Consideration of inactivated rabies vaccines as oral immunogens of wild carnivores

An experimental beta-propiolactone (BPL)-inactivated rabies virus vaccine was evaluated for the oral immunization of captive raccoons (Procyon lotor) and red foxes (Vulpes vulpes). None of 10 red foxes administered a single 1.0 ml dose of BPL-inactivated rabies virus vaccine (PM strain; 100 or 500 micrograms protein) per os developed detectable anti-rabies virus-neutralizing antibodies (VNA) at any time over 8 wk of observation. Foxes were excluded from further study. In two different groups of five to six raccoons, each administered a single 1.0 ml dose of BPL-inactivated rabies virus vaccine (ERA strain) per os, at concentrations of 100 or 400 micrograms protein, only a single animal in each group demonstrated evidence of seroconversion within 4 wk. In contrast, instillation of a single dose (500 micrograms protein) of BPL-inactivated rabies virus vaccine (ERA strain), directly into the small intestine via fiberoptic endoscope, or ERA vaccine (800 micrograms protein) instillation to the buccal cavity by needle-less syringe, resulted in the production of rabies-specific VNA and protection against lethal rabies infection in three of six, and in four of six raccoons, respectively; all seven control raccoons succumbed to street virus challenge. These preliminary challenge studies, while somewhat encouraging, demonstrate that considerable quantities of purified viral antigen are required for even minimal oral efficacy against lethal rabies infection. At the present time, therefore, potent, self-replicating, attenuated, or recombinant viruses offer the most versatile, economic, efficacious, and safe solutions to terrestrial rabies control of free-ranging carnivores.

Trap-vaccinate-release and oral vaccination for rabies control in urban skunks, raccoons and foxes

Two rabies control tactics, trap-vaccinate-release (T-V-R) and oral vaccination were used for the control of rabies in skunks (Mephitis mephitis), raccoons (Procyon lotor), and foxes (Vulpes vulpes) in metropolitan Toronto, Canada. Using T-V-R, a mean of 45% to 72% (95% confidence limits of 40% to 81%) of the skunks and a mean of 17% to 68% (95% confidence limits of 14% to 76%) of the raccoons in a 60 km2 area of Toronto were vaccinated against rabies between 1987 and 1991. The area has been free of skunk rabies from May 1989 to April 1992. Forty-five rabies cases were diagnosed during 1980 to 1986. In contrast, only three skunk cases have been reported since the vaccination program began in July 1987. The T-V-R area also remained rabies free during an epizootic of skunk rabies in metropolitan Toronto during 1991. Following distribution of rabies vaccine-baits throughout the ravines of metropolitan Toronto, June 1989 to December 1991, 46% to 80% of the Toronto fox population was immunized during 1989, 1990 and 1991. Only one case of fox rabies was reported in metropolitan Toronto since vaccination began, compared to 80 cases reported between 1982 and 1988. The area has been free of reported fox rabies from October 1990 to April 1992.

Studies on efficacy and stability of a vaccine bait containing ERA strain of rabies virus propagated in a BHK-21 cell line

In a dose response study in foxes, the median protective dose of ERA BHK21 vaccine in a blister pack bait was 10(6.0) tissue culture infective doses (TCID)/mL, while artificially aged baits with titers of 10(6.3) TCID/mL induced seroconversion in 78% of foxes. There was no significant difference in the development of antibodies in foxes receiving 1, 2 or 3 mL volumes of vaccine in the bait. When baits were exposed to the elements and fed to foxes over a 21 day period, 85% of the animals seroconverted. Age, sex and the way in which the vaccine container was contacted did not appear to be factors in the responses of these animals. Juvenile foxes, approximately six months of age, were marked more readily with the tetracycline bait marker than older animals. Approximately 25% of foxes did not appear to respond well to vaccination and the titer of the vaccine was a critical factor in producing seroconversion in these animals.

Oral rabies vaccination of skunks and foxes with a recombinant human adenovirus vaccine

A new recombinant rabies vaccine (human adenovirus 5 containing the rabies glycoprotein gene) was given to striped skunks (Mephitis mephitis) and red foxes (Vulpes vulpes). Groups of skunks received the vaccine in baits, by direct instillation into the mouth, or intramuscularly. Foxes were given vaccine by direct instillation into the oral cavity (DIOC). Selected groups of vaccinated skunks and foxes were challenged with street rabies virus. There were high rates of seroconversion (generally with high antibody titers) in both foxes and skunks, with survival of all challenged vaccinated animals (all challenge controls developed rabies). In skunks, vaccine given DIOC was effective over a broad range of doses (10(8.7), 10(7.6) and 10(6.4) median tissue culture infective doses). There was no evidence of pathogenic effects. The results indicate that this adenovirus recombinant has considerable potential as a wildlife oral rabies vaccine.

