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Biomedical subjects

A Brand

Publications and source records attributed to A Brand.

At least 145 records · Page 8Linked to original sources
PubMed1996

The kinetics of HLA class I elution and the relevance for the use of HLA-eluted platelet transfusions.

HLA-eluted platelet transfusions may be feasible for transfusion in HLA-alloimmunized refractory patients, but the reduction in HLA expression after elution is variable. Using different anti-HLA antibodies directed against the HLA class I complex, the heavy chain, beta 2-microglobulin (beta 2M) and the intracytoplasmatic part of the heavy chain, we investigated factors which influenced the HLA reduction by flow cytometry. Reduction of HLA expression by acid treatment resulted in an almost complete removal of HLA class I molecules from the site of the intracytoplasmatic part of the heavy chain. Re-expression of HLA heavy chain, beta 2M and some of the trimolecular complex (comprised by beta 2M, heavy chain and peptide) occurred within 4 h. This was presumably the result of adsorption from the supernatant (eluate or plasma). After immediate removal of the eluate and incubation in plasma-free supernatant no re-expression of HLA occurred after a 4 h interval.

Absorption↗
PubMed1996

HLA class I-eluted platelets as an alternative to HLA-matched platelets.

BACKGROUND: Alloimmunized refractory thrombocytopenic patients often require HLA-matched platelet transfusions. As the HLA system is very polymorphic, sufficient HLA-matched donors are not available for every patient. STUDY DESIGN AND METHODS: In vitro elution techniques with citric acid incubation of platelets at pH 3.0 showed that platelets lose expression of HLA, whereas platelet-specific glycoproteins are preserved. This technique was modified for clinical use. Random-donor platelet concentrates were incubated with citric acid, subsequently washed, and transfused to two patients. RESULTS: Platelet-specific glycoproteins were unaffected, and HLA expression decreased generally to below 25 percent of the initial expression. One alloimmunized patient who was without compatible donors because of a rare HLA type underwent repeated transfusions with acid-treated platelets. In contrast to the results with random-donor platelet transfusions, posttransfusion increments up to 47 x 10(9) per L were obtained with acid-treated platelets, and profuse gastrointestinal bleeding was stopped, while multiple skin hemorrhages were resolved. No side effects were observed. A second patient developed a severe transfusion reaction without platelet increment after one transfusion with acid-treated platelets expressing 30 percent of the original HLA antigens. Further transfusions were not given. CONCLUSION: Standardization of the acid elution technique and validation of the technique in patients is necessary. The results suggest, however, that HLA-eluted platelets prepared under specified conditions may gain a place in platelet transfusion therapy.

Adult↗
PubMed1996

[Memory disturbances in schizophrenia].

The recent literature on memory disorders in schizophrenic persons is reanalysed. The present interest in memory disorders as a core symptom of cognitive changes in schizophrenia derives from the fact that brain imaging methods have revealed a reduction of substance in the regions surrounding the lateral ventricles. Given this localisation, schizophrenics should suffer from pronounced memory deficits. The paper addresses (1) the role of memory disorders in an overall view of cognitive losses, (2) the pattern of memory losses (verbal vs non-verbal, short-term memory vs long-term memory, implicit vs explicit memory etc.) and (3) recent investigations based on simultaneous use of imaging procedures (fNMR, PET) and cortical activation during memory tasks. A survey of the literature renders it likely that frontal functions play an essential role in the type of memory deficits found among schizophrenics. Thus, a purely temporal localisation is unlikely. The reduced learning efficiency which accounts for most of the schizophrenics' cognitive problems points to a working memory disturbance. On the basis of these results, a model for the memory disorders of schizophrenics is developed. The model covers recent literature on working memory as well as neural network models of schizophrenic disorders. However, a differential psychopathological symptom and syndrome analysis remains a prerequisite for reducing the great variance of the schizophrenics' performance in memory tasks. The importance of cognitive rehabilitation for sociopsychiatric efforts aimed at re-integrating mentally ill persons should not be underestimated.

