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Biomedical subjects

B Kristensen

Publications and source records attributed to B Kristensen.

106 records · Page 6Linked to original sources
PubMed1982

Immunological and pathological findings in demyelinating encephalitis associated with canine distemper virus infection.

Nine dogs with canine distemper encephalitis (CDE) were examined with immunological techniques including demonstration of antibodies against canine distemper virus (CDV) in the serum and against myelin basic protein (MBP) in serum and in CSF. Mitogen stimulation tests of lymphocytes were also done. The brains were examined pathologically and immunoglobulin and C3 were demonstrated in lesions by means of immunohistological techniques. Six dogs with acute CDE had none or low antibody levels against CDV or MBP, and there was no immunoglobulin in demyelinating lesions. Some of these dogs had depressed lymphocyte mitogen responses. Two dogs with chronic CDE showed recovery of lymphocyte mitogen responses. One of these had a significant antibody response against CDV and MBP in the serum. Both dogs with chronic CDE had very high antibody titers against MBP in the CSF and demyelinating lesions contained immunoglobulin. These results suggest that acute demyelination in CDE is probably due to some direct viral activity and that the progression of demyelination in chronic CDE is associated with a local immune response.

Animals↗
PubMed1982

Canine lymphocyte cultures in vitro: evaluation of peripheral blood lymphocyte response to mitogens.

Lymphocytes from dog peripheral blood have been stimulated in vitro with 3 different mitogens (Con A, PHA and PWM). Culture medium was RPMI 1640 enriched with either autologous plasma, fetal calf serum of a newly described defined serum substitute. In such cultures the number of surviving and activated cells was measured by cytofluorometry and the proliferation was assessed by thymidine incorporation. In unstimulated cultures, up to 70% of all cells had disappeared (died) during the first 42 hours of incubation, whereas the number of viable cells was reduced to 50-60% in mitogen stimulated cultures. Of the surviving lymphocytes, between 25-40% of the cells appeared to have an elevated RNA-content (activated or G1 cells). By comparison between thymidine incorporation and number of mitogen induced G1 cells, a very high correlation was found (r=0.92). However, the Slope of the regression line was much lower than expected. The low thymidine incorporation per activated cell was primarily related to the high cell death and a resulting dilution of tritiated thymidine. Indeed, preliminary results suggested that the same thymidine incorporation per G1b cells could be obtained if peripheral blood lymphocytes were washed immediately before pulsing as could be obtained with lymph node cells without washing.

Animals↗
PubMed1982

Technical aspects of low 3H-thymidine incorporation by mitogen stimulated canine peripheral blood lymphocytes in vitro.

The value of [3H]-thymidine incorporation as a measurement for mitogen induced proliferation of dog peripheral blood lymphocytes (PBL) has been examined. The cells were cultured in RPMI 1640, enriched with 10% autologous plasma for 48 hours at 37 degrees C, 5% CO2 and 95% relative humidity. Under these conditions a great variability in [3H]-thymidine incorporation was observed. By analysis of CPM and number of activated cells (G1), it was found that comparable number of G1 cells were generated in human and dog PBL. Also, the membrane transport of thymidine was very similar for lymphocytes of the two species. Nevertheless, a low [3H]-thymidine incorporation by dog PBL was frequently seen, and this phenomenon could be related to a release of soluble substance(s) within the cultures. When the cultured cells were washed and resuspended in fresh medium immediately before pulsing, the expected CPM per G1 cell could be obtained. Since it has been described in the literature that macrophages can produce cold thymidine in macrophage enriched lymphocyte cultures, the in vitro response of non-adherent dog PBL was analyzed. Mitogen stimulation of such non-adherent cells resulted in CPM per G1 cells very similar to those obtained with washed cells. Based on these data, it is suggested that the production of cold thymidine might be one of the technical problems related to cultures of lectin stimulated dog PBL in vitro and it should be taken into consideration, if [3H]-thymidine incorporation is used as the only measure of lymphocyte proliferation.

Adult↗
PubMed1981

Immunoglobulins in demyelinating lesions in canine distemper encephalitis. An immunohistological study.

The brains of 14 dogs with canine distemper encephalitis were examined with immunohistologic techniques to search for immunoglobulin in demyelinating lesions. Four types of lesions presumably representing a temporal sequence of lesion development were distinguished. Immunohistologic findings included immunoglobulin bearing lymphoid cells, amorphous Ig containing material, immunoglobulin bound to the tissue and immunoglobulin containing macrophages and astrocytes. The humoral immune response was absent or very minimal in acute lesions and very intense in chronic lesions. It was concluded that early demyelination in canine distemper encephalitis occurs in the absence of a local humoral immune response but that this response may aggravate and accelerate myelin destruction in the later stages of the disease.

