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Biomedical subjects

W J Bean

Publications and source records attributed to W J Bean.

At least 37 records · Page 2Linked to original sources
PubMed1989

What is the potential of avirulent influenza viruses to complement a cleavable hemagglutinin and generate virulent strains?

A large pool of avirulent influenza viruses are maintained in the wild ducks and shorebirds of the world, but we know little about their potential to become virulent. It is well established that the hemagglutinin (HA) is pivitol in determining virulence and that a constellation of other genes is also necessary (R. Rott, M. Orlich, and C. Scholtissek, 1976, J. Virol. 19, 54-60). The question we are asking here is the ability of avirulent influenza viruses to provide the gene constellation that will complement the HA from a highly virulent virus and for the reassortant to be virulent. Reassortant influenza viruses were prepared between ultraviolet treated A/Chicken/Pennsylvania/1370/83 (H5N2) [Ck/Penn] and influenza viruses from natural reservoirs. These viruses included examples of the predominant subtypes in wild ducks, shorebirds, and domestic poultry. Attention was given to the influenza viruses from live poultry markets, for it is possible that these establishments may be important in mixing of influenza genes from different species and the possible transmission to domestic and mammalian species. The reassortants were genotyped by partial sequencing of each gene and were tested for virulence in chickens. Each of the reassortants contained the hemagglutinin and matrix (M) genes from Ck/Penn and a majority of genes from the viruses from natural reservoirs indicating a preferential association between the HA and M genes. The reassortants containing multiple genes from wild ducks and a cleavable HA were avirulent indicating that the gene pool in ducks may not have a high potential to provide genes that are potentially virulent. In contrast, a disproportionate number of viruses from shorebirds and all avirulent H5N2 influenza viruses from city markets provided a gene constellation that in association with cleavable H5 HA were highly virulent in chickens. An evolutionary tree based on oligonucleotide mapping established that the H5N2 influenza viruses from birds in city markets are closely related.

Animals↗
PubMed1989

Biologic potential of amantadine-resistant influenza A virus in an avian model.

Amantadine has been accepted for both the treatment and prophylaxis of influenza A virus infections. Although amantadine-resistant mutants have been shown to be readily generated both in the laboratory and in children treated with rimantadine, little is known about their biologic properties, such as genetic stability, transmissibility, or pathogenicity, compared with the parental virus. This study examined these properties using an avian influenza virus, A/chicken/Pennsylvania/1370/83 (H5N2). Variants that were amantadine-resistant, virulent, and capable of competing with wild-type virus for transmission to susceptible hosts in the absence of the drug were selected. These amantadine-resistant variants were also genetically stable, showing no reversion to wild-type after six passages in birds over a period of greater than 20 d. Thus, these virus variants had no detectable biologic impairment. The mutations conferring drug resistance were in the M2 polypeptide and were identical to mutations previously described in human amantadine-resistant virus. These results suggest that resistant mutants may have the potential to threaten the effective use of amantadine and rimantadine for the control of epidemic influenza.

Amantadine↗
PubMed1988

Balloon dilatation of urethral strictures.

Balloon dilatation of the urethra in 9 male patients with either post-inflammatory or post-traumatic strictures was successfully performed. This procedure is primarily indicated in those patients with unsatisfactory results using conventional dilatation with metal sounds. A flexible endoscope was used for guide wire passage and fluoroscopic guidance for positioning the balloon and assuring complete dilatation of the urethral strictures or vesical neck contracture. In this manner, dilatation to 36 F can be performed in a relatively atraumatic manner with minimal discomfort.

Catheterization↗
PubMed1987

Molecular analysis of the hemagglutinin genes of Australian H7N7 influenza viruses: role of passerine birds in maintenance or transmission?

In 1985 a fowl plague-like disease occurred in chickens in Lockwood, Victoria, Australia and caused high mortality. An H7N7 influenza virus was isolated from the chickens (A/Chicken/Victoria/1/85); additionally, an antigenically similar virus was isolated from starlings (A/Starling/Victoria/5156/85) and serological evidence of H7N7 virus infection was found in sparrows. Antigenic analysis with monoclonal antibodies to H7, oligonucleotide mapping of total vRNA, and sequence analysis of the HA genes established that the chicken and starling influenza viruses were closely related and probably came from the same source. There was high nucleotide sequence homology (95.3%) between the HA genes of A/Chick/Vic/85 and a fowl plague-like virus isolated from chickens in Victoria 9 years earlier [A/Fowl/Vic/76 (H7N7)]. The sequence homologies indicated that the A/Chick/Vic/85 and A/Fowl/Vic/76 were derived from a common recent ancestor, while another recent H7N7 virus, Seal/Mass/1/80 originated from a different evolutionary lineage. Experimental infection of chickens and starlings with A/Chick/Vic/1/85 (H7N7) was associated with high mortality (100%), transmission to contact birds of the same species, and virus in all organs. In sparrows one-third of the birds died after infection and virus was isolated from most organs; transmission to contact sparrows did not occur. In contrast, the H7N7 virus replicated in ducks and spread to contact ducks but caused no mortality. These studies establish that the host species plays a role in determining the virulence of avian influenza viruses, and provide the first evidence for transmission of virulent influenza viruses between domestic poultry and passerine birds. They support the hypothesis that potentially virulent H7N7 influenza viruses could be maintained in ducks where they cause no apparent disease and may sometimes spread to other wild birds and domestic poultry.

