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The cell morphology, the number of flagella, the occurrence of periplasmic fibrils and ultrastructural structures of five groups of cultured canine gastric Helicobacter spp. were compared. The study included four strains of Helicobacter felis, four strains of Helicobacter bizzozeronii, one strain of 'Flexispira', six strains of an unnamed spiral organism 2 and one strain of an unnamed spiral organism 3 which were isolated from gastric biopsies. Cultures were studied with negative staining, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Bacterial dimensions were measured from the negative staining samples and values were tested with ANOVA and Bonferroni tests. The organisms studied differed from each other morphologically. H. felis was a slightly spiraled organism with periplasmic fibrils. 'Flexispira' was a thin and straight organism with periplasmic fibrils. H. bizzozeronii was a tightly spiraled organism. Spiral organism 2 was loosely spiraled and thicker than the other organisms. Spiral organism 3 was a short curved rod having a single bipolar flagellum. The other species had multiple flagella. As a conclusion the canine gastric Helicobacter spp. can be differentiated from each other morphologically with an electron microscope. The morphological differences were mainly found in the structures involved in motility. The importance of the differences may lie in their impact on the colonization in a gastric mucous environment.

We carried out an immunohistological and morphological study on Pneumocystis carinii originating from the common shrew, Sorex araneus. Immunologic properties were studied by applying two commercially available immunofluorescence staining kits with differing developmental form specificity to a lung homogenate. The cyst form-specific staining kit reacted with cysts originating from S. araneus. Ultrastructurally this particular antigen epitope specifically deposited on the electron-lucent middle layer of the cyst pellicle. The immunohistochemical staining kit reacting with both cyst and trophozoite forms from human and rat origin did not react with any developmental forms of P. carinii originating from S. araneus. Both kits demonstrated P. carinii in the lung homogenate of a field vole, Microtus agrestis. In morphologic examination, the methenamine silver-stained cyst forms of P. carinii from S. araneus and from M. agrestis differed in size from each other and from those originating from laboratory rats. Ultrastructurally P. carinii from S. araneus did not differ from organisms of rat origin.

The effect of a single intraoperative injection of hyaluronan on intraocular pressure (IOP) and postsurgical tissue healing was evaluated on 18 rabbits with an aqueous drainage implant. During the follow-up period IOP was recorded and analysed. Furthermore, inflammatory reaction and appearance of the fibrous tissue around the implants were studied in histological sections. In both the hyaluronan and control groups the operation lowered the average IOP statistically significantly for the whole follow-up period when compared with preoperative values. From days 7 to 60 the mean IOP values of the hyaluronan injected eyes stayed at a lower level than in the control eyes, but with no statistical difference between the 2 groups. The connective tissue layer around the implants appeared less dense during the first 17 postoperative days in the sodium-hyaluronate group; in addition, the inflammatory cell reaction showed a tendency to remain acute longer.

Objective: Human immunodeficiency virus (HIV)-seropositive patients have frequently severe gingival inflammation and/or attachment loss. In addition many infectious diseases affect their periodontium with varying clinical manifestations. Matrix metalloproteinases seem to play a key role in physiological periodontal remodelling and pathological tissue destruction. The aim of the present study was to characterize the presence, molecular forms, cellular sources, activities, and relative amounts of fibroblast-type (matrix metalloproteinase [MMP]-1) and neutrophil (MMP-8) collagenases, as well as their potential activator stromelysin-I (MMP-3) and myeloperoxidase in saliva of HIV-seropositive patients at different phases of HIV-infection. HIV-seronegative, healthy, age-matched patients served as controls., Patients and Methods: Saliva samples were characterized by Western blotting using antibodies specific for MMP-1, MMP-3 and MMP-8. Interstitial collagenase activities were measured using quantitative sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis/laser densitometry assay. Myeloperoxidase was analysed using quantitative dot blotting., Results: Clinical and microbiological evaluation of HIV-seropositive patients' periodontium showed the presence of putative periodontopathogens ie Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Peptostreptococcus micros (Psm) and Campylobacter rectus (Cr) in their periodontal pockets. The amount of Candida increased with the severity of HIV-infection. Clinical and microbiological findings of HIV-seropositive patients suggested that they have a tendency to develop periodontal disease. Interstitial collagenase activities were found to be increased in saliva of different phases of HIV-infected patients compared to the controls. Independent of the phase of HIV-infection saliva samples contained pro- and active forms of MMP-1, -3 and -8 using Western blotting. Saliva samples from healthy controls were found to contain hardly any immunoreactivities for MMP-1 or MMP-8, but considerable amounts of MMP-3 were detected. Quantitative dot blotting demonstrated increased amounts of myeloperoxidase in HIV-patients' saliva relative to controls., Conclusion: The present results showed increased amounts of MMP-1, -3, -8 and myeloperoxidase in HIV-patients' saliva. MMP-1 and -8 may have been activated by MMP-3 and/or oxidants generated by myeloperoxidase. The increased amounts of MMPs and myeloperoxidase may reflect and directly participate in HIV-infection associated periodontitis.

