The use of feathers in monitoring bioaccumulation of metals and metalloids in the South African endangered African grass-owl (Tyto capensis).

Few studies have quantified metals in South African species and no published data on residues specifically in South African owl feathers exist. Tyto capensis is listed as vulnerable within South Africa, making it preferable to use a non-invasive technique to determine metal bioaccumulation for this species. Comparisons are made with the cosmopolitan T. alba to determine whether this species could be used as a surrogate. Concentrations of various metals were thus determined in feathers of the two species and compared with liver and muscle samples. Samples were taken from 119 owls collected as road kill along a national road. A comparison of concentrations in feathers revealed similarly higher concentrations of aluminium, antimony, lead, nickel, and strontium, whereas concentrations of chromium, copper, iron, manganese, selenium, titanium and zinc were similarly higher in internal tissues for both species. Metal concentrations of owls were comparable to those reported in literature and below toxic levels, suggesting that these metals were not likely to impact the owls. Further regressions between feathers and corresponding livers were examined to determine if feathers were indicative of internal metal burdens. Significant positive relationships were found for aluminium, copper, lead, nickel and vanadium in T. alba and nickel, manganese and vanadium in T. capensis. Preliminary results support the feasibility of using feathers as non-destructive indicators of environmental contamination in T. capensis although caution needs to be taken when interpreting the results.

Virus-like particles for antigen delivery at mucosal surfaces.

Virus-like particles are a new type of vaccine platform that presents an attractive alternative to more traditional live-attenuated or inactivated/subunit vaccines. Virus-like particles (VLP) are composed of viral structural proteins that assemble spontaneously in cells, mimicking the live virus without the possibility of replication. They are readily recognized by the immune system, inducing both humoral and cellular immune responses. Here we review the development of VLP as vaccine delivery systems at mucosal surfaces. We first summarize the current status of VLP vaccines in general, and then discuss their use in mucosal vaccination approaches for several viruses that enter the host via the urogenital, respiratory or gastrointestinal tract.

Delivery of interferon-beta to the monkey nervous system following intranasal administration.

We determined the nervous system targeting of interferon-beta1b (IFN-beta1b), a 20 kDa protein used to treat the relapsing-remitting form of multiple sclerosis, following intranasal administration in anesthetized, adult cynomolgus monkeys. Five animals received an intranasal bolus of [(125)I]-labeled IFN-beta1b, applied bilaterally to the upper nasal passages. Serial blood samples were collected for 45 min, after which the animals were euthanized by transcardial perfusion-fixation. High resolution phosphor imaging of tissue sections and gamma counting of microdissected tissue were used to obtain the distribution and concentration profiles of [(125)I]-IFN-beta1b in central and peripheral tissues. Intranasal administration resulted in rapid, widespread targeting of nervous tissue. The olfactory bulbs and trigeminal nerve exhibited [(125)I]-IFN-beta1b levels significantly greater than in peripheral organs and at least one order of magnitude higher than any other nervous tissue area sampled. The basal ganglia exhibited highest [(125)I]-IFN-beta1b levels among CNS regions other than the olfactory bulbs. Preferential IFN-beta1b distribution to the primate basal ganglia is a new finding of possible clinical importance. Our study suggests both IFN-beta and IFN-alpha, which share the same receptor, may be bound with relatively high affinity in these structures, possibly offering new insight into a neurovegetative syndrome induced by IFN-alpha therapy and suspected to involve altered dopamine neurotransmission in the basal ganglia. Most importantly, our results suggest intranasally applied macromolecules may bypass the blood-brain barrier and rapidly enter the primate CNS along olfactory- and trigeminal-associated extracellular pathways, as shown previously in the rat. This is the first study to finely detail the central distribution of a labeled protein after intranasal administration in non-human primates.

Intranasal administration of interferon beta bypasses the blood-brain barrier to target the central nervous system and cervical lymph nodes: a non-invasive treatment strategy for multiple sclerosis.

