The advantages of coated titanium implants prepared by radiofrequency sputtering from hydroxyapatite.

The method used to apply hydroxyapatite to implant surfaces may affect the thickness and ultimately the physical properties of the coating. This study investigated and compared the healing rates of bone around commercially pure titanium implants and titanium implants sputter-coated from a hydroxyapatite target. Forty-five sputter-coated implants and an equal number of noncoated titanium implants were placed into 15 partially edentulated dog mandibles. The implants were removed at three time periods and were evaluated mechanically and histologically. A multiple analysis of variance indicated that the interface bond strength was statistically greater (p less than 0.01) for the sputter-coated implants. Histologic analysis of the bone-implant interface demonstrated that coated implants had nearly twice the percentage of direct bone contact compared with noncoated implants. The results indicate that implants sputter-coated from a hydroxyapatite target will accelerate the healing of bone at the implant interface.

Comparison of expandable endotracheal stents in the treatment of surgically induced piglet tracheomalacia.

Present surgical alternatives for pediatric tracheobronchomalacia are limited and associated with many potentially undesirable complications. The feasibility of different intraluminal expandable endotracheal stents for the treatment of surgically induced tracheomalacia was analyzed in 27 piglets. A potentially fatal tracheomalacia was surgically created. Either a stainless steel "zig-zag" stent or a woven polymeric stent was then implanted. Tracheal patency, mucosal function, histopathologic respiratory tract changes, and effects of the stent on esophageal motility were evaluated over a 16-week period. Piglets with steel stents uniformly experienced intense inflammation leading to tracheal dysfunction and death. Piglets with polymeric stents experienced minimal respiratory symptoms. Expandable polymeric endotracheal stents alleviate surgically induced piglet tracheomalacia, were easy to insert, allowed for tracheal growth, and reduced the need for high-risk surgical procedures with prolonged ventilatory support.

Magnesium sulfate pharmacokinetics: pregnant Capra hircus model.

A comparison of standard clinical regimens for the administration of magnesium sulfate for treatment of preeclampsia was performed in the pregnant goat model. The regimen of intravenous or intramuscular load and intramuscular maintenance championed by Pritchard was found to yield higher maternal serum levels through the first 4 hours of treatment compared with intravenous load with intravenous maintenance therapy (p less than 0.05); however, neither regimen affected the concentration of magnesium ion in the cerebrospinal fluid. Urinary excretion of magnesium and passage into the amniotic fluid were also evaluated for each route of administration and neither accounted for the disparity in serum concentrations noted during the first 4 hours of magnesium therapy.

Studies of encephalitozoonosis in vervet monkeys (Cercopithecus pygerythrus) orally inoculated with spores of Encephalitozoon cuniculi isolated from dogs (Canis familiaris).

Encephlitozoonosis was induced in 35 of 38 vervet monkeys (Cercopithecus pygerythrus). They were either directly (orally) inoculated with Encephlitozoon cuniculi or indirectly exposed to this protozoan parasite. Cell-culture-grown spores of E. cuniculi, isolated from the kidneys of dogs with natural, fatal disease, were administered orally to 29 of these monkeys. Another 5 were exposed in utero by orally infecting pregnant females, and 3 were exposed to horizontal infection by nursing infected infants. Only one was given an intravenous inoculation of spores. The disease was induced in non-gravid and late-pregnant adults, immunocompetent infants, and in infants that were immunologically compromised by parenteral steroid administration, as well as in one infant that was immunologically immature because of its premature birth. The effects of age, dosage, post-inoculation (PI) interval, passage level of the parasite in cell culture and immunological status of the host were correlated with macroscopical and microscopical lesions. The experimentally induced infection was confirmed either by reisolation of the parasite in cell culture or by observation of spores in tissue sections. Both confirmatory methods were supported by serological examination. Reisolation of the organism in primary cell culture prepared from kidneys usually resulted in more frequent isolates and larger yields of spores from infants than from adult vervets. Infection with E. cuniculi invariably induced subclinical disease. Based on histology, lesions were minimal to moderately severe, depending on age, PI interval, and immunological status of the host. Alimentary tract infections were seen histologically as early as three days PI. Subsequently, infections resulted in detectable lesions most consistently in the liver, kidneys and brain. Lesions in these organs were generally granulomatous and were similar to those found in canine encephalitozoonosis. In addition, multifocal interstitial pneumonitis and myocarditis as well as vasculitis and perivasculitis were seen in other tissues and organs. Infants had more severe and more widespread lesions than adults. Although lesions and spores were still present in the brain of one immunocompetent infant 36 weeks after initial infection, the disease in immunocompetent infants and adults is thought to be self-limiting. However, infection may persist. Immunological depression favoured increased growth and multiplication of the organism, and resulted in detection of more spores within inflammatory lesions as well as more intracellular colonies of the organism that were free of inflammatory reaction.(ABSTRACT TRUNCATED AT 400 WORDS)

Observations on the pathology of experimental encephalitozoonosis in dogs.

