Evaluation of Ti/Al alloy coated with biogenic hydroxyapatite as an implant device in dogs' femur bones.

The main target of the present research was a full assessment of the toxicity effects and biocompatibility of a Ti/Al-alloy device coated with biogenic hydroxyapatite (bHA) when implanted in dogs in comparison with those of an uncoated Ti/Al-alloy device. The coating of the alloy was carried out using controlled high-velocity suspension flame spray (HVSFS) technique. Both coated and uncoated devices were implanted in dogs' femur bones for different time periods (45 days and 90 days). Bone-formation ability and healing were followed up, and blood analysis was performed, at Time zero (immediately post surgery), and then at 3 days, 45 days, and 90 days post surgery. Bone mineral density checks, radiological scans of the femur bone, and histological analysis were also conducted. The in-vivo study results proved that implantation of a device made from bHA-coated Ti/Al alloy in dogs' femur bones is completely safe. This is due to the high osteoconductivity of the coated alloy, which enables the formation of new bone and a full connection between new and original bone material. At 90 days post surgery, the coated alloy had been completely digested within the original bone; thus, it appeared as a part of the femur bone and not as a foreign body. Both the scanning electron microscopy with energy-dispersive X-ray and histology analysis findings affirmed the results. Furthermore, the blood tests indicated no toxicity effects during the 90 days of implantation.

High velocity suspension flame spraying (HVSFS) of metal doped bioceramic coatings.

•Bioceramic coatings doped with metals for antibacterial effect.•Combination of suspension and precursor flame spraying.•Successful deposition of submicron metallic particles in bioceramic matrix.

Microstructure and in vitro behaviour of 45S5 bioglass coatings deposited by high velocity suspension flame spraying (HVSFS).

The high-velocity suspension flame spraying technique (HVSFS) was employed in order to deposit 45S5 bioactive glass coatings onto titanium substrates, using a suspension of micron-sized glass powders dispersed in a water + isopropanol mixture as feedstock. By modifying the process parameters, five coatings with different thickness and porosity were obtained. The coatings were entirely glassy but exhibited a through-thickness microstructural gradient, as the deposition mechanisms of the glass droplets changed at every torch cycle because of the increase in the system temperature during spraying. After soaking in simulated body fluid, all of the coatings were soon covered by a layer of hydroxyapatite; furthermore, the coatings exhibited no cytotoxicity and human osteosarcoma cells could adhere and proliferate well onto their surfaces. HVSFS-deposited 45S5 bioglass coatings are therefore highly bioactive and have potentials as replacement of conventional hydroxyapatite in order to favour osseointegration of dental and prosthetic implants.

Detection of Moraxella bovis antibodies in the SIgA, IgG, and IgM classes of immunoglobulin in bovine lacrimal secretions by an indirect fluorescent antibody test.

The relationship between clinical infectious bovine keratoconjunctivitis (IBK) and Moraxella bovis antibodies was evaluated in a herd of calves during one summer. The detection and the distribution of antibody response in lacrimal secretions of beef calves to natural exposure of M bovis were determined by an indirect fluorescent antibody test. Three classes of immunoglobulins--secretory IgA, IgM, and IgG--were monitored in lacrimal secretions over a 5-month period when IBK was enzootic in the herd. The 3 classes of antibody to M bovis were detected in all but 2 calves at the start of the monitoring, and the highest and most persistent M bovis antibody titers were in the IgG immunoglobulin class, and less so in IgM and secretory IgA classes. The specific antibodies present in the lacrimal secretions did not prevent the development of clinical IBK in the calves.

Detection of Moraxella bovis antibodies in infectious bovine keratoconjunctivitis by a passive hemagglutination test.