Objectives: To investigate the role of complement cascade induced damage and protection against it in acute arthritides compared to rheumatoid arthritis and other chronic joint derangements., Methods: C3c, C9, and protectin (CD59) were examined by avidin-biotin-peroxidase complex staining., Results: Marked deposits of C3c and C9 were found in synovial vasculature and intercellular matrix of the lining in rheumatoid arthritis and in acute arthritides (including bacterial, reactive, and osteoarthritis flare up). Furthermore, protectin was not visible in synovial lining cells and was relatively weakly expressed in stromal and endothelial cells in rheumatoid arthritis; also in acute arthritides protectin expression was weak. In contrast, C3c and C9 deposits were not found in chronic conditions associated with degenerative diseases (osteoarthritis and osteochondritis dissecans) or mechanical causes (patellar luxation and a ruptured meniscus), in which also the protectin expression was prominent in synovial lining, endothelial and some stromal cells., Conclusions: Activation of the complement in rheumatoid arthritis and in acute arthritides seems to be associated with a decreased protection of synovial cells against cellular effects and lysis mediated by membrane attack complex.

The high incidence of pneumonia caused by Pneumocystis carinii in immunosuppressed patients makes it the most important parasite in non-tropical geographical regions. It has recently been shown to be a fungus, but several aspects of this organism are still poorly understood. A major question of clinical relevance is the nature of transmission and, thereby, the related problem of prevention. The mode of P. carinii transmission is thought to be air, but this is based on circumstantial evidence, the transmissive stage has not been identified. We attempted to capture P. carinii by filtration of air in the vicinity of cages containing P. carinii infected Wistar rats. Using nested polymerase chain reaction amplification of the thymidylate synthase gene to demonstrate P. carinii we were able to demonstrate P. carinii DNA on such filters. This strongly supports the suggested mechanism of transmission of Pneumocystis by means of airborne spores and suggests an approach to their isolation and characterization.

A total of 12 reindeer calves were divided into two groups and the volume densities of liver cytoplasmic structures were counted using TEM. The six animals in group 1 were allowed to graze freely while those in group 2 were kept in pens and fed with lichens. All of them had a negative energy balance and lost weight from November to April, group 1 by 14.9% and group 2 by 24.8%. In spite of the weight losses, no significant changes in volume densities occurred during the winter. Glycogen remained fairly steady and there was no fatty infiltration into the hepatocytes. The very low incidence of Golgi apparatus in the hepatocytes may have been due to the inhibition of protein and lipid synthesis during the winter. These results point to substantial adaptation to extreme environmental conditions. The animals in group 1 apparently moved about more, which may have caused a greater breakdown of glycogen, resulting in turn in a lower volume density of glycogen in January and March.

Our aim was to study histopathological changes in lung tissue at the light microscopic and ultrastructural level during recovery from immunosuppression and Pneumocystis carinii pneumonia. Male Wistar rats were immunosuppressed by per oral dexamethasone for 12 weeks to induce P. carinii pneumonia, after which dexamethasone was stopped. Recovery was monitored 1, 2 and 4 weeks after cessation of the immunosuppression. In immunosuppressed animals, CD4+ and CD8+ lymphocytes were both decreased in situ. CD8+ lymphocytes increased above control level at week one. Like CD8+ cells, the ED1+ macrophages increased rapidly in situ. This was accompanied by a progressively increasing migration (more transient for lymphocytes) of macrophages into bronchoalveolar fluid, associated with morphological signs of activation and phagocytosis and proliferation of type II pneumocytes. Bronchoalveolar lavage (BAL) fluid tumour necrosis factor-alpha (TNF-alpha) increased from subnormal levels to a 4 week peak, with an inverse correlation between TNF-alpha and cyst count (r = -0.626). Our observations suggest a sequence of changes characterized by an increase in CD4+ cells, accompanied by a more rapid and prolonged recruitment/activation of CD8+ cells, macrophages and type II pneumocytes.

