Biologic characterization of chicken-derived H6N2 low pathogenic avian influenza viruses in chickens and ducks

Low pathogenic avian influenza H6N2 viruses were biologically characterized by infecting chickens and ducks in order to compare adaptation of these viruses in these species. We examined the clinical signs, virus shedding, and immune response to infection in 4-wk-old white leghorn chickens and in 2-wk-old Pekin ducks. Five H6N2 viruses isolated between 2000 and 2004 from chickens in California, and one H6N2 virus isolated from chickens in New York in 1998, were given intrachoanally at a dose of 1 x 10(6) 50% embryo infectious dose per bird. Oral-pharyngeal and cloacal swabs were taken at 2, 4, and 7 days postinoculation (PI) and tested by real-time reverse-transcriptase polymerase chain reaction for presence of virus. Serum was collected at 7, 14, and 21 days PI and examined for avian influenza virus antibodies by commercial enzyme-linked immunosorbent assay (ELISA) and hemagglutination inhibition (HI) testing. Virus shedding for all of the viruses was detected in the oral-pharyngeal swabs from chickens at 2 and 4 days PI, but only three of the five viruses were detected at 7 days PI. Only two viruses were detected in the cloacal swabs from the chickens. Virus shedding for four of the five viruses was detected in the oral-pharyngeal cavity of the ducks, and fecal shedding was detected for three of the viruses (including the virus not shed by the oral-pharyngeal route) in ducks at 4 and 7 days PI. All other fecal swabs from the ducks were negative. Fewer ducks shed virus compared to chickens. Both the chickens and the ducks developed antibodies, as evidenced by HI and ELISA titers. The data indicate that the H6N2 viruses can infect both chickens and ducks, but based on the number of birds shedding virus and on histopathology, the viruses appear to be more adapted to chickens. Virus shedding, which could go unnoticed in the absence of clinical signs in commercial chickens, can lead to transmission of the virus among poultry. However, the viruses isolated in 2004 did not appear to replicate or cause more disease than earlier virus isolates.

Efficacy of a replikin peptide vaccine against low-pathogenicity avian influenza H5 virus

In this study, the sequence of the H5 and PB1 genes of the low-pathogenic avian influenza virus (LPAI) A/Black Duck/NC/674-964/06 isolate were determined for replikin peptides and used to design and chemically synthesize a vaccine. The vaccine was used to immunize specific-pathogen-free (SPF) leghorn chickens held in Horsfall isolation units, by the upper respiratory route, at 1, 7, and 14 days of age. The birds were challenged at 28 days of age with 1 x 10(6) 50% embryo infective dose of the LPAI Black Duck/NC/674-964/06 H5N1 virus per bird. Oropharyngeal and cloacal swabs were collected at 2, 4, and 7 days postinoculation (PI) for virus detection by real-time RT-PCR. Serum was collected at 7, 14, and 21 days PI and examined for antibodies against avian influenza virus by the enzyme-linked immunosorbent assay and hemagglutination inhibition (HI) tests. Tissue samples for histopathology were collected from three birds per group at 3 days PI. The experimental design consisted of a negative control group (not vaccinated and not challenged) and a vaccinated group, a vaccinated and challenged group, and a positive control group (challenged only). None of the nonchallenged birds, the vaccinated birds, or the vaccinated and challenged birds showed overt clinical signs of disease during the study. A slight depression was observed in the nonvaccinated challenged birds on day 2 postchallenge. Although the numbers of birds per group are small, no shedding of the challenge virus was detected in the vaccinated and challenged birds, whereas oropharyngeal and cloacal shedding was detected in the nonvaccinated and challenged birds. HI antibodies were detected in the vaccinated and nonchallenged group as well as in the vaccinated and challenged group, but rising antibody titers, indicating infection with the LPAI challenge virus, were not detected. Rising HI titers were observed in the nonvaccinated and challenged group. In addition, no antibodies were detected in the nonchallenged birds. Noteworthy microscopic lesions were not observed in the vaccinated and challenged birds, whereas nonvaccinated-challenged birds had microscopic lesions consistent with infection with LPAI viruses. Taken together, these data indicate that a replikin peptide vaccine, specifically made against the H5N1 Black Duck/NC/674-964/06 isolate, and administered three times to the upper respiratory tract, was capable of protecting chickens from infection and from shedding of the homologous virus, which is extremely important because reduced virus shedding and transmission decreases the potential for H5 LPAI viruses to become HPAI viruses. The study is also important because it shows that the vaccine can be effectively mass-delivered to the upper respiratory tract.