Intranasal (i.n.) administration of IFN beta-1b was examined as a route for targeted delivery to the rat central nervous system (CNS). Intranasal administration resulted in significant delivery throughout the CNS and cervical lymph nodes with low delivery to peripheral organs. At similar blood levels, intravenous (i.v.) administration of IFN beta-1b yielded 88-98% lower CNS levels and 100-1650% greater peripheral organ levels compared to intranasal. Autoradiography confirmed much greater delivery to the CNS with intranasal administration. Intranasally administered IFN beta-1b reached the brain intact and produced tyrosine phosphorylation of IFN receptor in the CNS. Intranasal administration offers a non-invasive method of drug delivery for multiple sclerosis (MS) that bypasses the blood-brain barrier (BBB) and directly targets the CNS and lymph nodes.

C3d enhancement of neutralizing antibodies to measles hemagglutinin.

Measles remains a major cause of worldwide infant mortality despite the use of current live attenuated vaccines. New approaches to measles virus (MV) vaccine development are critical to interrupt the spread of MV. In this study, we report the results using a DNA vaccine expressing a fusion of the measles hemagglutinin (H) protein and the complement component, C3d, to enhance the titers of neutralizing antibody. Plasmids were generated that expressed a secreted (s) form of H and the same form fused to three tandem copies of the murine homologue of C3d (sH-3C3d). Analysis of titers of the antibody raised in vaccinated mice indicated that immunizations with the DNA expressing sH-3C3d had higher titers of anti-H antibodies compared to serum from mice vaccinated with DNA expressing sH only. In addition, sH-3C3d elicited higher neutralizing antibody titers that inhibited MV induced plaque formation.

Vigabatrin effect on inner retinal function.

OBJECTIVE: To determine the degree of electroretinal dysfunction in a group of patients taking Vigabatrin (VGB). Additionally, to investigate the role of cumulative dosage, the role of VGB alone or in combination with other anticonvulsants, and whether recent discontinuance of VGB affects electroretinal function as measured by the electroretinogram (ERG). DESIGN: Retrospective, comparative case series. PARTICIPANTS: Forty patients (18 male, 22 female) with a mean age of 35 years were studied as three groups: the VGB multitherapy group (n = 24) included those taking VGB with other anticonvulsants, the VGB monotherapy group (n = 9) included those taking VGB alone, and the off-VGB group (n = 7) included those who had discontinued VGB in the last 6 months. METHODS: Scotopic flash, photopic flash, and 30-Hz flicker ERG results were recorded according to the International Society for Clinical Electrophysiology of Vision (ISCEV) standard. The clinical electro-oculogram (EOG) results were recorded according to the ISCEV standard. MAIN OUTCOME MEASURES: Implicit time and amplitudes of the A- and B-waves of the flash and 30-Hz flicker ERGs were recorded. Summed amplitude of the first three oscillatory potential wavelets were recorded. The light-peak to-dark-trough Arden ratio of the EOG was evaluated. RESULTS: Although photopic ERG B-wave reduction was most frequent in patients in the VGB multitherapy group (48% of eyes), a significant number of eyes in all three groups had scotopic ERG B-wave reduction. The 30-Hz flicker ERG result was abnormally reduced in all three groups. There was no significant difference in the frequency of occurrence in ERG result abnormalities between the VGB monotherapy and VGB multitherapy groups. The EOG results revealed reduced Arden ratios in all three groups; however, there was a significantly lower frequency of EOG abnormalities noted in the off-VGB group (P = 0. 0373). There was no statistically significant relationship between the frequency of electrodiagnostic abnormalities and the duration of use or the total cumulative dosage of Vigabatrin in any of the three groups. CONCLUSIONS: These findings of scotopic ERG result abnormalities suggest that VGB alone has an effect on inner electroretinal function at the level of the Müller cell. Concomitant EOG abnormalities suggest a substantial effect of VGB on outer retinal function that may be reversible after cessation of VGB treatment.