Pneumocystis carinii has two developmental stages: the trophozoite and the cyst. The differential specificity of monoclonal antibodies SMoAb (cysts only) and CMoAb (cysts and trophozoites) was used to analyse the trophozoite-to-cyst (T: C) ratio during recovery from P. carinii pneumonia (PCP) in a dexamethasone model in Wistar rats. In tissue homogenates the cysts decreased from week 0 to week 4 (4.10 +/- 1.57 10(6)/g vs 0.069 +/- 0.021 10(6)/g, p < 0.001), whereas the trophozoites decreased much less, leading to a change in T: C ratio from week 0 and 1 (72 +/- 33 and 49 +/- 14, respectively) to week 2 and 4 (1752 +/- 652 and 1163 +/- 482, p < 0.001). A similar tendency was found in immunofluorescence-labelled histological samples quantitated with the VIDAS image analyser. These results demonstrate a hitherto unrecognized and significant change in T: C ratio during recovery from PCP. This change could not be monitored using bronchoalveolar fluid, probably due to adherence of the trophozoites to the alveolar wall. Changes in T: C ratio indicate that in particular the cyst form of P. carinii is sensitive to the host response mounted during recovery, and support the theory that trophozoites probably also multiply in an extracystic asexual fission.

Pneumocystis carinii pneumonia (PCP) is characterized by the formation of leaky alveoli and a foamy alveolar exudate. To induce PCP, male Wistar rats were immunosuppressed by oral dexamethasone treatment for 12 weeks, during which time all rats developed PCP. Bronchoalveolar lavage fluid (BALF) was analyzed at that time and at 1, 2, and 4 weeks after the cessation of dexamethasone treatment, during which time the rats were recovering from PCP and immunosuppression (and was compared with the BALF obtained from healthy control rats), for type IV collagenase, elastase, cathepsin G, and collagenase activities. Scores for 72-kDa (matrix metalloproteinase type [MMP-2]) and 92-kDa (MMP-9) type IV collagenase-gelatinase activities correlated with those for BALF macrophages (r = 0.58; P < 0.001) and neutrophils (r = 0.66; P < 0.001), respectively, suggesting that they may, in part, be derived from these cells. However, MMP-2 was constitutively expressed and may play a role in normal tissue remodeling. MMP-9 activity was highest in the group with PCP (1.8 +/- 0.37; P > 0.05), with a gradual decline (1.0 +/- 0.48 by week 4; P > 0.05) toward normal (0.67 +/- 0.42) during recovery, which suggests a role for it in tissue-destructive inflammatory events. In rats with PCP the endogenously active collagenase was present at high levels compared with those in healthy controls (2.6 +/- 0.69 versus 0.17 +/- 0.17, respectively; P < 0.01), but they returned to normal by week 4 of recovery (0.42 +/- 0.30; P > 0.05). Collagenase activity showed a correlation with cyst number (r = 0.57; P < 0.001). The BALF of rats with PCP also contained the serine proteinases, which may act as pro-MMP activators. Ultramorphology disclosed increased pinocytotic activities, subepithelial bleb formation, and degeneration and denudation of the basal lamina. These findings suggest that the increased activities of collagenases in BALF caused by the host response against P. carinii might contribute to leaky alveoli.

The ultrastructural immunolocalization of target antigens recognized by two monoclonal antibodies against Pneumocystis carinii was investigated using both human- and rat-derived organism. Labelling was seen using both cryo electron microscopy and postembedding in Epon after fixation in glutaraldehyde. The antibodies showed different host species- and developmental stage specificity. One of the antibodies reacted with the outer membrane of all developmental stages of human-derived but not rat-derived organisms, whereas the other reacted only with the cyst form. The distribution of the latter was similar to that reported for methenamine silver, a widely used cytochemical stain for the parasite, and reacted with both human- and rat-derived organisms. The antibodies described appear to be useful markers in studies on the differentiation of Pneumocystis carinii.

The prevalence of Pneumocystis carinii was compared in two species of shrews, Sorex araneus and Sorex caecutiens in Finnish Lapland. The overall prevalence of P. carinii in S. araneus was 70% and in S. caecutiens was 17%. The prevalence for S. araneus is the highest reported for wild animals. The interspecific differences in prevalence were significant for all sex and age groups except for adult males. Based on multiway contingency tables (log-linear models), there was no dependence between sex or age of S. araneus and occurrence of P. carinii. In individual S. araneus the intensity of P. carinii was not related to the total number of helminths or the number of helminth species, and no dependence was observed between the presence of P. carinii and various helminth species.

