-deficient cells in both skeletal muscle and the CNS in normal ageing as seen in the mitochondrial DNA disorders. These mitochondrial enzyme-deficient cells have been shown to occur in significant quantities in both muscle and CNS in patients with mitochondrial DNA disorders. In both ageing and mtDNA disorder muscle these cytochrome c-deficient fibres contain high levels of a single mutant strain of mitochondrial DNA. Whether these mutations are a primary or secondary event in the physiology of ageing remains to be determined.

Pharmacokinetics of zidovudine and lamivudine in neonates following coadministration of oral doses every 12 hours

A phase I, repeat-dose, open-label study was conducted to determine the pharmacokinetics and safety of zidovudine and lamivudine, coadministered orally every 12 hours, in 16 neonates whose mothers were infected with human immunodeficiency virus type 1 (HIV-1). The prospective mothers had been stabilized on a zidovudine/lamivudine regimen since week 36 of pregnancy to prevent mother-to-child transmission of HIV. During 1 week postpartum, the mothers received zidovudine 300 mg plus lamivudine 150 mg every 12 hours and breastfed. Neonatal treatment was initiated 12 hours following birth with 4 mg/kg of zidovudine suspension plus 2 mg/kg of lamivudine solution every 12 hours; this regimen was continued for 1 week. Between days 1 and 7 of neonatal treatment, the neonatal oral clearance (CL/F) of zidovudine and lamivudine increased by 2-fold (p < 0.001) and 1.6-fold (p = 0.004), respectively, possibly reflecting maturation of intestinal hepatic and renal function occurring during the first week of life. Day 7/day 1 ratios for exposure (area under the serum concentration-time curve [AUC]) and maximum observed serum concentration (Cmax) were 0.48 and 0.63, respectively, for zidovudine and 0.64 and 0.73, respectively, for lamivudine. At the time of delivery, the geometric mean cord/maternal concentration ratio was 1.24 for zidovudine and 1.12 for lamivudine, indicating free passage of each drug across the placenta. The maternal and neonatal treatment regimens were well tolerated. The results of this study confirm that in the neonate, a convenient regimen combining zidovudine 4 mg/kg and lamivudine 2 mg/kg, administered orally every 12 hours, provides zidovudine serum exposure very similar to that reported with the standard neonatal zidovudine regimen of 2 mg/kg every 6 hours, as well as lamivudine serum exposure within the range reported in adults receiving lamivudine 150 mg twice a day and children receiving 4 mg/kg twice a day.

Immunity in the female lower genital tract and the impact of HIV infection

This study investigates the distribution of immunocompetent cells in the ectocervix, and cytokine and immunoglobulin (Ig) levels in cervicovaginal secretions to determine whether they are altered in asymptomatic human immunodeficiency virus (HIV) infection. Ectocervical biopsies from 10 HIV+ and 10 presumed HIV-ve women were studied by immunocytochemistry. Levels of Igs in cervicovaginal secretions were quantified by radial immunodiffusion (RID) and cytokine levels by ELISA. HIV+ women had significantly increased numbers of CD8+ lymphocytes resulting in reversal of the CD4:CD8 ratio. There was a significant increase in the proportion of activated CD8+ HLA-DR+ and CD4+ HLA-DR + lymphocytes, but not in CD8+ TIA-1+ cells. The epithelium of the cervix from HIV+ subjects showed a significant increase in both numbers of macrophages (CD68+) and proportions of activated macrophages (CD68+ HLA-DR+) compared to normal. The stroma contained increased proportions of inductive (D1+) and suppressive (D1+ D7+) macrophages but a decrease in effector phagocyte (D7+) proportions and Langerhans' cells. Significantly lower tumour necrosis factor (TNF)-alpha levels were observed in cervicovaginal secretions from HIV+ subjects. IgG levels were 4 times higher and IgM levels twice higher in cervicovaginal secretions from HIV+ women, compared to results from normal subjects. These results suggest a response within the CD8+ cells in HIV+ women, yet these cells may have a low cytolytic capacity. The raised proportions of HLA-DR+ and D1+ CD4+ macrophages could act as antigen-presenting cells (APC) for CD4+ CD45RO+ lymphocytes, and represent a local acquired response. However, the close juxtaposition of these cells offers the potential for them to act as a local reservoir of virus and promote its proliferation. The increase of IgG over sIgA in secretions of HIV+ subjects provides evidence suggesting a dysregulation of local humoral immunity.