Enhanced avidity maturation of antibody to human immunodeficiency virus envelope: DNA vaccination with gp120-C3d fusion proteins.

DNA vaccination can elicit both humoral and cellular immune responses and can confer protection against several pathogens. However, DNA vaccines expressing the envelope (Env) protein of human immunodeficiency virus (HIV) have been relatively ineffective at generating high titer, long-lasting, neutralizing antibodies in a variety of animal models. In this study, we report that fusion of Env and the complement component, C3d, in a DNA vaccine, enhances the titers of antibody to Env. Plasmids were generated that expressed a secreted form of Env (sgp120) from three isolates of HIV and these same forms fused to three tandem copies of the murine homologue of C3d (sgp120-3C3d). Analyses of titers and avidity maturation of the raised antibody indicated that immunizations with each of the sgp120-3C3d-expressing DNAs accelerated both the onset and the avidity maturation of antibody to Env.

Using death to one's advantage: HIV modulation of apoptosis.

Infection by human immunodeficiency virus (HIV) is associated with an early immune dysfunction and progressive destruction of CD4+ T lymphocytes. This progressive disappearance of T cells leads to a lack of immune control of HIV replication and to the development of immune deficiency resulting in the increased occurrence of opportunistic infections associated with acquired immune deficiency syndrome (AIDS). The HIV-induced, premature destruction of lymphocytes is associated with the continuous production of HIV viral proteins that modulate apoptotic pathways. The viral proteins, such as Tat, Env, and Nef, are associated with chronic immune activation and the continuous induction of apoptotic factors. Viral protein expression predisposes lymphocytes, particularly CD4+ T cells, CD8+ T cells, and antigen-presenting cells, to evolve into effectors of apoptosis and as a result, to lead to the destruction of healthy, non-infected T cells. Tat and Nef, along with Vpu, can also protect HIV-infected cells from apoptosis by increasing anti-apoptotic proteins and down-regulating cell surface receptors recognized by immune system cells. This review will discuss the validity of the apoptosis hypothesis in HIV disease and the potential mechanism(s) that HIV proteins perform in the progressive T cell depletion observed in AIDS pathogenesis.

2,3-Dihydro-dithiin and -dithiepine-1,1,4,4-tetroxides: small molecule non-peptide antagonists of the human galanin hGAL-1 receptor.

The neuropeptide galanin modulates several physiological functions such as cognition, learning, feeding behavior, and depression, probably via the galanin 1 receptor (GAL-R1). Using an HTS assay based on 125I-human galanin binding to the human galanin-1 receptor (hGAL-R1), we discovered a series of 1,4-dithiin and dithiipine-1,1,4,4-tetroxides that exhibited binding affinity IC50's to hGAL-R1 ranging from 190 to 2700 nM. Two of the dithiepin analogues, 7 and 23, behaved pharmacologically as hGAL-R1 antagonists in secondary assays involving adenylate cyclase activity and GTP binding to G-proteins. Analogues 7 and 23 were also active in functional assays involving galanin, reversing the inhibitory effect of galanin on acetylcholine (ACh) release in rat brain hippocampal slices and electrically-stimulated guinea pig ileum twitch.

Human T-cell leukemia virus type 2 tax mutants that selectively abrogate NFkappaB or CREB/ATF activation fail to transform primary human T cells.