Amino Acid Sequence↗
PubMed1986

Molecular changes in A/Chicken/Pennsylvania/83 (H5N2) influenza virus associated with acquisition of virulence.

One of the unresolved questions concerning the acquisition of virulence by the A/Chicken/Pennsylvania/83 (H5N2) influenza virus is which gene segments other than the hemagglutinin (HA) showed changes that were relevant. To answer this question, reassortants were made possessing the hemagglutinin gene of the virulent virus and the seven other genes from the avirulent parent. Since both the virulent and avirulent H5N2 strains are antigenically almost indistinguishable, it was necessary to transfer the genes of interest to a "carrier" virus before the appropriate reassortment could be selected. The gene compositions of the reassortants was established by a combination of sequence analysis and migration on polyacrylamide gels. These analyses established that the avirulent influenza virus present in April 1983 possessed seven of the eight gene segments necessary for virulence; mutation(s) in the HA gene were required for acquisition of virulence. Other viruses such as A/Seal/Mass/1/80 (H7N7) could provide the other genes necessary for virulence. Two changes in the HA have been associated with the acquisition of virulence; these are at amino acid residues 23 and 78 (H3 numbering) (Y. Kawaoka and R.G. Webster, Virology, 146, 130-137 (1985]. Isolation of an amantadine-resistant avirulent revertant virus provided the opportunity to determine which of the two amino acid changes in HA is critical. Sequence analysis of the revertant virus revealed amino acid changes at residues 23 in HA1 and 40 in HA2 (H3 numbering). The change at residue 23 of HA1 is probably associated with reversion to avirulence, of cleavability of HA, and inability to plaque in tissue culture without trypsin; while the change at residue 40 of HA2 may be associated with the amantadine-resistant phenotype. These studies establish that a single critical point mutation in the hemagglutinin gene of the avirulent A/Chicken/Pennsylvania/1/83 (H5N2) was probably all that was required to produce the highly virulent Chicken/Pennsylvania virus; the avirulent virus already possessed the other genes necessary for virulence.

Amino Acid Sequence↗
PubMed1986

Forceps extraction of ureteral stones.

Ureteroscopy and pyeloscopy in association with ultrasonic lithotripsy for extraction of ureteral stones has, in most instances, eliminated the need for open surgical intervention. Four ureteral stones were successfully extracted by the technique described using flexible cup biopsy forceps introduced through a Teflon sheath. This method was used when basket extraction, ureteroscopy, and other forms of endoscopic stone manipulation were unsuccessful. Two ureteral stones were removed by the transurethral route, and two were removed through a percutaneous nephrostomy tract. There has been little morbidity with this procedure, and patients have returned to normal activity within several days of hospital discharge.

Aged↗
PubMed1986

Computed tomography of oleothorax.

Oleothorax as therapy for pulmonary tuberculosis was discontinued some 35 years ago. An oleothorax may expand and cause respiratory distress. Additional complications include bronchopleural fistula and cutaneous fistula. Computed tomography has not previously been used to evaluate oleothorax. This case report describes the use of computed tomography in a patient with a symptomatic oleothorax.

Aged↗
PubMed1986

Balloon dilation of the ureter: a means to facilitate passage of ureteral and renal calculi.

Dilation of the ureter with a balloon catheter, 20 cm. long and 6 mm. in diameter, passed over a guide wire introduced into the ureter in a retrograde or antegrade fashion has been followed by prompt painless passage of calculi as large as 6 mm. in diameter in 3 patients. Limited radiographic evaluation has revealed no significant sequelae. Our limited experience indicates that it is a safe and expedient method to facilitate passage of ureteral and renal calculi.

Aged↗
PubMed1986

Vaccination as a strategy to reduce the emergence of amantadine- and rimantadine-resistant strains of A/Chick/Pennsylvania/83 (H5N2) influenza virus.

The influenza A virus (A/Chick/Pennsylvania/83 (H5N2) that caused up to 80% mortality in chickens provided a model system for testing the efficacy of chemotherapeutic agents against highly virulent influenza virus. Amantadine and rimantadine administered to chickens in drinking water were efficacious both prophylactically and therapeutically. However, under conditions simulating natural transmission of virus amantadine and rimantadine-resistant viruses arose and were transmitted to contact birds, causing mortality. Simultaneous administration of inactivated H5N2 vaccine and amantadine provided protection. Thus, chemotherapy may be useful in the treatment of a highly pathogenic influenza virus outbreak in humans or other animals when used in combination with vaccine.