Pneumocystis carinii (PC) is an opportunistic pathogen which causes clinical disease in immunocompromised hosts. Three different staining protocols were employed to detect this organism in lung samples of corticosteroid treated voles in order to discover a suitable method for large-scale screening. The procedures employed were: Grocotts methenamine silver (GMS)-stained paraffin sections, toluidine blue O-stained impression smears, and methenamine-silver-stained frozen sections. GMS-stained paraffin sections were relatively easy to interpret and gave more positive results than the other methods. It seemed to be the satisfactory method for large-scale population analyses. An unexpected result was that methylprednisolone treatment did not induce in voles a similarly fatal pneumocystosis infection as occurred in rats. All infections found in voles were mild. This might be due to species-dependent differences in metabolizing methylprednisolone.

Feline immunodeficiency virus (FIV) was first isolated and identified in 1986. Since then it has been shown to have a worldwide distribution, and the infection generally appears to have reached a state of endemicity. This is the 1st study of FIV-prevalence in Finland. Serum samples of 196 free-roaming cats were tested for antibodies to FIV and FeLV antigens (Feline leukemia virus). With a combined enzyme-linked immunosorbent assay (ELISA), 13 of the cats (6.6%) turned out to be positive for FIV and 2 for FeLV (1.0%). Adult male cats in the capital area of Finland had a FIV prevalence of 24%, a relative proportion 4.7 times higher than that for females.

Toward the end of 1989 the largest private veterinary laboratory in Finland (Vet/lab) began using a commercial combined ELISA test for Feline Immunodeficiency Virus (FIV) antibodies and Feline Leukemia Virus (FeLV) antigens (Cite Combo). The overall proportion of FIV seropositive feline samples was 5% during the 22 month study period. The number of tests performed increased slowly while the positive test results decreased with time (7% in 1990 and 4% in 1991). The decrease in prevalence was assumed to reflect a change in the sample population rather than an actual change in the general cat population. There were more symptomatic and domestic cats tested in 1990 than 1991. The lower-risk groups in the second year of the study may simply be an indication that the cat owners became more aware of FIV and the motivation to send samples switched from the veterinarian's interest to diagnose the disease in a symptomatic cat to the owner's interest to survey their cats for possible FIV infection. In a multivariable analysis, breed, symptoms, age and sex were associated with the risk of FIV seropositivity. The risk increased faster with age in males than in females (i.e., the age effect was not constant between sexes). The cats with symptoms had a higher risk than those without symptoms and non-purebred cats were at a higher risk than purebred cats. FeLV infection was not associated with FIV.

Because of difficulties in in vitro cultivation, the basic Pneumocystis carinii studies have been carried out on animal models, mainly on rodents immunosuppressed by corticosteroids. Commonly used dexamethasone and methylprednisolone procedures were evaluated. The intensity of infection in rats was statistically significantly higher after 9 weeks' immunosuppression with methylprednisolone than with dexamethasone.

This communication describes the ultrastructure of the ependyma of the bovine area postrema. The polygonal cells possessed an abundant apical array of microvilli but were nonciliated with the exception of occasional cells at the periphery of the area, which had a central kinocilium. The low squamous cells contained moderate numbers of cytoplasmic organelles. The cells do not appear to be typically secretory, but may function in fluid exchange.

Early autolytic changes in rat heart muscle were quantified using electron microscopical morphometry. Five different time groups with five rats in each group were used. All the rats were anaesthetised, and the hearts of the rats in one group were fixed by perfusion. The other rats were decapitated, and immersion fixation of the hearts performed one minute, five minutes, 10 minutes or 25 minutes after the death of the animals. When compared to perfusion fixation, the first significant changes were seen in the five minute group. The volume densities of myofibrils and glycogen decreased and the volume density of mitochondria increased. These changes were partly due to a shortening of individual sarcomeres. A gradual shortening of the sarcomeres was seen in the one, five and 10 minute groups. Distinct I bands were frequently seen only in the perfusion group. In the mitochondria a decreased matrix density and a partial disorganisation of the cristae were evident in the five minute group. Swelling of individual mitochondria was seen in the 10 minute group, but the increase in size of individual mitochondria was significant in the 25 minute group. After death, morphological changes occur very rapidly in heart muscle cells. This must be taken into consideration when, for example, slaughterhouse material is prepared and interpreted in ultrastructural studies.

A latex agglutination test (LA) was compared with direct electron microscopy (EM) for detection of rotavirus infection in calves. A total of 375 samples from 62 calves were collected. Samples were taken when the calves were 1, 3, 5, 7, 10 and 20 days old and some scours samples were collected as well. Altogether 45/375 (12%) specimens were positive in LA and 10/375 (2.7%) were positive in EM. Samples positive in EM were also positive in LA. Out of the 62 calves studied 26/62 (42%) were positive in LA and 8/62 (13%) in EM. We found the LA very easy to perform, to be more sensitive than the EM method and probably a rather specific method for detection of rotavirus infection.