Modification of impression cytology for in-office use

An in-office procedure for assessment of the conjunctival epithelium, goblet cells, mucin and immune cells is described. The collection of three samples from each eye greatly improves cell harvest and increases reproducibility of the technique called impression cytology. The protocol and its pitfalls are discussed as well as the numerous applications of impression cytology.

The microbiology of peritonsillar sepsis

Pus obtained by needle aspiration of 91 peritonsillar abscesses was examined microbiologically. A positive culture was obtained in 55 patients (60 per cent). Sixty-four bacteriological isolates were grown. Forty patients had a pure growth of a single organism, of which 21 (53 per cent) were beta Haemolytic streptococci. Pure growths of Staphylococcus aureus were found in only three patients. Fifteen patients had mixed organisms, including anaerobes, in their pus and the resistance to penicillin was low. Only the bacteroides species were generally penicillin resistant. The vast majority of patients made a good recovery following needle drainage of the abscess and treatment with parenteral penicillin. The patients with a mixture of penicillin sensitive and penicillin resistant organisms also made a good clinical recovery following needle drainage and administration of parenteral penicillin. The relevance of these findings in the pathogenesis and management of peritonsillar sepsis is discussed.

Sequence analysis of putative E3 and fiber genomic regions of two strains of canine adenovirus type 1

The nucleotide sequences of the genomes of two strains of canine adenovirus, type 1 (Glaxo and CLL) have been determined within the region spanning approximately 0.80-0.91 map unit. Homology comparisons with other adenoviral DNAs indicate that this region contains part of the hexon-associated protein (pVIII) precursor gene on the left, and a 57-kDa fiber-encoding gene on the right. In both viral strains, the sequences of these genes are identical. Accepting the generally highly conserved nature of the genetic organization of adenoviral genomes, the 1136-bp sequence between them would include the canine equivalent of the human adenoviral E3 region. In the Glaxo strain, which is nonattenuated, this sequence contains only two R-strand open reading frames capable of coding for polypeptides of 60 residues or more. One of these appears to code for a transmembrane glycoprotein of 194 amino acid residues. Neither ORF, however, shows significant homology with any other known adenoviral DNA or protein sequence. The corresponding region in the attenuated strain CLL is almost identical with that of the Glaxo, but with a 325-bp deletion resulting in a fusion of the two ORFs. It seems, therefore, that neither ORF is essential for viral replication in vitro, since the CLL strain replicates just as efficiently as the Glaxo. The suggestion is made that the attenuation of the CLL strain may be related to the nonfunctionality of its E3 gene product(s).

The management of peritonsillar sepsis by needle aspiration

172 consecutive patients admitted with suspected unilateral peritonsillar sepsis were studied. Needle aspiration of the peritonsillar space was performed, and they were all then treated with intravenous antibiotics (usually benzylpenicillin). Any pus obtained was cultured. The aspiration was repeated if the patient was not improving after 24 h. A quantity of pus was aspirated at the first attempt from 91 patients (53%); 82 of these required no further aspiration but 7 required a further single aspiration and 2 required a further 2 aspirations before resolution of the sepsis. 71 of the 81 patients (88%) from whom pus had not been aspirated, and who were therefore initially considered to have peritonsillar cellulitis, required no further aspirations. However, 6 subsequently drained pus spontaneously and 4 produced a positive aspirate on a second occasion. Four patients required a change in their antibiotic therapy. We have found the combination of needle aspiration and parenteral antibiotics to be an effective treatment of peritonsillar sepsis. All patients were spared the unpleasant and painful experience of an incision and drainage procedure.

Hearing aid prescribing: is the specialist opinion necessary?

A restructuring of the service for provision of hearing aids has been proposed by the Royal National Institute for the Deaf. This is based on the assumption that very few patients referred for hearing aids have significant ear disease and it is not necessary for them to see an ENT specialist. The case notes of 200 consecutive patients referred to the Hearing Aid clinic were reviewed. In only half of these would a hearing aid have been prescribed without a specialist opinion. The remainder either did not need a hearing aid or required further investigation and surgical or medical treatment. In addition there was significant evidence of lack of expertise amongst General Practitioners in recognizing ear disorders. It is imperative that any patient requiring a hearing aid be seen by someone experienced in otology rather than be dealt with by the General Practitioner alone.

Fanconi's anaemia and post-cricoid carcinoma

A case of post-cricoid carcinoma, occurring in a patient with Fanconi's anaemia is presented. The case illustrates the rare association of the two diseases. The problems with the management of such a case are discussed.

