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Biomedical subjects

A Brand

Publications and source records attributed to A Brand.

At least 271 records · Page 15Linked to original sources
PubMed1989

Effect of freezing on bacteriologic culturing of mastitis milk samples.

The objective was to determine the effect of freezing and length of freezing in a commercial freezer on the qualitative results of bacteriologic culturing of milk collected from glands of cows with clinical or subclinical intramammary infections. A total of 182 milk samples from cows with clinical mastitis and 55 milk samples of cows with subclinical mastitis were taken from four problem herds. Samples were split into four equal sub-samples. Three of these were frozen immediately at -20 degrees C and 1 was submitted fresh for bacteriologic analysis. At 4, 8, and 16 wk after collection, samples were thawed and submitted for bacteriologic culturing. Freezing and increased length of storage resulted in 1) a decrease in the number of samples that had cultures of Escherichia coli or Actinomyces pyogenes; and 2) an increase in the number of samples that had cultures of coagulase-negative staphylococci. Freezing had no effect on streptococci and Staphylococcus aureus.

Actinomyces↗
PubMed1989

Lymphokine-activated killer cells selectively kill tumor cells in bone marrow without compromising bone marrow stem cell function in vitro.

Although it has been demonstrated that lymphokine-activated killer (LAK) cells kill tumor cells in a selective way without being toxic to a variety of normal cells, contradictory results exist about the possible toxicity of natural killer (NK) and LAK cells for hematopoietic progenitor cells. Therefore, the cytolytic activity and growth inhibitory effects of LAK cells on normal bone marrow progenitor cells and the ability of LAK cells to eliminate neoplastic hematopoietic cells from populations of bone marrow cells in vitro was studied. The results of these experiments show the following: (1) LAK cells have little cytolytic activity against normal bone marrow cells; (2) normal bone marrow cells fail to cold target compete for the killing of the hematopoietic tumor cell lines K562 and HL60 or freshly frozen acute myelocytic leukemia (AML) blast cells by LAK cells; (3) LAK cells inhibit the growth of K562 and HL60 to more than 90% in clonogenic assays; (4) LAK cells have no inhibitory effect on hematopoietic progenitor growth in CFU-GM (colony-forming unit-granulocytes, macrophages), CFU-E (colony-forming unit-erythrocytes), BFU-E (burst-forming units-erythrocytes), or CFU-GEMM (colony-forming unit-granulocytes, erythrocytes, macrophages, megakaryocytes) assays. These results indicate that LAK cells have low toxicity for normal bone marrow and that LAK activity against tumor cells is not adversely affected by the presence of normal bone marrow cells. The differences in cytolysis and growth inhibition of neoplastic hematopoietic cells and hematopoietic progenitor cells by LAK cells in vitro could create a therapeutic index that might allow the use of LAK cells for cleansing of the autologous bone marrow graft and for adjuvant therapy in combination with autologous bone marrow transplantation without compromising the reconstitution of the bone marrow in the host.

Bone Marrow↗
PubMed1988

[Practical application of recombinant bovine somatotropin: sequelae for man, animal and animal husbandry].

Recombinant Bovine Somtatotropin (r-BST) may be produced commercially in the forseeable future. On the basis of a study of the literature, it may be assumed in all likelihood that administration of r-BST to dairy cows will not have a negative effect on public health. However additional research on potential biological activity of recombinant-BST or its fragments and of somatomedins after oral administration, is advisable. Negative effects on the health, fertility and life-span of animals were not observed so far under experimental conditions but any reference to field situations is absent in the literature. Treatment with r-BST should not be initiated prior to within eighty days after parturition. Administration of r-BST also requires proper management in terms of ration formulation and feeding to ensure maintenance of health and production of dairy cattle. The use of r-BST will result in a less accurate estimation of the breeding potential of selected cows, resulting in a reduction of the genetic improvement of milk production. Increased economic benefits should be obtained on farms having high stocking rates (2.35 dairy cows/ha) compared with those having low stocking rates (1.90), varying with the price of r-BST. It is anticipated that the use of r-BST will have little effect on the reduction of the number of dairy cattle and dairy farms up to 1995.

Animal Husbandry↗
PubMed1988

[Somatotropin: endocrinological aspects].

Bovine somatotropin (BST) is a polypeptide hormone produced by the pituitary gland. Its release is regulated by hypothalamic hormones such as the Growth Hormone Releasing Factor (GRF) and the Somatotropin Release Inhibiting Factor (SRIF). Unlike somatotropin, GRF en SRIF are not species-specific. Somatotropin is released into the blood, and then bound to receptors which are present in various tissues but not in those of the mammary gland. Binding of somatotropin to receptors of hepatocytes results in the synthesis of somatomedins which are mediators of somatotropin. Receptors for somatomedins were recently found to be present in mammary gland tissue. The release of somatotropin is pulsatile and is influenced by steroids, genetic factors, nutrition and pregnancy. The effect of BST is dependent on its average concentration in the plasma and not on a particular pattern in this concentration. The effect of administration of BST prior to peak lactation is variable, but subsequently continuous to be positive. It therefore is advisable to start treatment after day 90. In the future, administration of recombinant-BST will be performed through slow-release preparations.