Vaccination of pigs with a recombinant porcine adenovirus expressing the gD gene from pseudorabies virus

Five week old, commercially available large white pigs were vaccinated with either a single dose or two doses of a recombinant porcine adenovirus expressing the glycoprotein D gene from pseudorabies virus (PRV). Pigs were monitored for the development of serum neutralizing antibodies to PRV and challenged 3 weeks after final vaccination. Prior to challenge, pigs given 2 doses of the vaccine demonstrated boosted levels of antibody compared with those given a single dose, and all surviving pigs had increased neutralization titres over pre-challenge levels. Following challenge, pigs were monitored for clinical signs of disease, with blood and nasal swabs collected for virus isolation. All control animals became sick with elevated temperatures for 6 days post challenge, whereas; vaccinated animals displayed an increase in body temperature for only 2-3 days. Control pigs and those given a single dose all lost condition, but the group given 2 doses remained healthy. At postmortem, gross lesions of pneumonia only occurred in control animals and those given a single dose of vaccine. Histology carried out on the brains of all animals demonstrated a difference in severity of infection and frequency of immunohistochemical antigen detection between test animals, with control and single dose groups being most severely affected and pigs given 2 doses the least. Virus isolation studies demonstrated that no viraemia could be detected, but virus was found in nasal swabs from some animals in both groups of vaccinates following challenge.

Accelerated ageing changes in the choroid plexus of a case with multiple mitochondrial DNA deletions

Mitochondrial abnormalities, in particular the accumulation of mitochondrial DNA mutations, have been proposed as a potential cause of normal ageing. One group of patients with mtDNA disorders have a nuclear DNA defect which accelerates the chronological accumulation of mitochondrial DNA mutations. These patients provide an ideal means of investigating whether accelerated mitochondrial DNA defects can cause accelerated ageing pathology. The choroid plexus demonstrates a robust accumulation of pathological changes, in the form of Biondi bodies, with normal ageing. We have therefore examined the choroid plexus of a case with multiple mitochondrial DNA deletions for evidence of accelerated ageing and compared it with two cases with point mutation mitochondrial DNA disorders and several age-matched and elderly controls with and without clinical and neuropathological evidence of neurodegenerative disease. We also demonstrate that the choroid plexus of the mitochondrial DNA cases contain cells with levels of mitochondrial DNA mutation sufficient to cause a biochemical deficiency in the oxidative phosphorylation pathway. As previously reported, both cases with point mutation mitochondrial DNA disorders exhibit a characteristic oncocytic type transformation of the choroidal epithelial cells. However, in the case with multiple mitochondrial DNA deletions we demonstrate pathological changes in choroid plexus that are strongly suggestive of accelerated ageing. We believe that this finding supports the theory that the accumulation of mitochondrial DNA mutations can lead to pathological changes typical of ageing cells.

Washout periods for brimonidine 0.2% and latanoprost 0.005%

PURPOSE

To evaluate the intraocular pressure washout time after discontinuing brimonidine 0.2% twice daily and latanoprost 0.005% once every evening.

METHODS

We discontinued brimonidine or latanoprost in a masked fashion from primary open-angle glaucoma or ocular hypertensive patients. The intraocular pressure was measured twice weekly until patients returned to untreated baseline.

RESULTS

In 32 patients, the mean longest eye washout time for brimonidine (n = 15) was 3.3 +/- 3.0 weeks and for latanoprost (n = 17) was 4.4 +/- 3.2 weeks (P =.24). In all but one patient, brimonidine returned to baseline by 5 weeks and latanoprost returned by 8 weeks.

CONCLUSION

After discontinuing latanoprost or brimonidine, a wide variation exists in washout times among individuals, with latanoprost demonstrating a trend to a longer washout period.