Using DNA shuffling to create novel infectious bronchitis virus S1 genes: implications for S1 gene recombination

We employed the staggered extension process (StEP) to shuffle the S1 genes from four infectious bronchitis virus (IBV) strains representing four unique serotypes. Upon creating a shuffled S1 gene library, we randomly selected 25 clones and analyzed them by DNA sequencing. In total, eleven clones contained novel S1 gene recombinants. Based on sequence data, each recombinant was unique and contained a full-length open reading frame. The average number of crossovers per recombinant was 5 and the average number of point mutations was 1.3, leading mostly to non-synonymous amino acid changes. No recombinant contained sequences from all four parental genes and no recombinant contained any sequence from the distantly related Delaware 072 strain. Our data suggests that recombination between distantly related IBV strains within the S1 gene probably does not readily occur. This finding is extremely important in light of the common industry vaccination practice of mixing different live-attenuated IBV strains.

Development and Validation of a Real-Time Taqman®Polymerase Chain Reaction Assay for the Detection of Mycoplasma gallisepticum in Naturally Infected Birds

In this study, we report the development and validation of a real-time polymerase chain reaction (PCR) assay using a Taqman-labeled probe for the detection of Mycoplasma gallisepticum (MGLP assay). The MGLP assay was highly specific with a detection limit of 25 template copies per reaction and a quantification limit of 100 template copies per reaction. Validation of the assay was completed with 1247 samples (palatine cleft and tracheal swabs) from M. gallisepticum-positive and -negative chicken flocks. The MGLP assay was compared to an enzyme-linked immunosorbent assay (ELISA), a conventional polymerase chain reaction assay (mgc2 PCR), and isolation of M. gallisepticum from naturally infected flocks. A total of 805 samples collected from negative flocks, as verified by ELISA and/or mgc2 PCR, were negative by the MGLP assay. A total of 442 samples were collected from positive flocks, of which a total of 228 samples were positive by the MGLP assay. These results agreed for 98.87% of the samples when tested by mgc2 PCR. When comparing the MGLP assay with M gallisepticum isolation, the MGLP assay was more sensitive than isolation for detecting positive birds from a positive flock, 172/265 and 50/265, respectively. Overall, the MGLP assay and M. gallisepticum isolation agreed for 52.8% of the samples tested. In conclusion, the MGLP assay was highly specific, sensitive, and reproducible, and allowed the quantification of template copies directly from clinical samples.

Gliadel wafer in initial surgery for malignant glioma: long-term follow-up of a multicenter controlled trial

OBJECTIVE

Adjuvant systemic chemotherapy increases survival of primary malignant glioma patients beyond 12-18 months. The only interstitial chemotherapy treatment approved for malignant glioma is Gliadel wafer containing carmustine (BCNU) placed in the resection cavity at surgery. Analysis of a large trial by Westphal and colleagues (n = 240) showed a 29% risk reduction (P = 0.03) in the BCNU wafer-treated group over the course of the 30-month trial. Long-term follow-up of these patients was undertaken to determine the survival benefit at 2 and 3 years.

METHODS

Survival proportions for the placebo and treatment groups over the 56-month study were estimated by the Kaplan-Meier method. Multiple-regression analyses using the Cox proportional hazards model included prognostic factors of age, KPS, and tumor type. A secondary analysis was conducted for 207 GBM patients.