Experimental transmission of canine encephalitozoonosis was effected by oral dosing of urine obtained from naturally diseased animals. Per os, intraperitoneal and intravenous routes were used to induce infection with tissue culture-grown Encephalitozoon spores which were initially isolated from the kidney of a dog with terminal disease. The infection was confirmed by a rise in the indirect immunofluorescent antibody titres, the lesions found in infected dogs and isolation of the parasite in tissue culture from an infected and immunosuppressed dog. The experimentally induced disease was invariably subclinical but the histopathological changes were similar although milder than those found in fatal natural disease. The kidney appears to be the target organ and chronic interstitial nephritis develops regularly.

Effect of folinic acid on the capacity of trimethoprim-sulfamethoxazole to prevent and treat Pneumocystis carinii pneumonia in rats.

Daily administration of 1 mg of folinic acid to immunosuppressed rats with incipient or established Pneumocystis carinii pneumonia did not impair the capacity of trimethoprim-sulfamethoxazole to either prevent or treat this disease. These observations constitute the first experimental support for the use of folinic acid to prevent or control cytopenias that occur in patients with Pneumocystis carinii pneumonia who are under trimethoprim-sulfamethoxazole treatment.

Trapping, care, and laboratory management of the silvered leaf monkey (Presbytis cristatus).

The silvered leaf monkey (Presbytis cristatus) from South Kalimantan ( Borneo ), Indonesia is a natural host for a variety of filarial nematodes including Brugia malayi and Wuchereria kalimantani . Experimental studies show that it is host for W. bancrofti, a filarial nematode causing elephantiasis in man. Presbytis cristatus is a gregarious primate of primary and secondary forests, roaming in troops of 20-30 members. Primarily a fruit and leaf eater under natural conditions, this monkey can adapt to a laboratory diet of commercial monkey chow supplemented with fruits and vegetables. Troops, led by an alpha male, immediately respond to protect their young during stressful or dangerous situations. Infants are born singly and are bright orange. Transition to the adult grey and black coloration begins three to five months after birth. Silvered leaf monkeys can be readily trapped. Initially they are aggressive and will attack but become tractable several days after capture. Reaching upward is an important feeding behavior of the silvered leaf monkey and they will not feed from the floor of the cage. In the laboratory they are nonaggressive and lend themselves to various procedures such as blood drawing and examination. Silvered leaf monkeys travel well in commercial animal transport cages. In the United Stages they are not an endangered species and can be readily imported. In Indonesia they are not protected by law and can be exported.

Experimental infection of warthos (Phacochoerus aethiopicus) with African swine fever virus.

Although there were no obvious signs of illness following experimental infection of young warthog with African swine fever virus, the animals developed viraemias between 10(2,4) and 10(3,6) HD50/ml within the first week of infection, and virus concentrations in a number of lymphatic tissues attained high levels (greater than or equal to 10(6) HD50/g). Unlike in blood, and to some extent in the spleen, virus titres in lymph nodes did not decline appreciable during the 33-day observation period, since at the end of the period lymphatic tissues from 2 warthog were still infectious for domestic pigs to which these tissues were fed.

The prevalence of Encephalitozoon antibodies in dogs and an evaluation of the indirect fluorescent antibody test.

Fifteen dogs which were serologically negative to the IFA test against Encephalitozoon developed antibodies in their sera following experimental infection. Six other dogs which were not tested prior to infection had titres to Encephalitozoon after experimental infection. In a sequential study in four dogs, antibodies first appeared between 32 and 39 days after infection. These results show that the IFA test would be suitable for epidemiological studies. Fifty serum samples collected from two kennels in which encephalitozoonosis had been confirmed showed an IFA test positive prevalence rate of 70%. In 220 serum samples submitted for various clinial pathological examinations the prevalence rate of antibodies to Ebcephalitozoon was 18%.

Canine encephalitozoonosis in kennels and the isolation of Encephalitozoon in tissue culture.

The protozoan Encephalitozoon was isolated in primary kidney cultures from dogs originating from three separate outbreaks of encephalitozoonosis in kennels. The disease was characterized by a fading syndrome in young puppies with nervous signs developing in some cases. It was not possible to reproduce the clinical disease with cultured organisms in either normal dogs or dogs immunosuppressed with methylprednisolone. The organisms were, however, reisolated in primary culture from two immunosuppressed dogs but not from other experimentally infected dogs. The freezing of Encephalitozoon organisms in liquid nitrogen is described.