Human T-cell leukemia virus (HTLV) Tax protein has been implicated in the HTLV oncogenic process, primarily due to its pleiotropic effects on cellular genes involved in growth regulation and cell cycle control. To date, several approaches attempting to correlate Tax activation of the CREB/activating transcription factor (ATF) or NFkappaB/Rel transcriptional activation pathway to cellular transformation have yielded conflicting results. In this study, we use a unique HTLV-2 provirus (HTLV(c-enh)) that replicates by a Tax-independent mechanism to directly assess the role of Tax transactivation in HTLV-mediated T-lymphocyte transformation. A panel of well-characterized tax-2 mutations is utilized to correlate the respective roles of the CREB/ATF or NFkappaB/Rel signaling pathway. Our results demonstrate that viruses expressing tax-2 mutations that selectively abrogate NFkappaB/Rel or CREB/ATF activation display distinct phenotypes but ultimately fail to transform primary human T lymphocytes. One conclusion consistent with our results is that the activation of NFkappaB/Rel provides a critical proliferative signal early in the cellular transformation process, whereas CREB/ATF activation is required to promote the fully transformed state. However, complete understanding will require correlation of Tax domains important in cellular transformation to those Tax domains important in the modulation of gene transcription, cell cycle control, induction of DNA damage, and other undefined activities.

C3d enhancement of antibodies to hemagglutinin accelerates protection against influenza virus challenge.

The ability of the C3d component of complement to enhance antibody responses and protective immunity to influenza virus challenges was evaluated using a DNA vaccine encoding a C3d fusion of the hemagglutinin (HA) from influenza virus. Plasmids were generated that encoded a transmembrane HA (tmHA), a secreted form of HA (sHA), or a sHA fused to three tandem copies of the murine homologue of the C3d (sHA-3C3d). Analysis of the titers, avidity maturation, and hemagglutinin-inhibition activity of raised antibody revealed that immunizations with sHA-3C3d DNA accelerated both the avidity maturation of antibody to HA and the appearance of hemagglutinin-inhibition activity. These accelerated antibody responses correlated to a more rapid appearance of protective immunity. They also correlated to complete protection from live virus challenge by a single vaccination at a dose ten times lower than the protective dose for non-C3d forms of HA.

Inhibition of HIV-1 progeny virion release by cell-surface CD4 is relieved by expression of the viral Nef protein.

BACKGROUND: The human immunodeficiency virus type 1 (HIV-1) Nef protein is required for efficient virus replication in vivo and displays a number of distinct and apparently unrelated biological activities in vitro. Of these, one of the most readily demonstrated is the efficient internalization and degradation of cell-surface CD4, the receptor for the HIV-1 envelope protein. The biological purpose of this internalization has, however, remained unclear. RESULTS: Using human 293T cells expressing high levels of cell-surface CD4 or CD8, we demonstrate that CD4, but not CD8, can dramatically reduce the release of infectious virions bearing the HIV-1 envelope protein and induce a concomitant increase in the accumulation of cell-associated HIV-1 structural proteins. In contrast, CD4 had no effect on the release of HIV-1 bearing a heterologous envelope protein unable to bind CD4. Nef expression totally reversed CD4-mediated inhibition but only if the CD4 used remained susceptible to Nef-induced internalization. CONCLUSIONS: These results support the hypothesis that cell-surface CD4 can interact with the envelope protein present on budding HIV-1 virions to inhibit their release. The internalization and degradation of cell-surface CD4 induced by the viral Nef protein can fully reverse this inhibition and is, therefore, likely to facilitate the spread of virus in vivo.

Assessment of treatment for patients with primary ductal carcinoma in situ in the breast.