Vaccinia recombinant virus expressing the rabies virus glycoprotein: safety and efficacy trials in Canadian wildlife

Twenty-six meadow voles (Microtus pennsylvanicus), ten woodchucks (Marmota monax), thirteen grey squirrels (Sciurus carolinensis), thirteen ring-billed gulls (Larus delawarensis), six red-tailed hawks (Buteo jamaicensis) and eight great horned owls (Bubo virginianus) received vaccinia virus recombinant expressing the rabies virus glycoprotein (V-RG) by direct instillation into the oral cavity. Each of ten coyotes (Canis latrans) received the virus in two vaccine-laden baits. Several voles and most of the gulls died from diseases unrelated to vaccination during the observation period, but all other animals remained healthy and survived. These deaths from causes other than vaccination and the absence of any lesions suggestive of vaccinia infection indicate that it is unlikely that any animal suffered or died as a result of V-RG administration. In addition several animals showed an unexpected high level of rabies neutralizing antibodies.

Intramuscular vaccination of skunks and raccoons against rabies

Live-captured striped skunks (Mephitis mephitis) and raccoons (Procyon lotor) were immunized with inactivated rabies vaccine by intramuscular injection and released at the point of capture during a rabies control program in Metropolitan Toronto (Ontario, Canada). Serum samples collected prior to and following vaccination revealed that 100% of the skunks and 98% of the raccoons seroconverted. Rabies antibody was still detectable 314 to 757 days postvaccination. Five of six skunks vaccinated in the laboratory survived challenge with rabies virus 90 days postvaccination. To our knowledge, this is the first documentation of the successful seroconversion of skunks and raccoons vaccinated against rabies in the field.

Rigid contact lens base curve constancy between wet and dry lens storage conditions

The purpose of this study was to investigate dry storage of rigid gas-permeable contact lenses as an alternative to wet storage. This study evaluated the constancy of lens base curve between the two storage methods for lens materials that spanned the spectrum of oxygen permeability values. The differences found in lens base curve between wet and dry storage for any lens material evaluated did not reach a level considered to be clinically significant, although differences in average base curve constancy did exist among the lens materials. Base curve change did not increase with increasing lens material oxygen permeability value (Dk).

Radiation induced tumours of the pharynx--can they be avoided?

Three patients who developed a post-cricoid carcinoma 5-21 years after radiotherapy for carcinoma of the larynx are presented. These patients received radiotherapy when they were young. It is suggested that alternative forms of treatment, especially partial laryngectomy with the aid of a laser should be considered in the primary management of small tumours of the larynx of young patients.

Ineffectiveness and comparative pathogenicity of attenuated rabies virus vaccines for the striped skunk (Mephitis mephitis)

Three attenuated rabies virus vaccines (SAD-B19, ERA/BHK-21, AZA 2) were compared for efficacy and safety in the striped skunk (Mephitis mephitis) by the oral and intranasal routes. The SAD-B19 and ERA/BHK-21 vaccines were given orally; all three vaccines were given intranasally. Oral administration of SAD-B19 and ERA/BHK-21 vaccines induced neither seroconversion nor significant protection against rabies challenge. One skunk which consumed a SAD-B19 vaccine-laden bait succumbed to vaccine-induced rabies. Intranasal instillation of the three vaccines resulted in the deaths of two of six (AZA 2), three of six (ERA/BHK-21) and six of six (SAD-B19) skunks.

A recombinant human adenovirus vaccine against rabies

Rabies continues to be a serious problem in both developed and developing nations due to the reservoir of rabies virus in wildlife vectors. The control and worldwide eradication of rabies depends on the development of safe, effective, and economical vaccines that might be used in preexposure vaccination programs for humans and animals. To this end an infectious human adenovirus type 5 recombinant virus that contains the rabies glycoprotein gene, and which may serve as the prototype for a new class of vaccines against rabies, was constructed and tested. This recombinant, when administered by either the parenteral or oronasal route, was highly effective in eliciting good levels of rabies-neutralizing antibodies in the sera of dogs and mice. Mice immunized by the recombinant virus were protected from lethal intracerebral challenge with rabies virus.