Humans↗
PubMed1996

Experimental reproduction of respiratory disease in calves with non-cell-culture-passaged bovine respiratory syncytial virus.

To reproduce experimentally clinical bovine respiratory syncytial virus (BRSV) infections in cattle, we isolated BRSV from a calf in the field that suffered from acute respiratory disease. Cell culture passage of the virus was avoided to prevent any modification of the biological properties of the virus. The isolated BRSV was passaged in specific-pathogen-free (SPF) calves. Lung lavage fluids of these calves, which contained at least 10(3) TCID50/ml BRSV and which were found to be free of other known respiratory pathogens, were collected and pooled for experimental infection. To reproduce a clinical BRSV infection, two groups of six SPF calves were inoculated intranasally with 2 ml of 10(3.9) TCID50/ml BRSV of the obtained virus stock. Another five calves, which were persistently infected with bovine virus diarrhoea virus (BVDV), were given the same inoculum. One group of six calves served as mock-infected controls. Clinical signs were closely monitored from 1 week before until 16 days after inoculation. Reproducible clinical signs consisting of significantly (p < 0.05) increased respiratory rates and elevated body temperatures were recorded but not in all BRSV-inoculated calves. Although clinical signs were induced by experimental infection with non-cell-culture-passaged BRSV, the respiratory signs were not as serious as in the most severe cases in the field.

Administration, Intranasal↗
PubMed1996

Primary and recurrent colorectal cancer masquerading as gynaecological malignancy.

To make clinicians more aware of the phenomenon of primary and recurrent colorectal and anal carcinoma masquerading as primary gynaecological malignancy, we reviewed the records of 8 women referred to our gynaecological oncology unit with primary colorectal cancer (1), recurrent colorectal cancer (6) and primary anal cancer (1). Seven of these patients presented with abnormal vaginal bleeding or discharge. All patients had Papanicolaou smears performed; 7 were abnormal and 1 unsuitable for cytological assessment. None of the 6 patients with recurrent carcinoma had been previously treated with more than standard anterior or abdominoperineal resection; no radiotherapy had been given, and only 1 patient had received chemotherapy. These patients were treated in our gynaecological oncology unit for their recurrence by surgery and/or chemotherapy and/or irradiation. All 6 had further recurrences in the pelvis despite this aggressive therapy. Follow-up of colorectal cancer in women should involve gynaecological history, pelvirectal examination and Pap smear at each visit. Correct diagnosis of the colorectal origin of a genital tract tumour is made on careful history, examination and biopsy. An abnormal Pap smear may be the first indication of recurrent colorectal cancer in the cervix and vagina, although most patients ultimately present with abnormal vaginal bleeding. The presence of a tumour invading both cervix and posterior vaginal wall is suggestive of spread from a colorectal tumour compared to the more common lateral spread of a cervical primary.

Adult↗
PubMed1996

Immobilization of primary astrocytes and neurons for online monitoring of biochemical processes by NMR.

Immobilization of primary astrocytes and cerebellar granule neurons in basement membrane gel threads and on porous microcarriers, respectively, is described. Five different porous microcarriers were examined for their capabilities to support maturation of neurons, as evaluated by determinations of protein content and glucose uptake. These systems proved suitable for perfusion in the NMR tube for long periods of time. The energetic status of the cells was monitored by 31P-NMR, and a very good temporal resolution (less than 30 min) was achieved with superfused astrocytes; thus, this provides a valuable method for real time NMR investigation of biochemical processes in primary astrocytes. Significantly longer acquisition times (approximately 8 h) were required in order to obtain a spectrum of neurons with a reasonably good signal to noise ratio, even so, the results presented here and obtained with this difficult system are very encouraging.

Animals↗
PubMed1996

Detection of Bence-Jones protein in serum by immunoblotting.