A prime-boost vaccination strategy using naked DNA followed by recombinant porcine adenovirus protects pigs from classical swine fever

Weaned pigs (6-week-old) and 7-day-old pre-weaned piglets were vaccinated with naked plasmid DNA expressing the gp55/E2 gene from classical swine fever virus (CSFV). Both groups of pigs were then given a booster dose of recombinant porcine adenovirus expressing the gp55 gene (rPAV-gp55). Following challenge with CSFV, 100% of weaned pigs and 75% pre-weaned piglets were protected from disease. Weaned pigs given a single dose of rPAV-gp55 were also protected, but showed a slight increase in temperature immediately post-challenge. However, weaned animals given a DNA prime before rPAV-gp55 showed no fluctuation in body temperature following challenge and no pathology in spleen or lymph nodes upon post-mortem. In addition, no CSFV could be re-isolated from the rPAV vaccinated group and from only one pig in the prime-boost group following challenge, suggesting that both vaccination regimes have the potential to reduce or prevent virus shedding following experimental challenge.

Pichia pastoris Pex14p, a phosphorylated peroxisomal membrane protein, is part of a PTS-receptor docking complex and interacts with many peroxins

The peroxisomal protein import machinery plays a central role in the assembly of this organelle in all eukaryotes. Genes encoding components of this machinery, termed peroxins or Pex proteins, have been isolated and characterized in several yeast species and in mammals, including humans. Here we report on one of these components, Pex14p, from the methylotrophic yeast Pichia pastoris. Work in other organisms has shown that Pex14p is located on the cytoplasmic surface of the peroxisomal membrane and binds peroxisomal targeting signal (PTS) receptors carrying proteins bound for the peroxisomal matrix, results that have led to the hypothesis that Pex14p is a receptor-docking protein. P. pastoris Pex14p (PpPex14p) behaves like an integral membrane protein, with its C-terminus exposed on the cytosolic side of the peroxisomal membrane. PpPex14p complexes with many peroxins, including Pex3p (Snyder et al., 1999b), Pex5p, Pex7p, Pex13p, Pex17p, itself, and a previously unreported peroxin, Pex8p. A portion of Pex14p is phosphorylated, but both phosphorylated and unphosphorylated forms of Pex14p interact with several peroxins. The interactions between Pex14p and other peroxins provide clues regarding the function of Pex14p in peroxisomal protein import.

High calcium intake blunts pregnancy-induced increases in maternal blood lead

In pregnant women with low exposure to lead, high intakes of calcium (>2,000 mg/day) decreased the serum concentration of lead, which could potentially minimize fetal exposure to lead. This is twice the amount of calcium recommended for women during pregnancy and approaches the Upper Level for calcium of 2,500 mg/day. The mechanism by which high calcium intake blunts pregnancy-induced increases in maternal blood lead may involve decreased lead absorption in the intestine or decreased maternal bone resorption with subsequent release of lead. Either mechanism could decrease maternal blood concentrations of lead and potentially limit fetal accumulation of lead.

Radiotherapeutic efficacy of (153)Sm-CMDTPA-Tyr(3)-octreotate in tumor-bearing rats

A number of radiolabeled somatostatin analogs have been evaluated in animal tumor models for radiotherapeutic efficacy. The majority of the agents tested have used either high-energy beta-emitters, such as Y-90 or Re-188, or the Auger electron-emitting radionuclide, In-111. Because a medium-energy beta-emitter might have equivalent efficacy compared to high-energy emitters, and lower toxicity to non-target tissues, we have evaluated the therapeutic potential of the beta-emitting nuclide, Sm-153, chelated to the somatostatin analog, CMDTPA-Tyr(3)-octreotate. Using an in vitro binding assay, this octreotate derivative was shown to have high affinity for the somatostatin subtype-2 receptor (IC(50) = 2.7 nM). Biodistribution studies in CA20948 tumor-bearing Lewis rats demonstrate that the Sm-153 labeled compound has high uptake and retention in tumor tissue (1.7% injected dose/g tissue, 4 hrs post injection) and has rapid overall clearance properties from non-target tissue. Radiotherapy studies were carried out using (153)Sm-CMDTPA-Tyr(3)-octreotate and CA20948 tumor bearing Lewis rats at 7 days post implant. Dose regimens consisting of single and multiple i.v. injections of 5.0 mCi/rat (185 MBq) were employed over a time span of 7 days. Suppression of tumor growth rate was observed in all treated animals compared to untreated controls. Greater inhibition of tumor growth was observed in animals that received multiple doses. These studies indicate that medium-energy beta-emitting isotopes have considerable potential for the treatment of somatostatin receptor-positive tumors.