RESULTS

Of the 59 patients available for long-term follow-up, 11 were alive at 56 months: 9 had received BCNU wafers and 2 had received placebo wafers. Median survival of patients treated with BCNU wafers was 13.8 months vs 11.6 months in placebo-treated patients (P = 0.017) with a hazard ratio of 0.73 (P = 0.018), representing a 27% significant risk reduction. This survival advantage was maintained at 1, 2, and 3 years and was statistically significant (P = 0.01) at 3 years. Two of 207 GBM patients remained alive at the end of the follow-up period, both in the BCNU wafer-treated group.

CONCLUSION

Malignant glioma patients treated with BCNU wafers at the time of initial surgery in combination with radiation therapy demonstrated a survival advantage at 2 and 3 years follow-up compared with placebo.

Intracavitary Chemotherapy for Glioblastoma: Present Status and Future Directions

Considerable efforts have been invested to improve local control of the glioma disease although its infiltrative nature leading to whole brain involvement is a fundamental characteristic and antagonistic to this endeavour. The typically local recurrence of glioblastoma in about 80% of the cases has prompted intracavitary treatments of which presently only a biodegradable wafer containing carmustine has shown statistically significant benefit regarding survival in three phase III trials. Based on that proof of principle, many new developments are attempting to improve on this concept, introducing different agents with otherwise high systemic toxicity and poor penetration. New pharmacological formulations offer longer sustained release, better adaptation to the geometry of the resection cavity, and allow repeated administration. Should local recurrence become effectively controlled, significant progress can be made to increase survival with very limited local and virtually no systemic side effects. Since all agents so far show only limited activity against solid tumor, complete resection seems to be the prerequisite for effective local therapies.

Tolerability of recombinant-methionyl human neurotrophin-3 (r-metHuNT3) in healthy subjects

This phase I, double-blind, randomized, placebo-controlled study evaluated the safety of single and multiple (daily for 7 days) subcutaneous administrations of recombinant-methionyl human neurotrophin-3 (r-metHuNT3) in healthy human volunteers at seven doses, ranging from 3 to 500 microg/kg/day. No serious or life-threatening adverse events occurred. The most frequently recorded adverse effects were mild injection-site pain, diarrhea, and elevation of liver function tests. No change in neurologic function was noted with these dosing regimens. We conclude that r-metHuNT3 is safe and well tolerated in the dosages used in this study.

The ALSFRS-R: a revised ALS functional rating scale that incorporates assessments of respiratory function. BDNF ALS Study Group (Phase III)

The ALS Functional Rating Scale (ALSFRS) is a validated rating instrument for monitoring the progression of disability in patients with amyotrophic lateral sclerosis (ALS). One weakness of the ALSFRS as originally designed was that it granted disproportionate weighting to limb and bulbar, as compared to respiratory, dysfunction. We have now validated a revised version of the ALSFRS, which incorporates additional assessments of dyspnea, orthopnea, and the need for ventilatory support. The Revised ALSFRS (ALSFRS-R) retains the properties of the original scale and shows strong internal consistency and construct validity. ALSFRS-R scores correlate significantly with quality of life as measured by the Sickness Impact Profile, indicating that the quality of function is a strong determinant of quality of life in ALS.

Dose response to intraventricular glial cell line-derived neurotrophic factor administration in parkinsonian monkeys

A double-blinded study was conducted to evaluate the dose response of hemiparkinsonian rhesus monkeys to intracerebroventricular (ICV) injections of recombinant methionine human glial cell line-derived neurotrophic factor (GDNF). Thirty rhesus monkeys with stable hemiparkinsonian features were divided into six treatment groups (vehicle, 10, 30, 100, 300 and 1000 microg GDNF; n = 5/group). Each animal received 4 ICV administrations spaced at four week intervals. In addition, the animals were followed for 4 mo after the last injection. Standardized video taped behavioral tests were used to rate parkinsonian features using a nonhuman primate rating scale and assess side effects from treatment. Significant behavioral improvements were measured in animals receiving 100 to 1000 microg GDNF. One month after the last GDNF administration, parkinsonian features in animals receiving 100 and 1000 microg GDNF began to return to baseline levels. However, 300 microg GDNF recipients continued to display behavioral improvements. Parkinsonian features significantly improved were: bradykinesia, rigidity, posture and balance. The most common side effect was a transient weight loss after GDNF administration. Only one other side effect was observed, one animal receiving 1000 microg GDNF displayed dyskinetic movements. The results provide additional information for evaluating the possible clinical application of GDNF for treating Parkinson's disease.