Animals↗
PubMed1988

[Somatotropin: structure, (bio)synthesis and species specificity].

The literature on biosynthesis and species specificity of bovine somatotropin (BST) is reviewed. Somatotropin is a hypophyseal hormone consisting of 190 amino acids, having, among other things, a stimulating effect on milk synthesis. Recombinant DNA-techniques have been used since 1982 to produce BST and this has paved the way for large-scale use of r-BST. It is assumed that the somatotropin molecule has several active sites responsible for a multitude of biological effects following interaction with specific receptors. Somatotropin of different animals have a varying amino acid composition. Sixty-five per cent of human and bovine somatotropins are homologues in amino acid sequence. BST is found to be virtually inactive when used therapeutically in human individuals.

Amino Acid Sequence↗
PubMed1988

Association of HLA-DR2 antigen with serum IgG antibodies against Borrelia burgdorferi in Bannwarth's syndrome.

The frequency of the HLA-DR2 antigen in 33 patients with clinical symptoms and signs of Bannwarth's syndrome was 33%, which was not significantly different from the 29% occurrence in 505 control subjects. However, all 11 HLA-DR2-positive patients had elevated serum levels of IgG antibodies against Borrelia burgdorferi, and these were present in 45% of 22 HLA-DR2-negative patients (P = 0.004). In the 21 patients with anti-B. burgdorferi antibodies the frequency of HLA-DR2 was 52%, which is significantly higher than the frequency in the control group (P = 0.04). The diagnosis of Bannwarth's syndrome was serologically confirmed by a positive indirect immunofluorescence assay (IFA). A negative test result does not exclude the diagnosis, as has recently been demonstrated with more sensitive techniques. The association between HLA-DR2 and a positive IFA suggests that the IFA selects a subgroup of patients with Bannwarth's syndrome and a different immune response. We could not demonstrate differences in the clinical spectrum and outcome between the two groups.

Antibodies, Bacterial↗
PubMed1988

Myocardial damage after a scorpion sting: long-term echocardiographic follow-up.

A seven-year-old girl, stung by a scorpion, was hospitalized in a confused state with signs of myocarditis and pulmonary edema. In spite of clinical improvement within 24 h, 14 serial echocardiograms and electrocardiograms performed during a four-month period showed severe changes. There have been no previously published reports of echocardiographic studies showing myocardial changes after a scorpion sting.

Animals↗
PubMed1988

The introduction of expert systems in animal husbandry.

The intensive nature of modern animal husbandry has changed the environmental conditions, so that protection against diseases, especially those caused by secondary pathogenic organisms, becomes an increasing concern. Production inefficiencies become more and more important. Because of their complex nature, many associated problems cannot be solved by farmers alone. With the introduction of information technology in the form of expert systems, new possibilities emerge for maximal productivity and animal health. Expert systems are a new type of computer programmes which are able to handle problems in limited domains at an expert level, using expert knowledge and reasoning processes, within strictly defined problem limits. Expert systems as they presently exist have the following components: a knowledge base (rule- and data-base), inference engine (deductive mechanism), user-interface (explanatory facilities, etc.). The application of knowledge engineering in animal husbandry may result in improvements in the general health and productivity of the herd and the financial returns of the farm, derived from the improved managerial control. At the same time the use of knowledge engineering may lead to greater understanding of the various epidemiological factors that influence farm results, either positively or negatively.

Animal Husbandry↗
PubMed1988

The interaction between the Lewis blood group system and HLA-matching in renal transplantation.