To detect Bence-Jones protein (BJP) in serum we precipitated intact immunoglobulins (Ig) using polyethylene glycol (PEG) and subjected the BJP in solution to electrophoresis in agarose gel, followed by transfer to a polyvinylidene difluoride membrane, and immunoenzymatic staining (successively using rabbit anti-human light/heavy chain of Ig, biotinylated swine anti-rabbit Ig, and alkaline phosphatase-conjugated streptavidin). Treatment with PEG effectively reduced background staining of polyclonal Ig in the immunoblots, although intact monoclonal Ig was not always completely removed. To compare the present method with immunoelectrophoresis (IEP), we selected samples from patients demonstrating BJP by IEP in both serum and urine (n = 40), serum only (n = 18), and urine only (n = 32); 21 of these patients had BJP alone and 69 had BJP in addition to intact monoclonal Ig. Efficiency of detection of BJP in serum was increased by the present method: serum BJP was detected in 70 patients by the present method versus 58 by IEP. The present method demonstrated single BJP bands in the samples from 16 patients (kappa, n = 7; lambda, n = 9) and multiple BJP bands (range: 2-9) in the samples from 54 patients (kappa, n = 31; lambda, n = 23). This method could be useful for detecting BJP in serum from patients suspected of having light chain gammopathy (without the need for urine testing) and may complement urine testing in patients excreting polyclonal free light chains of Ig.

Antibodies, Monoclonal↗
PubMed1996

Mathematical modeling to estimate efficacy of postmilking teat disinfection in split-udder trials of dairy cows.

A mathematical model was used to estimate the efficacy of postmilking teat disinfection from observations in split-udder trials with natural exposure. Data were studied from an outbreak of Staphylococcus aureus IMI during a split-udder trial in a commercial herd with low SCC. The efficacy of postmilking teat disinfection was similar when calculated based on incidence density rates or on transmission rates of IMI in dipped and control quarters. If, however, first and subsequent S. aureus IMI in a cow were not assumed to be independent and were therefore treated separately in the models, the efficacy of post-milking teat disinfection was calculated as being higher with the modeling procedure. The analysis using mathematical modeling, which includes the effect of the number of existing IMI on the number of new IMI, is presented and discussed. This analysis also allows estimation of the basic reproduction ratio. The impact of postmilking teat disinfection on transmission of pathogens is quantified, and proposals for additional preventive measures can be generated. We concluded that efficacy estimations from split-udder trials, assuming quarters to be independent observations, might underestimate the effect of postmilking teat disinfectants on udder pathogens.

Animals↗
PubMed1996

Epidemiological characteristics of bovine clinical mastitis caused by Staphylococcus aureus and Escherichia coli studied by DNA fingerprinting.

OBJECTIVE: To study the epidemiology of clinical mastitis caused by Escherichia coli and Staphylococcus aureus by differentiating isolates with DNA fingerprinting techniques, using polymerase chain reaction. DESIGN: Milk samples were collected from cases of clinical mastitis in dairy cows. Escherichia coli and S aureus isolates from these cases were compared within and between cows and herds. SAMPLE POPULATION: Seven dairy herds with an average bulk milk somatic cell count < 150,000/ml, and incidence of cows with clinical mastitis of > 25%/y. PROCEDURE: Chromosomal DNA was isolated from E coli and S aureus strains isolated from cases of clinical mastitis, and amplified by polymerase chain reaction, using enterobacterial repetitive intergenic consensus primers for E coli and a random amplified polymorphic DNA primer for S aureus. Escherichia coli and S aureus strains were identified and differentiated, using their DNA polymorphism pattern. RESULTS: Multiple E coli genotypes were found in each of the herds. Persistent infections with E coli were sporadic. Only a limited number of different S aureus genotypes was found in each of the herds studied. Recurrent cases of S aureus mastitis were found in 25% of quarters with clinical S aureus mastitis. Comparing S aureus isolates from different herds indicated that 1 S aureus genotype was most prevalent. CONCLUSIONS: Because different quarters were infected with different genotypes, it was concluded that E coli is an environmental pathogen, and does not generally spread from quarter to quarter. The hypothesis that S aureus mastitis is a contagious disease, spreading from infected to uninfected quarters, could not be rejected.