Acute Disease↗
PubMed1981

Cell-mediated and humoral immune response in swine after vaccination and natural infection with Mycoplasma hyopneumoniae.

Litters of pigs were vaccinated with inactivated Mycoplasma hyopneumoniae organisms in Freund's complete adjuvant. The cell-mediated and humoral immune response following vaccination was investigated, and the protective effect of the induced immunity was assayed. The cell-mediated immune response to whole M hyopneumoniae organisms was determined as incorporation of tritiated thymidine, using a microculture system. After vaccination, detectable sensitization of peripheral blood lymphocytes was induced. The inoculations induced considerable antibody titers in the animals. The animals were challenged exposed by natural infection and protective effect of the cell-mediated or humoral response could not be detected.

Animals↗
PubMed1980

Growth medium constituents contaminating mycoplasma preparations and their role in the study of membrane glycoproteins in porcine mycoplasmas.

Several Mycoplasma and Acholeplasma species chosen at random and solubilized with sodium dodecyl sulphate showed a common periodic acid-Schiff positive band with an apparent molecular weight of about 64 000, when examined by polyacrylamide gel electrophoresis. Another more cathodic minor band was detected in M. hyopneumoniae and M. flocculare. The common periodic acid-Schiff positive band appeared when a precipitate of serum constituents of the uninoculated growth medium after incubation was examined. The minor band was identified as a serum glycoprotein contaminating mycoplasmas grown in the presence of swine serum. We draw attention to the compounds as a possible source of error in serological tests or in the lymphocyte stimulation response. After lithium diiodosalicylate solubilization and aqueous phenol extraction, polyacrylamide gel electrophoresis showed a periodic acid-Schiff positive band in membranes from M. hyopneumoniae (molecular weight 75 000) and M. hyorhinis (molecular weight 80 000), suggesting the presence of a membrane glycoprotein. Such a glycoprotein was absent from A. granularum. Since the common periodic acid-Schiff positive band was not extracted by aqueous phenol, this growth medium constituent did not contaminate the preparations of membrane glycoproteins. However, the minor band was present in glycoprotein preparations of M. hyopneumoniae grown in the presence of swine serum.

Acholeplasma↗
PubMed1980

Chronic canine distemper virus encephalitis in mature dogs.

Five dogs 2 to 8 years old with old dog encephalitis were compared to five other dogs, 4 to 8 1/2 years old, with prolonged multifocal demyelinating distemper encephalitis. The dogs with old dog encephalitis had a diffuse panencephalitis involving most areas of the central nervous system with relative sparing of the cerebellum. The clinical signs were related to the cortical and subcortical lesions. The other dogs had severe focal necrotizing lesions mostly in the cerebellum and in the vicinity of the fourth ventricle; clinical signs were related to brainstem and spinal cord lesions. Viral isolation attempts were unsuccessful in the dogs with old dog encephalitis. In two dogs with multifocal encephalitis, canine distemper virus was isolated in tissue culture. The differences in lesions, clinical signs and observations in vitro indicate differences in pathogenesis between old dog encephalitis and multifocal demyelinating distemper encephalitis although both diseases may be caused by the same agent.

Age Factors↗
PubMed1979

The effect of inhibitors on the oxygen kinetics of terminal oxidases of Acanthamoeba castellanii.

1. Respiration of growing cultures of Acanthamoeba castellanii is inhibited less than 60% by azide (35 mM); the respiration of early-exponential-phase cultures differs from that of late-exponential-phase cultures in being stimulated by up to 120% by low concentrations (less than 1 mM) of this inhibitor. Azide (0.5 mM) plus 1 mM-salicylhydroxamic acid gives 80% inhibition of respiration in early- or late-exponential-phase cultures. 2. Lineweaver-Burk plots of 1/v against 1/[O2] for growing and stationary-phase cultures give values of less than 1 muM for the apparent Km for oxygen. 3. These values are not significantly altered when determined in the presence of 1 mM-salicylhydroxamic acid. 4. Higher values (greater than 7 muM) for apparent Km values for oxygen were obtained in the presence of azide, which gives non-linear Lineweaver-Burk plots. 5. Competitive inhibition of respiration by CO occurs with Ki 2.4 muM. 6. The results are discussed in terms of the presence of three terminal oxidases in this organism, namely two oxidases with high affinities for oxygen (cytochrome c oxidase of the main phosphorylating electron-transport chain and the salicylhydroxamic acid-sensitive oxidase) and a third oxidase with a low affinity for oxygen, sensitive to inhibition by cyanide but not by azide or salicylhydroxamic acid. The relative contributions to oxygen utilization by these oxidases change during the growth of a batch culture.