BACKGROUND: Current mammographic technology has resulted in increased detection of ductal carcinoma in situ (DCIS). It is necessary to assess which patients presenting with DCIS are good candidates for breast conservation and which of these patients should receive adjuvant radiation. METHODS: We accrued clinical data for 124 patients with a primary diagnosis of DCIS from 1979 through 1994. Primary therapy was a mastectomy for 18 patients, and a lumpectomy for 106 patients. Only 18 of the latter group of patients received adjuvant radiotherapy. For the 88 lumpectomy-alone patients (median follow-up, 5.2 years), we evaluated the effects of clinical (age and initial presentation) and pathologic (nuclear grade, architecture, parenchymal involvement, calcifications, and measured margins) factors on recurrence of DCIS or the development of invasive breast cancer. RESULTS: Patients who underwent lumpectomy with or without adjuvant radiotherapy (median follow-up, 5.0 years) were significantly more likely to have recurrence of DCIS (P=.05) than those who underwent mastectomy (median follow-up, 6.7 years): 18% (19/106) versus 0% (0/18), respectively; lumpectomy-alone patients experienced a 19% (17/88) rate of DCIS recurrence. All recurrent DCIS was ipsilateral. For lumpectomy-alone patients, the factors associated with ipsilateral recurrence of DCIS were extent of involvement of the parenchyma (P=.01, for univariate; P=.07, for multivariate) and initial presentation (P=.05, for univariate; P=.07, for multivariate). Eleven lumpectomy-alone patients developed invasive breast cancer (6 ipsilateral, 5 contralateral); none of the 18 lumpectomy patients who received adjuvant radiation developed invasive disease. None of the factors investigated, including primary surgery and adjuvant radiotherapy, were associated with a significant effect on the development of invasive disease. CONCLUSIONS: Longer follow-up is required to determine if the benefits of either mastectomy or radiotherapy following lumpectomy persist. There is a suggestion that patients under 40 years of age or women who present with nipple discharge might be considered for either adjuvant radiotherapy following lumpectomy or a simple mastectomy.

Inhibition of human immunodeficiency virus Rev and human T-cell leukemia virus Rex function, but not Mason-Pfizer monkey virus constitutive transport element activity, by a mutant human nucleoporin targeted to Crm1.

The hypothesis that the cellular protein Crm1 mediates human immunodeficiency virus type 1 (HIV-1) Rev-dependent nuclear export posits that Crm1 can directly interact both with the Rev nuclear export signal (NES) and with cellular nucleoporins. Here, we demonstrate that Crm1 is indeed able to interact with active but not defective forms of the HIV-1 Rev NES and of NESs found in other retroviral nuclear export factors. In addition, we demonstrate that Crm1 can bind the Rev NES when Rev is assembled onto the Rev response element RNA target and that Crm1, like Rev, is a nucleocytoplasmic shuttle protein. Crm1 also specifically binds the Rev NES in vitro, although this latter interaction is detectable only in the presence of added Ran . GTP. Overexpression of a truncated, defective form of the nucleoporin Nup214/CAN, termed DeltaCAN, that retains Crm1 binding ability resulted in the effective inhibition of HIV-1 Rev or human T-cell leukemia virus Rex-dependent gene expression. In contrast, DeltaCAN had no significant affect on Mason-Pfizer monkey virus constitutive transport element (MPMV CTE)-dependent nuclear RNA export or on the expression of RNAs dependent on the cellular mRNA export pathway. As a result, DeltaCAN specifically blocked late, but not early, HIV-1 gene expression in HIV-1-infected cells. These data strongly validate Crm1 as a cellular cofactor for HIV-1 Rev and demonstrate that the MPMV CTE nuclear RNA export pathway uses a distinct, Crm1-independent mechanism. In addition, these data identify a novel and highly potent inhibitor of leucine-rich NES-dependent nuclear export.

Bowel resection for intestinal endometriosis.