A passive hemagglutination test was developed to detect antibody response to Moraxella bovis in tears. Tannic acid-treated sheep erythrocytes were sensitized with sonicated antigen prepared from M bovis cultures. The test was found to be a relatively simple, specific, and reliable procedure for titrating antibodies in lacrimal secretions. The hemagglutination test could be a valuable method for seroepizootiologic investigation of infectious bovine keratoconjunctivitis.

Bacteriologic and vaccination studies in a field epizootic of infectious bovine keratoconjunctivitis in calves.

Infectious bovine keratoconjunctivitis (IBK) was enzootic in the beef cattle herds at Dixon Springs Agricultural Center, University of Illinois. The development of nonhemolytic and hemolytic Moraxella bovis flora in the eyes of 48 calves in a closed cow-calf herd was monitored from late May to October, 1972. The incidence of clinical IBK was recorded each week. In late May, nonhemolytic M bovis was isolated from 26% of calf eyes. The peak incidence of IBK was observed in early September, with 26% of the eyes affected. At that time, nonhemolytic M bovis was isolated from 10% of the eyes, and hemolytic M bovis from 58%. By late October, nonhemolytic M bovis was isolated from 25% of the eyes, and hemolytic M bovis from only 4%. In an attempt to increase the resistance of ocular tissue, 19 calves were vaccinated in each third eyelid with 0.5 ml of an autogenous M bovis bacterin in late May. Vaccination did not provide practical protection against the establishment of hemolytic M bovis in the eyes nor the development of clinical IBK. However, at the peak incidence of IBK, hemolytic M bovis was isolated from the eyes of 48% of vaccinated calves and 73% of nonvaccinated calves; clinical IBK was present in 21% of the eyes of vaccinated calves and 29% of nonvaccinated calves. In evaluating the in vitro proteolytic potential of M bovis isolates, 83 hemolytic and 5 nonhemolytic isolates peptonized litmus milk; 176 nonhemolytic isolates did not peptonize litmus milk. Hemolytic M bovis isolates were more pathogenic for mice than were nonhemolytic isolates. Of 60 mice, 53 (88%) died in 1 to 3 hours after intraperitoneal inoculation of hemolytic isolates; 8 of 32 (25%) mice died in 5 to 15 hours after inoculation of nonhemolytic isolates. Hemolytic M bovis isolates produced testicular swelling and scrotal necrosis after inoculation into the scrotal sac of rabbits; nonhemolytic isolates produced only mild transient testicular swelling.

Immunity to leptospirosis: renal changes in vaccinated cattle given challenge inoculum.

Resistance to renal leptospirosis was demonstrated in cattle vaccinated with Leptospira interrogans serotype pomona bacterin. Fewer vaccinated cattle given challenge inoculum of virulent serotype pomona leptospires 12 months after vaccination had kidneys with gross focal lesions in the cortex than did nonvaccinated controls. Histopathologic changes characteristically associated with renal leptospirosis occurred less frequently and renal tissue damage was less severe in vaccinated cattle than in nonvaccinated controls. The isolation of serotype pomona from only 1 of 29 vaccinated cattle, compared to 7 isolations from 11 nonvaccinated cattle, at 26 days after challenge inoculum was given, indicated that mild renal infection occurred only infrequently in vaccinated cattle. It appeared that challenge inoculation of vaccinated cattle with virulent serotype pomona leptospires stimulated an accelerated secondary immune response in which immunity limited the multiplication of leptospires in the kidney.

Immunity to leptospirosis: Leptospira interrogans serotype pomona bacterins in cattle.

Immunity to renal leptospirosis was demonstrated in cattle vaccinated with Leptospira interrogans serotype pomona. Vaccinated cattle, challenge inoculated with virulent L interrogans serotype pomona organisms 12 months after vaccination, were resistant to renal infection; similarly inoculated, but nonvaccinated, cattle were susceptible to renal infection. Relationship was demonstrated between immunity induced in vaccinated cattle and that induced in hamsters vaccinated with a dilution of the same bacterin and later inoculated with virulent L interrogans serotype pomona organisms.