A retrospective study was initiated to investigate the influence of recipients' Lewis subtype and HLA-matching on cadaveric kidney graft outcome. A total of 1111 patients receiving a first cadaveric kidney graft were analyzed. No difference in one-year graft survival was found between Lewis-negative (73%, n = 133) and Lewis-positive (73%, n = 978) recipients. Further subdivision of the study group into HLA-A,-B well-matched (0 or 1 mismatches [MM]) and poorly matched (2, 3, or 4 MM) revealed a strong deleterious effect of HLA-A,-B mismatching in the Lewis-negative group only. One year graft survival in Lewis-negative HLA-A,-B poorly matched (2, 3, or 4 A,B MM) patients was 60% (n = 67) versus 86% (n = 66) in the Lewis-negative HLA-A,-B well-matched (0 or 1 A,B MM) group (P = 0.004). For the Lewis-positive group the one-year graft survival rates were 72% (2, 3, or 4 A,B MM; n = 498) and 74% (0 or 1 A,B MM; n = 480), respectively (P = n.s.). The additional beneficial effect of HLA-DR matching again turned out to be strongest in the Lewis-negative group. In Lewis-negative, HLA-DR (0 MM) and -A,-B well-matched recipients (n = 36) graft survival was 94% versus only 64% in the Lewis-negative, DR matched, A,-B mismatched (2, 3, or 4 A,B MM) group (n = 25; P = 0.09). In the Lewis-positive, HLA-DR 0 mismatched group the one-year survival rates were 78% (0 or 1 A,B MM; n = 240) and 73% (2, 3, or 4 A,B MM; n = 253), respectively (P = 0.05). Our data suggest that donor recipient selection should not be based on Lewis matching per se. However, since Lewis-negative patients are at high risk of graft failure when receiving HLA mismatched kidneys, they should preferentially receive optimally HLA matched grafts.

ABO Blood-Group System↗
PubMed1988

Beneficial effect of intravenous gammaglobulin in a patient with complement-mediated autoimmune thrombocytopenia due to IgM-anti-platelet antibodies.

Intravenous gammaglobulin (IV-IgG) was administered to a patient with chronic idiopathic thrombocytopenic purpura due to an unusual IgM platelet autoantibody causing in vitro complement-dependent thrombocytoxicity and in vivo intravascular platelet destruction. After IV-IgG infusion the peripheral platelet count temporarily increased to normal values, the mean platelet survival time increased and the platelet sequestration pattern changed from intravascular to predominantly hepatic destruction. In vivo and in vitro observations in this patient illustrate a transient beneficial effect of gammaglobulin infusion due to interference with the complement-fixing autoantibodies against platelets.

Aged↗
PubMed1988

Evolution of acquired severe aplastic anaemia to myelodysplasia and subsequent leukaemia in adults.

Myelodysplasia (MDS) and leukaemia following acquired aplastic anaemia has been reported as a rare event occurring in about 5% of patients. Improved results in survival of patients with severe aplastic anaemia (SAA) and subsequent prolonged follow-up created the possibility of evaluating the occurrence of MDS and leukaemia in 38 adult patients with acquired SAA surviving two or more years without bone marrow transplantation. Five patients, age 22, 35, 47, 56, 72 years, two females, three males, all with idiopathic SAA and normal cytogenetic analysis developed a refractory anaemia (RA) 7, 30, 48, 56, 142 months after diagnosis of SAA. In 3/5 RA evolved into an acute myeloid leukaemia (AML) either via a chronic myelomonocytic leukaemia (CMML) (2/3) or via RA with excess of blasts (RAEB) (1/3). Three patients revealed a monosomy 7 during MDS and/or leukaemic phase. One patient died during RA phase without cytogenetic abnormalities. A pattern of evolution could be identified in these patients revealing well-documented SAA - improvement of bone marrow haematopoiesis - dyshaematopoietic features of one or more cell lines with predominance of dyserythropoiesis - RA - RAEB or CMML - AML. These five patients represent more than 10% of all patients surviving at least 2 years. This implies that the risk of developing MDS and leukaemia in SAA patients surviving with autologous marrow, might increase with longer follow-up.

Adult↗
PubMed1988

Alloimmunization after leukocyte-depleted multiple random donor platelet transfusions.

In a prospective study we investigated the development and the course of alloimmunization after leukocyte-depleted red cell and multiple random donor platelet transfusions in 335 patients. Of these 335 patients, who had a negative antibody screening on admission and a negative transfusion history, 69 (21%) developed either transient (n = 18) or permanent (n = 51) lymphocytotoxic antibodies, but only 31 patients (9%; 95% confidence limits 6-12%) developed multispecific alloantibodies necessitating HLA-matched platelet transfusions. There was no difference with regard to the development of antibodies and platelet refractoriness between leukemia patients receiving cytostatic treatment and patients with aplastic anemia receiving prednisone and antithymocyte globulin. Females with previous pregnancies developed platelet refractoriness with an increased incidence (Chi 2 13.38; p less than 0.001) compared to females without previous pregnancies, males, and children.

Blood Platelets↗
PubMed1988

Minor histocompatibility antigen H-Y is expressed on human hematopoietic progenitor cells.