Animals↗
PubMed1996

Quantitative investigation of population persistence and recurrent outbreaks of bovine respiratory syncytial virus on dairy farms.

OBJECTIVE: To determine if transmission of virus among seropositive cattle is a plausible mechanism for the permanent presence of bovine respiratory syncytial virus (BRSV) in dairy herds, and how likely, with the scenario for persistence, there will be only 1 clinical outbreak of BRSV per year. DESIGN: Build a stochastic model, parameter estimation from serologic data on BRSV, and interpret the estimated parameter values from the model analysis. SAMPLE POPULATION: Monthly data on the prevalence of antibodies directed against BRSV in sera from all cattle in 6 dairy herds. PROCEDURE: Parameter estimation applying general linear models, model analysis using calculation of the reproduction ratio for simplified models, and Monte-Carlo simulation for the whole model. RESULTS: Persistence of BRSV by transmission among seropositive cattle given estimated parameter values would be accompanied by frequent extinctions (once every 10 to 50 years) and long infectious periods in seropositive cattle (100 days). Moreover, in the model, a single clinical outbreak among seronegative cattle only occurred with external forcing. CONCLUSIONS: From these data, transmission among seropositive cattle is not a plausible mechanism for persistence of BRSV in dairy herds.

Animals↗
PubMed1995

Persistence of bovine herpesvirus-1-specific antibodies in cattle after intranasal vaccination with a live virus vaccine.

To study the development and persistence of circulating antibodies directed against bovine herpesvirus-1 (BHV-1) induced by vaccination, approximately 80 per cent of the seronegative cows in four partly seronegative dairy herds were vaccinated once with a temperature-sensitive live virus vaccine. Most (83 per cent) of the vaccinated animals developed antibodies to BHV-1 within two months after the vaccination. In the same period, 21 per cent of the unvaccinated control cattle also seroconverted, suggesting that the vaccine virus had been transmitted to them. Thirty months after they had been vaccinated 91 per cent of the vaccinated animals which responded still had detectable antibodies. The results suggest that vaccine-induced antibodies may persist for years and thus may interfere with control programmes for BHV-1 which are based on serological monitoring.

Administration, Intranasal↗
PubMed1995

Occurrence of allogeneic HLA and non-HLA antibodies after transfusion of prestorage filtered platelets and red blood cells: a prospective study.

The incidence and consequences of HLA and non-HLA immunization were evaluated in 229 patients with aplastic thrombocytopenia. All patients were transfused with prestorage filtered red blood cells and platelets. On admission, 29 patients presented with HLA antibodies due to prior immunization by pregnancy and/or blood transfusions. Of the 200 patients showing no detectable HLA antibodies on admission, 164 could be evaluated. HLA antibodies developed in 2.7% (3 of 112) of the patients with a negative risk history of prior immunization. The occurrence of HLA antibodies in patients with a history of previous pregnancies or prior non-leukocyte-depleted blood transfusions (risk history positive) was 31% (16 of 52). Of the total of 48 patients who were or became alloimmunized, 92% (44 of 48) had a positive risk history. Ten patients with broad multispecific HLA antibodies with a panel reactivity (PRA) of greater than 70% required transfusions with HLA-matched platelets. Patients with HLA antibodies with lower PRA could be supported by random donor platelets. Two patients developed platelet-specific antibodies, causing transfusion refractoriness that necessitated selecting platelets by the absence of a platelet-specific antigen. Using prestorage leukocyte depletion of red cells and platelets with less than 5 x 10(6) residual leukocytes, 95% of the patients, including patients with a previous risk history or with HLA antibodies with low PRA, can be supported with random donor transfusions for the entire duration of their thrombocytopenic periods.

Abdominal Pain↗
PubMed1995

[Production management on dairy farms: the road to the future].

In this paper the developments in the field of bovine herd health and production management are illustrated. The current use of herd health and production management methods in veterinary practices are illustrated, and a uniform concept for execution of herd health and production management programs is given. The expected future developments and the critical points in these developments are discussed. The changing role of the veterinarian in bovine practice with the application of herd health is outlined.