Glial cell line-derived neurotrophic factor-levodopa interactions and reduction of side effects in parkinsonian monkeys

Glial cell line-derived neurotrophic factor (GDNF) stimulates the nigrostriatal dopaminergic pathway and improves motor functions in animal models of parkinsonism. Sinemet is currently the most widely used drug for treating Parkinson's disease. The present study has evaluated GDNF-Sinemet interactions in parkinsonian rhesus monkeys. Both GDNF and Sinemet, when given alone, significantly improved total parkinsonian scores. The response to Sinemet did not change after intracerebroventricular vehicle injections. In contrast, there was a functional interaction between GDNF and levodopa. When comparing the levodopa dose response before and after GDNF treatment, significant behavioral improvements were seen after trophic factor administration at every levodopa dose level except 500 mg. Adverse responses to Sinemet treatment alone in parkinsonian animals included vomiting, dykinesias, dystonias, and stereotypic movements. Combined GDNF-Sinemet treatment significantly reduced the occurrence of these levodopa-induced side effects, with a >90% decrease in adverse responses seen at the mid-Sinemet (250 mg levodopa-25 mg carbidopa) dose level. The only side effect from GDNF treatment was a transitory weight loss. Thus, combined GDNF-Sinemet treatment could be of therapeutic value in treating parkinsonism, by producing a greater functional response and by mitigating adverse responses to Sinemet treatment.

Glial cell line-derived neurotrophic factor: a novel therapeutic approach to treat motor dysfunction in Parkinson's disease

The discovery of the novel neurotrophic factor glial cell-line derived neurotrophic factor (GDNF) in 1993 sparked the interest of basic neuroscientists and clinicians alike. Since that time, many aspects of GDNF's physiology and pharmacology have been studied in great detail. GDNF has been shown to be a potent survival factor for dopaminergic neurons during development. GDNF also has been shown to be a survival factor and neurotrophic factor for nigrostriatal dopaminergic neurons in the adult. The factor also reverses behavioral deficits in a rodent and primate model of Parkinson's disease. The overall goal will be to discuss the pharmacology of GDNF in the context of a potential therapeutic use to treat Parkinson's disease. Thus, the following report presents a comprehensive review of the development of GDNF's pharmacology and evidence which supports the clinical use of GDNF to treat dopaminergic deficits and motor dysfunctions in Parkinson's disease.

Comparative effects of interferon-consensus 1, interferon-alpha 2a, and interferon-beta 1b on HLA expression and lymphoproliferation: a preclinical model for treatment of multiple sclerosis

Interferon-consensus 1 (IFN-Con 1) is a novel synthetic protein generated from codons for the most frequent amino acids in different type 1 IFNs. Compared with natural IFNs, IFN-Con 1 has been shown to have higher specific activity and antiproliferative activity and a higher ability to induce natural killer cells. In this study, the effects of IFN-Con 1 were compared with those of IFN-beta 1b and IFN-alpha 2a on HLA expression and lymphoproliferation. Human umbilical vein endothelial cells (HUVEC) express HLA class I but not class II molecules; however, both class I and class II molecules can be upregulated by IFN-gamma. IFN-Con-1 shared with IFN-beta 1b and IFN-alpha 2a the capacity to enhance HLA class I expression on HUVEC, alone and in combination with IFN-gamma. Although IFN-Con 1 had no effect on the basal expression of HLA class II molecules, it inhibited the IFN-gamma-induced class II expression on the HUVEC in a dose-dependent fashion. When this effect was compared among the three IFNs on mass basis, IFN-Con 1 activity was intermediate between that of IFN-beta 1b and IFN-alpha 2a. IFN-Con 1 also demonstrated an inhibitory effect on mitogen-driven lymphoproliferation similar to that of IFN-alpha 2a and exceeded that of IFN-beta 1b. The results indicate that IFN-Con 1 has immunomodulatory effects similar to those of IFN-beta 1b and IFN-alpha 2a, which could be relevant to the treatment of autoimmune and virus-mediated diseases.