Adamantane↗
PubMed1986

Osteoid osteoma in unusual locations: detection and diagnosis.

We have reported two unusual cases of osteoid osteoma in small bones of the hand and foot. The roentgenographic appearance of a radiolucent area with a sclerotic rim in these regions and in the proper clinical setting must raise the possibility of osteoid osteoma. Computerized tomography can accurately demonstrate the highly vascular nidus.

Adolescent↗
PubMed1986

Characterization of two influenza A viruses from a pilot whale.

Influenza A viruses of the H13N2 and H13N9 subtypes were isolated from the lung and hilar node of a pilot whale. Serological, molecular, and biological analyses indicate that the whale isolates are closely related to the H13 influenza viruses from gulls.

Animals↗
PubMed1986

Balloon dilatation of esophageal strictures.

Esophageal dilatation is a safe and effective method for treating most esophageal strictures. Balloon dilatation is primarily used in those strictures in which conventional techniques were initially unsuccessful. We have successfully treated 13 patients with severe esophageal strictures of both benign and malignant etiologies. The patients subjectively felt better and weight gain was uniform. The patients were able to maintain adequate patency of the esophagus with bougie and self-dilatation. The length of follow-up ranged from 2 to 30 months. The various techniques used for balloon dilatation of esophageal strictures are presented. No serious complications were encountered. Dilatation by balloon catheter appears to be a safe method to dilate severe strictures and provides maximum patient benefit with minimal trauma and morbidity.

Adult↗
PubMed1985

Characterization of virulent and avirulent A/chicken/Pennsylvania/83 influenza A viruses: potential role of defective interfering RNAs in nature.

In April 1983, an influenza virus of low virulence appeared in chickens in Pennsylvania. Subsequently, in October 1983, the virus became virulent and caused high mortality in poultry. The causative agent has been identified as an influenza virus of the H5N2 serotype. The hemagglutinin is antigenically closely related to tern/South Africa/61 (H5N3) and the neuraminidase is similar to that from human H2N2 strains (e.g., A/Japan/305/57) and from some avian influenza virus strains (e.g., A/turkey/Mass/66 [H6N2]). Comparison of the genome RNAs of chicken/Penn with other influenza virus isolates by RNA-RNA hybridization indicated that all of the genes of this virus were closely related to those of various other influenza virus isolates from wild birds. Chickens infected with the virulent strain shed high concentrations of virus in their feces (10(7) 50% egg infective dose per g), and the virus was isolated from the albumin and yolk of eggs layed just before death. Virus was also isolated from house flies in chicken houses. Serological and virological studies showed that humans are not susceptible to infection with the virus, but can serve as short-term mechanical carriers. Analysis of the RNA of the viruses isolated in April and October by gel migration and RNA-RNA hybridization suggested that these strains were very closely related. Oligonucleotide mapping of the individual genes of virulent and avirulent strains showed a limited number of changes in the genome RNAs, but no consistent differences between the virulent and avirulent strains that could be correlated with pathogenicity were found. Polyacrylamide gel analysis of the early (avirulent) isolates demonstrated the presence of low-molecular-weight RNA bands which is indicative of defective-interfering particles. These RNAs were not present in the virulent isolates. Experimental infection of chickens with mixtures of the avirulent and virulent strains demonstrated that the avirulent virus interferes with the pathogenicity of the virulent virus. The results suggest that the original avirulent virus was probably derived from influenza viruses from wild birds and that the virulent strain was derived from the avirulent strain by selective adaptation rather than by recombination or the introduction of a new virus into the population. This adaptation may have involved the loss of defective RNAs, as well as mutations, and thus provides a possible model for a role of defective-interfering particles in nature.

Animals↗
PubMed1985

Chemotherapy and vaccination: a possible strategy for the control of highly virulent influenza virus.

The influenza A virus [A/Chicken/Pennsylvania/1370/83 (H5N2)] that caused up to 80% mortality among chickens provided a model system for testing the efficacy of chemotherapeutic agents against highly virulent influenza virus. Amantadine and rimantadine administered in drinking water were efficacious both prophylactically and therapeutically. However, under conditions simulating natural transmission of virus, amantadine- and rimantadine-resistant viruses arose and were transmitted to other birds in contact with the infected chickens, causing mortality. Simultaneous administration of inactivated H5N2 vaccine and amantadine provided protection. Thus, chemotherapy may be useful in the treatment of a highly pathogenic influenza virus outbreak in humans or other animals when used in combination with vaccine.

Adamantane↗