Animals↗
PubMed1995

Leukocyte depletion of random single-donor platelet transfusions does not prevent secondary human leukocyte antigen-alloimmunization and refractoriness: a randomized prospective study.

We studied the value of leukocyte depletion of platelet transfusions for the prevention of secondary human leukocyte antigen (HLA)-alloimmunization in patients with a high-risk of prior immunization induced by pregnancies. Seventy-five female patients with hematologic malignancies (mostly acute leukemia) and a history of pregnancy were randomized to receive either standard random single-donor platelet transfusions (mean leukocytes, 430 x 10(6) per transfusion) or leukocyte-depleted random single-donor platelet transfusions. Leukocyte depletion to less than 5 x 10(6) leukocytes per platelet transfusion (mean leukocytes, 2 x 10(6) per transfusion) was achieved by filtration. Of the 62 evaluable patients, refractoriness to random donor platelets occurred in 41% (14 of 34) of the patients in the standard group and in 29% (8 of 28) of the patients in the filtered group (P = .52); anti-HLA antibodies developed in 43% (9 of 21) of individuals in the standard group and 44% (11 of 25) of cases in the filtered group. The time toward refractoriness and development of anti-HLA antibodies was similar for both groups. We conclude that leukocyte depletion of random single-donor platelet products to less than 5 x 10(6) per transfusion does not reduce the incidence of refractoriness to random donor platelet transfusion because of boostering of anti-HLA antibodies.

Adult↗
PubMed1995

Anti-beta-tubulin antibodies have no diagnostic value in patients with chronic inflammatory demyelinating polyneuropathy.

High-titre anti-beta-tubulin antibodies were recently reported to occur in over 50% of sera from patients with chronic inflammatory demyelinating polyneuropathy (CIDP). It was concluded that these antibodies may help to distinguish CIDP from other neuropathies and that they are diagnostically useful. To verify these findings, we studied sera of 43 CIDP patients, only 3 of whom had anti-beta-tubulin antibodies. The differences between the results obtained cannot fully be explained by differences between patients or antigens but may be explained by the use of different techniques (Western blot versus ELISA). We used Western blot, which is less sensitive but far more specific, to detect these antibodies. The findings of our study did not confirm the high frequency of selective high-titre anti-beta-tubulin antibodies in CIDP patients. Therefore we conclude that binding to beta-tubulin by Western blot cannot serve as a marker of CIDP.

Adult↗
PubMed1995

Changes in organic solutes, volume, energy state, and metabolism associated with osmotic stress in a glial cell line: a multinuclear NMR study.

Diffusion-weighted in vivo 1H-NMR spectroscopy of F98 glioma cells embedded in basement membrane gel threads showed that the initial cell swelling to about 180% of the original volume induced under hypotonic stress was followed by a regulatory volume decrease to nearly 100% of the control volume in Dulbecco's modified Eagle's medium (DMEM) but only to 130% in Krebs-Henseleit buffer (KHB, containing only glucose as a substrate) after 7 h. The initial cell shrinkage to approx. 70% induced by the hypertonic stress was compensated by a regulatory volume increase which after 7 h reached almost 100% of the control value in KHB and 75% in DMEM. 1H-, 13C- and 31P-NMR spectroscopy of perchloric acid extracts showed that these volume regulatory processes were accompanied by pronounced changes in the content of organic osmolytes. Adaptation of intra- to extracellular osmolarity was preferentially mediated by a decrease in the cytosolic taurine level under hypotonic stress and by an intracellular accumulation of amino acids under hypertonic stress. If these solutes were not available in sufficient quantities (as in KHB), the osmolarity of the cytosol was increasingly modified by biosynthesis of products and intermediates of essential metabolic pathways, such as alanine, glutamate and glycerophosphocholine in addition to ethanolamine. The cellular nucleoside triphosphate level measured by in vivo 31P-NMR spectroscopy indicated that the energy state of the cells was more easily sustained under hypotonic than hypertonic conditions.

Animals↗