Highly stable water dispersible calix[4]pyrrole octa-hydrazide protected gold nanoparticles as colorimetric and fluorometric chemosensors for selective signaling of Co(II) ions.

Water dispersible stable gold nanoparticles (AuNps) have been synthesized by using calix[4]pyrrole octa-hydrazide (CPOH) as a reducing as well as stabilizing agent. CPOH-AuNps have been characterized by surface plasmon resonance, particle size analyzer and transmission electron microscopy. CPOH-AuNps are water dispersible, highly stable for more than 150 days at neutral pH with a size of less than 10nm and zeta potential of 15±2 MeV. Ion sensing property of CPOH-AuNps has been investigated for various metal ions Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Hg(II), Co(II) and Cu(II) by colorimetry and spectrofluorimetry. Among all the metal ions investigated, only Co(II) ions gives sharp colour change from ruby red to blue and is easily detectable by naked-eye. CPOH-AuNps being fluorescent in nature also shows great sensitivity and selectivity for Co(II) ions. Co(II) ions can be selectively detected at very low concentration level of 1 nM in a facile way of fluorescence quenching.

Cellular inflammatory response in the lungs of calves exposed to bovine viral diarrhea virus, Mycoplasma bovis, and Pasteurella haemolytica.

Three, 5, or 7 days after inoculation with bovine viral diarrhea (BVD) virus (n = 12) or Mycoplasma bovis (n = 12), groups of calves were exposed to aerosols of Pasteurella haemolytica and were euthanatized 4 hours later. Histologic lesions in the lungs and the ratios of neutrophils to alveolar macrophages, collected by bronchoalveolar lavage, were compared with those of clinically healthy calves (n = 8) and calves inoculated with BVD virus only (n = 4), M bovis only (n = 4), or P haemolytica only (n = 2). Inoculation with BVD virus or M bovis did not have a significant (P greater than 0.05) effect on the neutrophil/macrophage ratio in the bronchoalveolar lavage. Aerosol exposure to P haemolytica induced a marked and significant (P less than 0.01) change in the neutrophil/macrophage ratio (from less than 1:9 to greater than 9:1). The reversed neutrophil/macrophage ratio in calves exposed to P haemolytica correlated well with the histologic changes in which small bronchi and bronchioles were plugged with purulent exudate. Inoculation with BVD virus did not induce gross or microscopic lesions in the lungs. Inoculation with M bovis resulted in a severe peribronchial lymphoid hyperplasia with mild exudation of neutrophils and macrophages into the cranioventral parts of the lungs.

Exposure of calves to aerosols of parainfluenza-3 virus and Pasteurella haemolytica.

The present study was undertaken to investigate whether sequential exposure to aerosols of parainfluenza-3 virus followed by Pasteurella haemolytica, or P. haemolytica followed by parainfluenza-3 virus, could lead to the production of pulmonary lesions in conventionally-raised calves. Twenty male calves with low serum antibody titres to both organisms were placed in five equal groups. Synergism of parainfluenza-3 virus and P. haemolytica was not demonstrated in any of the sequentially infected groups and pulmonary lesions were mild in all challenged calves. Clinical signs of disease were not present after exposure to parainfluenza-3 virus although the virus was repeatedly isolated from nasal secretions of all inoculated calves. Exposure to P. haemolytica produced a transient response which consisted of increased rectal temperatures and respiratory rates, with a mild neutrophilic leukocytosis and a mild left shift present six hours postinoculation and returning to normal within 24 hours. Results from this study suggest, although do not confirm, that reduced pulmonary clearance of inhaled P. haemolytica in parainfluenza-3 virus infected calves does not necessarily lead to production of severe pulmonary lesions and that previous exposure to aerosols of P. haemolytica may not enhance secondary parainfluenza-3 virus infection.

The pulmonary clearance of Pasteurella haemolytica in calves infected with bovine virus diarrhea or Mycoplasma bovis.

Based on current literature which commonly associates bovine virus diarrhea virus and Mycoplasma bovis with "pneumonic pasteurellosis," an investigation was conducted into the effect of these two pathogens on the capacity of bovine lung to clear inhaled Pasteurella haemolytica. There was no significant effect (p less than 0.05) of either bovine virus diarrhea virus or M. bovis on the mean clearance rate of P. haemolytica, nor did the time interval of three, five or seven days between the first inoculation and exposure to P. haemolytica and adversely affect the lung clearance rates. However, it was found that the left lungs and a higher bacterial retention (p less than 0.05) than the right lungs.