Amoeba↗
PubMed1978

Immunofluorescence studies of canine distemper encephalitis on paraffin-embedded tissue.

A paraffin-embedding technique for fluorescent antibody studies of canine distemper encephalitis was developed. Specific fluorescence was demonstrated in all brain tissue from dogs with canine distemper, and when compared with tissue on cryostat sections, the paraffin-embedded tissue showed superior preservation of tissue architecture. The preservation of viral antigen was good, and the appearance of fluorescence in gray- and white-matter lesions was described. In gray matter, extensive fluorescence was found mainly in neurons; fluorescence in white matter was less extensive and was mainly associated with astrocytes.

Animals↗
PubMed1977

Observations on the distribution of canine distemper virus in the central nervous system of dogs with demyelinating encephalitis.

The distribution of canine distemper virus in the central nervous system was examined in 11 dogs with demyelinating encephalitis by the direct fluorescent antibody technique on paraffin sections of brain and spinal cord. In the grey matter there was a good correlation between the presence and severity of lesions and presence and amount of viral antigen. Large concentrations of virus were found in neurons and their processes. In most demyelinating lesions only small amounts of viral antigen were found, mostly located in astrocytes. The potential importance of the role of the astrocyte in demyelination in canine distemper virus infection is stressed.

Animals↗
PubMedDate not supplied

Clinical features and prognosis in young adults with infratentorial infarcts.

BACKGROUND AND PURPOSE: Many comprehensive descriptions of the clinical spectrum of infratentorial infarcts in elderly patients and with a retrospective design have been published. The aim of this study was to describe the clinical characteristics and prognosis in young patients with isolated infratentorial infarcts. METHODS: In a prospective series of 105 patients aged 18-44 years with cerebral infarction 24 had a brainstem or cerebellar infarction. The patient selection was validated in a population-based epidemiological survey. The patients were assessed acutely and at 4 and 12 months after onset. Extensive evaluation included CT and MRI scans, angiography, ultrasonic duplex scanning, transesophageal echocardiography and a chemistry panel including hematologic testing. The modified Rankin scale and NIH stroke scale were used for assessment of disability and neurological dysfunction. RESULTS: Eighteen patients had a cerebellar infarct (posterior inferior cerebellar artery territory in 9 patients, superior cerebellar artery in 6, anterior inferior cerebellar artery in 2, nonterritorial in 1). Two patients had lateral medullary infarcts and 2 isolated pontine infarcts. In 2 patients MRI was normal despite repeated investigations. Hearing loss and tinnitus were the only explicit symptoms for superior cerebellar artery infarcts, but it was otherwise impossible to classify each case to a vascular territory according to clinical characteristics. The age-specific incidence of isolated cerebellar infarction was 1.8/100,000/year. The presumed causes were arterial dissection in 8 patients, idiopathic in 7, cardioembolic in 5, oral contraceptive use in 3 and protein S deficiency in 1 patient. One patient died during the acute phase and another developed a locked-in syndrome. At follow-up, 1 patient had a transitory ischemic attack and 1 a silent cerebral infarction. Twenty-two patients had a favorable outcome according to the modified Rankin scale (grade 0-2) and the NIH scale. CONCLUSIONS: Cerebellar infarctions are frequent among young stroke patients in northern Sweden. Arterial dissection is the prevailing stroke mechanism in infratentorial infarcts. The prognosis is favorable regarding motor impairment but cognitive deficits may prevent return to work.

Adolescent↗
PubMedDate not supplied

The diagnostic value of pericardial cytology. An analysis of 95 cases.

Cytologic specimens of 105 pericardial fluids collected from 95 cases during a seven-year period were reviewed. Clinical reports and descriptions of the histologic antemortem and postmortem specimens were correlated with the cytologic diagnoses, and the interobserver variation was estimated. Of the collected material, 48.4% was from patients suspected of having nonmalignant disorders, 40.0% was from patients with previously diagnosed carcinomas and 11.6% was from cases in which the etiology was unknown at the time of pericardiocentesis. Cytologic examination of the pericardial fluids revealed tumor cells in a sample from one patient suspected of having a heart disorder and in a sample from another patient with an obscure disease. Of the pericardial fluids from the cancer patients, 66.7% contained malignant cells; the most frequent primary site in these cases was the lung. Correlated with the histologic diagnosis, the specificity of cytology was 100%. The results prove that, in experienced hands, pericardial cytology is a valuable diagnostic tool.

Carcinoma↗