PURPOSE: The study contained herein was undertaken to evaluate which factors predict a good outcome following intestinal resection for endometriosis. METHODS: A retrospective analysis of all patients undergoing bowel resection for severe (American Fertility Society Stage IV) endometriosis at one institution between the years 1992 and 1996 was conducted using systematic chart review and follow-up by telephone interview. RESULTS: Twenty-nine patients were identified within the study period. The most frequent symptoms were pelvic pain, abdominal pain, rectal pain, and dysmenorrhea. Nearly all patients (93 percent) underwent low anterior resection of the rectum and distal sigmoid. Other intestinal procedures were appendectomy, terminal ileal resection, cecectomy, and sigmoid resection. Thirty-four percent of patients had simultaneous total abdominal hysterectomy and bilateral salpingooophorectomy. Complete follow-up was obtained on 26 patients (90 percent; mean follow-up 22.6 (range, 8-63) months). All patients (100 percent) reported subjective improvement. Forty-six percent of patients were "cured" according to the prospectively applied definition (resolution of symptoms without need for further medical or surgical therapy). The only variable analyzed that was associated with "cure" was concomitant total abdominal hysterectomy and bilateral salpingooophorectomy (odds ratio, 12; 95 percent confidence interval, 1.8-81.7). This association remained significant after correcting for age and the presence of gastrointestinal symptoms. CONCLUSION: Intestinal resection can be performed safely in most women with severe endometriosis and bowel involvement, although many of these patients experience persistent or recurrent symptoms. Total abdominal hysterectomy and bilateral salpingooophorectomy at the time of bowel resection correlates with improved outcome.

A physiologically based pharmacokinetic description of the oral uptake, tissue dosimetry, and rates of metabolism of bromodichloromethane in the male rat.

Bromodichloromethane (BDCM), a trihalomethane (THM) and water chlorination by-product, induces cancer in several tissues in experimental animals, including target tissue sites where increased incidences of human cancer have been linked to consumption of chlorinated water. The purpose of the present study was to examine the effects of vehicle of administration on the pharmacokinetics of orally administered BDCM and to further develop and validate a physiologically based pharmacokinetic (PBPK) model to describe BDCM absorption, tissue dosimetry, and rates of metabolism for both oil and 10% Emulphor vehicles. Estimates of oral absorption rate constants were determined by fitting blood and exhaled breath chamber concentration-time curves obtained following gavage of male F344 rats with 50 or 100 mg BDCM/kg in corn oil or 10% Emulphor using a previously published multicompartmental gastrointestinal tract submodel (Semino et al., Toxicology 117, 25-33, 1997) linked to a PBPK model. Independently estimated oral uptake and metabolic rate constants accurately described kidney BDCM concentrations and plasma bromide ion levels without adjustment. This observation increases our confidence in model structure and values of parameter estimates. Liver BDCM concentrations were simulated, but with less accuracy than kidney dosimetry simulations, following incorporation of BDCM loss to metabolism during sample preparation. This model describes BDCM tissue dosimetry and metabolism following oral gavage and can be utilized in estimating rates of formation of reactive metabolites in target tissues. Estimates of tissue dosimetry and levels of toxic intermediates can be incorporated into a risk assessment model for BDCM-induced toxicity and carcinogenicity.

The ability of HIV type 1 to use CCR-3 as a coreceptor is controlled by envelope V1/V2 sequences acting in conjunction with a CCR-5 tropic V3 loop.

Although infection by primary HIV type 1 (HIV-1) isolates normally requires the functional interaction of the viral envelope protein with both CD4 and the CCR-5 coreceptor, a subset of such isolates also are able to use the distinct CCR-3 receptor. By analyzing the ability of a series of wild-type and chimeric HIV-1 envelope proteins to mediate CCR-3-dependent infection, we have determined that CCR-3 tropism maps to the V1 and V2 variable region of envelope. Although substitution of the V1/V2 region of a CCR-3 tropic envelope into the context of a CCR-5 tropic envelope is both necessary and sufficient to confer CCR-3 tropism, this same substitution has no phenotypic effect when inserted into a CXCR-4 tropic HIV-1 envelope context. However, this latter chimera acquires both CCR-3 and CCR-5 tropism when a CCR-5 tropic V3 loop sequence also is introduced. These data demonstrate that the V1/2 region of envelope can, like the V3 loop region, encode a particular coreceptor requirement and suggest that a functional envelope:CCR-3 interaction may depend on the cooperative interaction of CCR-3 with both the V1/V2 and the V3 region of envelope.