Organization, sequence and regulation of expression of the murine Hoxa-7 gene

The genomic sequence of Hoxa-7 (encoding the HOXa-7 homeobox protein), including the coding region (0.7 kb), flanked by a 5'-upstream region (2.8 kb), a 3'-downstream region (1 kb) and interrupted by an intron (995 bp), was determined. Northern blot analysis indicated the transcript size of Hoxa-7 to be 2.1-2.4 kb. Reverse transcription-PCR and primer extension analysis established the 5'-boundary of the mRNA to be in the region 1166 nt upstream from the start codon. Transient transfection of various Hoxa-7::cat constructs in NIH 3T3 cells was used to characterize the transcriptional activity of the 5'-flanking region of the gene. Constructs containing 544, 274 and 71 bp of the region upstream from the transcription start point (tsp) exhibited 78, 203 and 407%, respectively, of the activity shown by a control construct containing 739 bp of the upstream region. These data suggested the presence of negative regulatory elements in the region from 544 to 71 bp upstream from the tsp.

Comparison of the promoter region of the human and porcine choline acetyltransferase genes: localization of an important enhancer region

Genomic clones of human and porcine choline acetyltransferase were obtained by screening genomic libraries with synthetic oligonucleotides. The human and porcine genes exhibit significant conservation of both their intron/exon structure and the nucleotide sequence in their 5' flanking regions. However, the two genes differ in several respects, including the absence of a "TATA" box in the human gene and differences in the position of the methionine start codon. Analysis of the promoter region of the two genes has led to the localization of an enhancer element that appears necessary for efficient transcription of the gene.

Salvage trial of trimetrexate-leucovorin for the treatment of cerebral toxoplasmosis in patients with AIDS

The clinical efficacy of trimetrexate, a dihydrofolate reductase inhibitor with potent in vitro antitoxoplasma activity, was assessed in 9 sulfonamide-intolerant patients with AIDS and biopsy-proven cerebral toxoplasmosis. The 9 patients were treated for 28-149 days with trimetrexate (30-280 mg/m2/day) plus leucovorin (20-90 mg/m2 every 6 h). Radiographic responses were documented in 8 patients, and clinical responses in 5 patients. Despite continued therapy, all patients deteriorated clinically and radiographically within 13-109 days of their initial improvement. Trimetrexate at very high doses for extended periods was not associated with serious toxicity. Trimetrexate alone had dramatic but transient activity in sulfonamide-intolerant patients and thus is not adequate as single-agent therapy for AIDS-associated toxoplasmosis.

Inhibition of rat brain galactocerebroside sulfotransferase by triazine aromatic dyes: interaction with the 3'-phosphoadenosine 5'-phosphosulfate binding site

The mechanism of inhibition of rat brain cerebroside sulfotransferase (EC 2.8.2.11) by a series of triazine aromatic dyes was examined. These dyes are putative site-specific probes of the "dinucleotide fold". All of the dyes examined were competitive inhibitors of cerebroside sulfotransferase with respect to 3'-phosphoadenosine 5'-phosphosulfate (PAPS) binding. In addition, the binding of the dye, Congo Red, to the sulfotransferase was associated with a red shift in its absorption spectrum. Based on these results, it is suggested that rat brain cerebroside sulfotransferase contains a "dinucleotide fold" as a structural feature of the protein.