The pulmonary clearance of Pasteurella haemolytica in calves given Corynebacterium parvum and infected with parainfluenza-3 virus.

Four control calves were aerosolized with parainfluenza-3 and one week later with Pasteurella haemolytica. Three calves were given Corynebacterium parvum at a dose of 15 mg/m2 body surface area, infected with parainfluenza-3 virus one week later, and aerosolized with P. haemolytica two weeks after C. parvum injection. All calves were killed four hours after P. haemolytica exposure and the bacterial retention in the lung was determined. Parainfluenza-3 viral infection did not exert any suppressive effect on pulmonary clearance of P. haemolytica in six out of seven calves used. However, the bacterial colony counts in the lungs of control calves were higher (P less than 0.05) than those in calves given C. parvum. Hence, C. parvum appeared to enhance bacterial clearance. Despite the marked influx of neutrophils into the lungs after the bacterial inoculation, the neutrophil:macrophage ratio in lavage samples was less in calves given C. parvum than in the control calves. The alveolar macrophages in C. parvum treated calves were generally larger but did not differ significantly (P less than 0.05) from those in the controls. There was no significant (P less than 0.05) correlation between the percentages of alveolar macrophages and the bacterial clearance. In calves given C. parvum, bacterial clearance was enhanced in those calves which had larger macrophages.

Factors associated with mortality in feedlot cattle: the Bruce County Beef Cattle Project.

The design of and the analysis of data from the Bruch County Beef Cattle Project, particularity the field study, are presented and discussed. A major value of the study may lie in its ability to relate laboratory findings to events in the field. The factor most strongly related to mortality was ration, with cattle on hay based rations having a much lower mortality on average than cattle on corn based rations. In general, management activities associated with growing cattle (as opposed to fattening) over the first winter were sparing for mortality. Groups of cattle given prophylactic vaccines or drugs within two days of arrival tended to experience higher mortality (not statistically higher) than those cattle not receiving those measures, or cattle groups recieving the same prophylactics more than 48 hours after arrival. However, these results require validation in the remaining years of the study. Fibrinous pneumonia was the most frequent diagnosis in the calves on postmortem examination.

Interferon, antibody responses and protection induced by an intranasal infectious bovine rhinotracheitis vaccine.

The interferon and antibody response induced by an intranasal infectious bovine rhinotracheitis vaccine was followed in 22 calves over a nine month period and the ability of these vaccinated calves to withstand challenge with virulent infectious bovine rhinotracheitis virus was assessed. Interferon was detected two to three days post-vaccination and disappeared by the tenth day. Nasal and serum antibodies appeared by day 7 and persisted for nine months. The calves challenged three days postvaccination came down with disease typical of infectious bovine rhinotracheitis, whereas calves challenged three weeks, three months or nine months postvaccination resisted infection.

A study of two species of fish inoculated with spruce budworm nuclear polyhedrosis virus.

Preliminary studies conducted on rainbow trout (Salmo gairdneri) and white suckers (Castostomus commersoni) exposed to spruce budworm nuclear polyhedrosis virus revealed minor histopathologic changes in various organs of each fish which were interpreted as not being significant. However, an evaluation (mean values) of the total changes in groups of fish suggested that a relationship may exist in the suckers exposed to either purified polyhedra or virions. A more extensive and definitive study must be done before any conclusions are warranted.

The pulmonary clearance of Pasteurella hemolytica in calves infected with bovine parainfluenza-3 virus.

The purpose of this study was to determine if parainfluenza-3 virus in calves interfered with normal pulmonary bacterial clearance. Three groups (A, B and C) of four calves each were exposed to an aerosol of parainfluenza-3 virus. Three days later the four hour pulmonary clearance of Pasteurella hemolytica was determined on the first group (A), seven days later on the second (B) and 11 days later on the third (C). Group A had a mean pulmonary bacterial retention of 3.6 +/- 3.5%. Group B was 83.1 +/- 35.9% and Group C was 41.2 +/- 30.9%. The results demonstrate that parainfluenza-3 virus interfered with the pulmonary bacterial clearance of Pasteurella hemolytica particularly on day 7 and also on day 11 but not on day 3. This inhibition of pulmonary clearance caused by the virus may be a key factor in the pathogenesis of pneumonic pasteurellosis. Histological examination of the lungs did not demonstrate a correlation between pulmonary retention of bacteria and the development of pathological changes.