Mutants of rabies viruses in skunks: immune response and pathogenicity

In studies to develop an oral rabies vaccine for wildlife, the immune response to and pathogenicity of two types of mutants of rabies viruses were examined. Forty-five small plaque mutants were selected from cultures of ERA rabies virus treated with 8-azaguanine or 5-fluorouracil and tested for pathogenicity in mice. Two of these mutants AZA 1 and AZA 2 (low pathogenicity in mice) were given to skunks by oral (bait), intestinal (endoscope) and intramuscular routes. Additionally, challenge virus standard (CVS) rabies virus and mutants of this and ERA rabies virus (CVS 3766 and 3713, and ERA 3629) that were resistant to neutralization by specific antiglycoprotein monoclonal antibodies (and apathogenic in mice) were tested by various routes in skunks. Skunks given AZA 1 and AZA 2 were challenged at three months postinoculation with street rabies virus. After oral administration, there were very low rates of seroconversion with AZA 1 and AZA 2 and on challenge only 2/7 given AZA 1 and 1/8 given AZA 2 survived. None of the skunks given the other mutants orally seroconverted. AZA 2 produced a high rate of seroconversion (8/8) by the intestinal route and all challenged skunks in this group survived (7/7). All skunks vaccinated intramuscularly with AZA 1 (4/4) or AZA 2 (4/4) developed high levels of rabies neutralizing antibodies and survived challenge. The mutant CVS 3766, while apathogenic when given intracerebrally to adult mice, was consistently pathogenic by this route (and intranasally) in skunks. These results demonstrate that skunks are highly resistant to oral immunization by live rabies virus vaccines and that pathogenicity (by intracerebral route) of the mutant CVS 3766 is markedly different in mice and skunks.

Synthesis and structure-activity relationships of a series of anxioselective pyrazolopyridine ester and amide anxiolytic agents

A series of 1-substituted 4-amino-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid esters and amides were synthesized and screened for anxiolytic activity in the shock-induced suppression of drinking (SSD) test. The compounds were also tested for their ability to displace [3H]flunitrazepam (FLU) from brain benzodiazepine (BZ) binding sites. Many compounds were active in these screens and, additionally, demonstrated a selectivity for the type 1 BZ (BZ1) receptor over the type 2 BZ (BZ2) receptor as indicated by Hill coefficients significantly less than unity and by analysis of [3H]FLU binding results from different brain regions. Based on the results of structure-activity studies of these compounds, a hypothesis was proposed to explain the structural features necessary for optimal interaction with brain BZ receptors. A detailed pharmacological evaluation of one of the most potent behaviorally active compounds (27) demonstrated it to be BZ1 selective; also, in comparison to diazepam, 27 showed minimal sedative and alcohol interactive properties at therapeutically effective doses.

Incomplete particles of canine adenovirus type 1: occurrence and structure

Replication of canine adenovirus (CAV) type 1 in dog kidney (DK) cells has been found to generate particles containing double-stranded DNA molecules of size 6-9 kbp with protein moieties at their 5' termini. The particles formed a discrete band in CsCl gradients at a density intermediate to that of intact virions and empty capsids. Electron microscopy demonstrated that they were morphologically similar to intact virions. Restriction enzyme digests and hybridization experiments revealed the existence of DNA molecules consisting of sequences extending from left and right termini of the intact genome. The subgenomic DNAs, therefore, appear to be viral DNA with the majority (24-26 kbp) of its internal sequences deleted. Agarose gels of viral DNA isolated from DK cells infected with plaque-purified CAV revealed, in addition to the intact viral genome, one or more sharp, well-defined subgenomic DNA bands, the sizes of which varied from approximately 6 to 9 kbp among individual isolates. Incomplete particles of this sort were found in the two strains of CAV type 1 tested (Connaught ICHV and Glaxo), but not in a strain of CAV type 2 (Manhattan).

Experience with the home-care of tracheotomised paediatric patients

Many infants with tracheotomies remain cannulated for prolonged periods while the underlying cause of airway obstruction is either treated or natural resolution is awaited (usually by growth). To enable these children to enjoy a relatively normal family environment despite a tracheotomy, it is desirable that they should be managed at home for at least part of the time. For the past 8 years we have routinely used soft polyvinyl chloride paediatric tracheotomy tubes (Shiley) in our patients. These tubes have proved to be relatively resistant to obstruction with secretions and are changed at 1- to 2-week intervals. They can be modified by making a series of three to four 2-mm through-and-through fenestrations around the shoulder in order to improve speech production and facilitate decannulation. Parents are tutored in tracheotomy care, which includes tube changing, humidification and suction. They are then permitted to take their child home from hospital when they are considered to be competent. Twenty-eight children (13 boys, 15 girls) with a mean age of 14.5 weeks (range 1-525 weeks) at the time of tracheotomy have been managed at home using this system. The median period of hospitalisation was 12 weeks (range 5-75 weeks), and the median duration of home management was 94 weeks (range 13-394 weeks). Sixteen patients have been successfully decannulated, 11 remain cannulated and 1 died at home from sudden infant death syndrome. Despite supportive measures, the majority of the children developed intermittent chest infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety and immunogenicity of ERA strain of rabies virus propagated in a BHK-21 cell line