African swine fever: pathogenicity and immunogenicity of two non-haemadsorbing viruses.

The virulence of 2 non-haemadsorbing African swine fever virus isolates were compared with 2 haemodsorbing viruses. While 3 of these isolates usually produced acute death in pigs, 1 non-haemadsorbing virus caused either a fatal infection with an extended course, or few or no obvious signs of infection. Pigs that survived infection with the latter virus were resistant to the lethal effects of the other 3 strains as well as to a pool of 7 isolates made from Ornithodorus porcinus porcinus (senus Walton, 1964) and warthog obtained in the Northern Transvaal.

Canine encephalitozoonosis in South Africa.

Clinical, clinicopathological macroscopical and histopathological findings, as well as electron microscopic and cultural confirmation, in twelve natural cases of canine encephalitozoonosis are described, eleven of these under one year of age. Nervous symptoms, including blindness, retarded growth rate and nephritis are prominent clinical signs. The macroscopic findings and histopathology proved of great help in the diagnosis of the disease even in chronic cases. The organism was cultured and some distinguishing electron microscopical features between Encephalitozoon and Nosema are discussed. A transmission experiment confirmed the diagnosis. The results are compared with the reported cases in dogs and Blue Foxes (Alopex lagopus).

Light and electron microscopical studies on canine encephalitozoonosis: cerebral vasculitis.

Brain lesions in 2 natural cases of canine encephalitozoonosis were studied by light and electron microscopy. Granulomatous reactions, associated with small vessels and capillaries, partly originated from extensive perithelial cell proliferation which ultimately produced the epithelioid cell component. Diffuse glial reactions apparently occurred in relation to the vasculitis. Lymphoid cells infiltrated the epithelioid and glial cell inflammation. Encephalitozoon in all its reproductive stages was identified as the aetiological agent, and ultrastructurally differentiated from Nosema on the basis that a single nucleus was observed. Viable organisms were present only within endothelial cells. Macrophages containing dead spores were usually seen around parasitized vessels and, less frequently, in the neuropil. Organisms, whether viable or non-viable, were never seen extracellularly at the ultrastructural level. Selected histochemical stains and electron microscopy were used to differentiate between viable and non-viable spores. Vasculitis is demonstrated as the underlying lesion of canine encephalitozoonosis affecting the brain and is suggested to be the basic factor in the pathogenesis of this disease.

Some infectious diseases of wild vervet monkeys (Cercopithecus aethiops pygerythrus) in South Africa.

Our surveys indicate that nearly all batches of vervet monkeys arriving at the National Institute for Virology from various areas of South Africa, are infected with foamy viruses and there is evidence that intra-urterine infection also occurs. Monkeys from certain areas of South Africa are apparently infected with the protozoal parasite Entopolypoides macaci in a sub-clinical state which becomes active when the monkeys are splenectomised. Serological studies indicate that infections with schistosomes, tick-bite fever (Rickettsia conori), chlamydsiae and occasionally by leptospirae, occur in monkeys in the Kruger National Park. Complement fixation tests for antibodies to R. mooseri and R. prowazeki were also sometimes positive; a finding of doubtful importance. There was a high percentage with positive antibody tests to chikungunya virus in a certain age group suggesting that there had been an outbreak of this disease in the Kruger Park in the late summer and autumn of 1976. This coincided with a human outbreak. Large numbers of vervet and baboon sera were tested for antibodies against SA 12 virus, a polyoma virus. A high percentage of baboons but only a small number of monkeys was found to be positive and it is concluded that SA 12 is probably a baboon virus which is occasionally transmitted to monkeys by contact. It is pointed out that these studies only indicate diseases from which monkeys recover and they do not indicate prevalence of severe disease causing grave illness or death.

Observations on the pathology of canine microsporidiosis.

The available literature on canine microsporidiosis indicates that this disease, primarily of young dogs, is a distinct clinicopathological entity. It has been confused with canine distemper and rabies, and must be differentiated from toxoplasmosis. Information available on the spectrum of pathological change associated with this disease is incomplete but a distinct pattern emerges from a study of the reports. The aetiological agent appears to have a predilection for the central nervous system and kidneys, but other tissues and organs, and especially the liver, may also be infected. Vasculitis and perivasculitis, which may include fibrinoid necrosis, seem to be a basic lesion. Cellular inflammation ranges from polymorphonuclear leukocyte infiltration in areas of necrosis to focal granulomas. There may be no cellular reaction to compact groups of organisms. Histopathological and ultrastructural studies of this case augment our knowledge of the pathological changes seen with canine microsporidiosis.