Investigation of factors of probable significance in the pathogenesis of pneumonic pasteurellosis in cattle.

Six groups of ten beef calves six to eight months of age were shipped from western Canada and observed untreated for one week after arrival. The following parameters were measured daily: body temperature, plasma fibrinogen, nasal bacterial mean colony counts of Pasteurella hemolytica and Pasteurella multocida, total and differential leukoyte counts, packed cell volumes and the following, twice during the week: serum and nasal antibody titres to P. hemolytica and parainfluenza-3 virus. The lungs from 44 of the calves were obtained at post mortem and given a numerical score based on the degree of pneumonia present. Animals were designated SICK and WELL according to body temperature and plasma fibrinogen. The SICK animals had higher nasal mean colony counts of P. hemolytica than the WELL animals. The SICK animals had lower levels of serum antibody to P. hemolytica than the WELL on day 1 but had a greater rise in titre over the week than did the WELL animals. Both groups were similar with regard to serum antibody to parainfluenza-3 virus and there was little change in these titres. The SICK animals had a much greater degree of pneumonia than the WELL. The values of some of the parameters were combined with the data of previously studied animals in order to provide a comparison of SICK and WELL with larger numbers of animals.

The effect of edema, hydrocortisone acetate, concurrent viral infection and immunization on the clearance of Pasteurella hemolytica from the bovine lung.

The influence of pulmonary edema, hydrocortisone, immunization against Pasteurella hemolytica and concurrent infection with parainfluenza-3 virus upon pulmonary clearance of aerosolized P. hemolytica was studied in 31 calves. Following the various treatments calves were challenged with an aerosol of P. hemolytica. One control calf was killed immediately after the aerosol and the numbers of bacteria in the lung taken as 100%. Two calves were killed four hours after challenge and the numbers of bacteria in the lungs were compared to the 100% of the control calf. The result was the percentage clearance of bacteria at four hours. PULMONARY EDEMA WAS INDUCED BY THREE DIFFERENT METHODS: by an aerosol of histamine, by intravenous injection of endotoxin and by intravenous injection of croton oil emulsion. The edema impaired the clearance of P. hemolytica, which was reflected in high numbers of P. hemolytica present in the lungs at four hours after challenge: 260% after histamine, 300% and 400% after endotoxin and 92% after croton oil. SIX DAYS OF TREATMENT OF FOUR CALVES WITH HIGH DOSES OF HYDROCORTISONE ACETATE PRODUCED INCONSISTENT RESULTS: two calves treated with a higher daily dose (36 mg/kg) had normal clearance whereas two calves treated with a lower dose had pulmonary edema and displayed lowered clearance with 111% and 31% respectively of P. hemolytica retained in the lungs four hours after challenge. Immunization of calves by three different methods, a subcutaneously injected bacterin of P. hemolytica (2 calves), single aerosol (2 calves) and four aerosols (4 calves) of live P. hemolytica was reflected in an accelerated pulmonary clearance of P. hemolytica (with a mean of 1.55% of bacteria retained at four hours). Concurrent infection with parainfluenza-3 virus did not lower the clearance of P. hemolytica in the lungs of 12 calves over 15 days except on the first day following the exposure to parainfluenza-3 virus. These calves had hemagglutinating antibodies against P. hemolytica before exposure.

Pneumonic pasteurellosis of cattle: microbiology and immunology.

Pasteurellosis was investigated under natural conditions by comparing bacterial and viral nasal flora and levels of bacterial and viral antibody in sera and nasal secretions between animals sick with the disease and those that remained well. The animals were classified sick or well on the basis of the levels of body temperature and plasma fibrinogen. The most significant feature of the bacterial flora was the higher frequency of isolation and the numbers of Past. hemolytica in the nasal flora in the first two weeks after shipment. As indicated by the number of animals with serum antibody to PI-3 virus, infection with this virus was active in both sick and well animals, and serologically, the incidence of infection was higher in animals that remained well. Nasal antibody to PI-3 virus was slightly lower in incidence than serum antibody. Examination of untreated fatal cases and animals killed during the experiment suggests that in some animals there may be a relationship between the high numbers of a bacterial species in the nasal passage and infection by that organism in the lung.