The ERA strain of rabies virus was propagated in a baby hamster kidney cell line (BHK-21/C13). The viral titer was 10(1.8) tissue culture infective doses (TCID) higher than that of commercial ERA vaccine. The ERA/BHK-21 vaccine in baits retained titers of 10(6.3) to 10(6.4), TCID when subjected to daily temperature fluctuations from 9 degrees C to 24 degrees C for 21 days. This titer, according to a dose response in laboratory foxes, was still capable of immunizing up to 100% of foxes consuming a bait. The ERA/BHK-21 vaccine, when presented in baits, produced antibodies in 80 to 100% of dogs consuming more than one bait. Duration of immunity in foxes, from feeding the ERA strain rabies virus in baits, as determined by resistance to challenge with virulent virus, was at least 48 months. The vaccine strain retained some pathogenicity for nontarget species. In tests carried out on foxes, raccoons, dogs, cats and cattle, the vaccine did not cause vaccine-induced rabies. One of 14 skunks which consumed four baits developed vaccine-induced rabies, but virus could not be isolated from the salivary glands of this animal. The vaccine, when presented in baits, caused vaccine-induced rabies in 37% of laboratory mice, 3.4% of Microtus and 2.6% of Peromyscus species. Rabies virus could not be isolated from the salivary glands of rodents with vaccine-induced rabies. It was concluded that ERA virus propagated in BHK-21/C13 cells and incorporated in an acceptable bait produced a high titer, stable, immunogenic and safe vaccine for foxes.

Drug treatments for metastasis of the Lewis lung carcinoma: lack of correlation between inhibition of lung metastasis and survival

The abilities of the Eli Lilly compounds LY150310, LY189332, and LY135305 to inhibit spontaneous metastasis and to increase animal survival were evaluated. These compounds represent widely varied structures and were evaluated because they have been found to inhibit thromboxane synthetase, cyclooxygenase, and thrombin activation, respectively. These biochemical processes have been proposed in the literature as targets for antimetastatic drugs. The purpose of this investigation was twofold: (a) to compare the antimetastatic activities of the Eli Lilly compounds to those of the reference antimetastatic compounds nafazatrom and RA233, and (b) to examine the correlation between inhibition of spontaneous lung metastasis and survival. Spontaneous metastasis of the Lewis lung carcinoma was used to evaluate the antimetastatic activity of the compounds. In this model 5 x 10(5) tumor cells were implanted into the gastrocnemius muscle, the primary tumor was resected on Day 14, and metastatic lung lesions were counted on Day 25. Compounds were administered every 12 h on Days 5 through 19. Nafazatrom, LY150310, LY189332, and LY135305 were found to inhibit spontaneous lung metastasis in a dose-dependent manner. The ED50 values for the respective inhibitions with these compounds were 50, 0.5, 2, and 0.35 mg/kg/day; the respective therapeutic indexes (LD50/ED50) were 7, 180, 255, and 511. To evaluate the effect of nafazatrom, LY150310, LY189332, and LY135305 on animal survival, the compounds were given at maximally antimetastatic doses of 200, 60, 20, and 6 mg/kg/day, respectively. Two dosing schedules were used: (a) on Days 5 through 19 and (b) on Day 5 until death. Neither the median survival times nor the numbers of long-term survivors were significantly changed with any of the compounds at any dosing schedule. RA233, given to a maximally tolerated dose of 200 mg/kg/day on Day 5 until death, did not inhibit lung metastasis and did not increase median survival time. Postmortem examination of animals dosed with nafazatrom, LY150310, LY189332, and LY135305 showed complete inhibition in lung lesions and the appearance of lesions in the liver, kidney, spleen, and brain. The results of this investigation show that the effect a compound has on the number of metastatic lesions in a target organ may not be predictive of its effect on survival. To successfully translate laboratory data into the clinic, survival should be considered as a predictor of a compound's potential clinical utility.

Evaluation of the vomiting infant

This 12-month prospective study was undertaken to evaluate the cost, risk, and benefit of ultrasound followed by upper gastrointestinal series for the evaluation of the infant who vomits. Results suggest minimal morbidity from the upper gastrointestinal series, only a 33% reduction in the number of upper gastrointestinal series performed, and a 95% increase in cost if this imaging sequence is used. We conclude that the use of ultrasound for the initial evaluation of vomiting in infants substantially increases the cost with no meaningful decrease in morbidity and mortality.