Polymorphic minor transplantation antigens probably play an important role in immune mediated graft rejections of bone marrow transplants. Mapping of these antigens on hematopoietic progenitor cells (HPC) is important since these antigenic determinants may serve as target structures in the rejection process, and it ultimately opens the possibility to match for these antigens. Using a cell-mediated cytotoxicity assay with H-Y-specific cytotoxic T lymphocytes as effector cells, a dose-dependent growth inhibition up to 100% of myeloid (CFU-GM), erythroid (BFU-E) and multipotential (CFU-GEMM) HPC of male donors was obtained, indicating expression of the H-Y antigen on these progenitor cells. In contrast, inhibition of relatively mature erythroid and myeloid progenitor cells was only 40-50%, indicating that the recognition of the H-Y antigen diminished during maturation of erythroid and myeloid HPC. Our results show that the H-Y antigen can be recognized on HPC as a target for cytotoxic T cell responses. This may be important in graft rejection of male donor bone marrow grafts by female recipients.

Bone Marrow↗
PubMed1988

Anti-neuroblastoma cell line antibodies in inflammatory demyelinating polyneuropathy: inhibition in vitro and in vivo by IV immunoglobulin.

We tested serum from 48 patients with Guillain-Barré syndrome and 42 with chronic inflammatory demyelinating polyneuropathy (CIDP) against a selected neuroblastoma cell line (NBL 108cc15). Forty-two percent of the patients showed a positive immunofluorescence test against the NBL 108cc15. These antibodies were mainly of the IgM-class; they disappeared in all seven CIDP patients retested after improvement following intravenous IgG treatment (IV-IgG) and were present in only 5% of serum from patients with other disorders. Absorption studies showed a partial homology between the NBL 108cc15 and human sciatic nerve. In vitro studies showed that IgG from pooled normal donors (IV-IgG) inhibits the reaction between serum from a CIDP patient and the NBL cell line. This inhibition may be due to neutralization of autoantibodies against nervous tissue by anti-idiotypic antibodies in IV-IgG.

Antibodies, Neoplasm↗
PubMed1988

Prevention of CMV infection by screening for CMV antibodies in renal allograft recipients and their blood and kidney donors.

The influence of the cytomegalovirus (CMV) serostatus of blood and kidney donors on patient and graft survival was studied prospectively in 73 cadaveric renal graft recipients. Six out of 12 (50%) CMV seronegative recipients receiving a kidney from a CMV seropositive donor developed CMV disease, in contrast to none of 7 CMV seronegative donor/recipient combinations. Transmission of CMV with blood products to seronegative recipients was not observed in this study. A poor graft survival of 41% 3 years after transplantation was found in CMV seronegative recipients with CMV seropositive allograft donors, compared with an actuarial 3 year graft survival of 72% in the 7 CMV seronegative donor/recipient combinations. Six patients with graft failure had a CMV infection. This study, in accordance with other studies, suggests that selection of CMV seronegative renal allograft donors for CMV seronegative recipients will improve graft survival.

Adolescent↗
PubMed1988

Growth of Escherichia coli in whole and skim milk from endotoxin-induced mastitic quarters: in vitro effects of deferoxamine, zinc, and iron supplementation.

A marked growth inhibition of Escherichia coli 0101 K99 F41 was observed in whole and skim milk collected from inflamed quarters 18 and 36 h after intramammary administration of .1 mg E. coli lipopolysaccharide. Individual cow variation in the ability of milk from endotoxin-infused quarters to inhibit growth of E. coli was found. Growth inhibition of E. coli was observed in milk from endotoxin-infused quarters and was most pronounced in skim milk sampled at postinfusion h 18, and incubated at 38 degrees C. The mechanism by which bacterial growth was depressed was probably of noncellular origin. Addition of Fe (45.5 micrograms/ml) and Zn (2.7 micrograms/ml) to whole and skim milk sampled from inflamed quarters at 18 h after endotoxin infusion resulted in a growth-promoting effect. Addition of deferoxamine (6 mg/ml) depressed bacterial growth. Effects of Fe, Zn, and deferoxamine on bacterial growth did not differ in whole and skim milk. No clear relationship was observed between reduction in Zn concentrations in skim milk from inflamed quarters at 18 h after endotoxin infusion and growth inhibition of E. coli in the same samples.

Animals↗
PubMed1988

Effect of dexamethasone on experimental Escherichia coli mastitis in the cow.

The effect of intramuscular administration of dexamethasone on milk production and on several clinical and hematologic indicators in cows with experimental Escherichia coli mastitis was studied. Two groups of three cows each were intramammarily inoculated with 20 x 10(5) cfu E. coli 0101 K99 F41 in rear quarters. Immediately after inoculation one groups received 30 mg dexamethasone intramuscularly, whereas the other group was injected similarly with pyrogen-free saline. Fourteen days later milk production losses were markedly less in the dexamethasone-treated group. Dexamethasone treatment reduced local clinical signs of inflammation, significantly increased rectal temperatures, and diminished inhibition of rumen amplitude during the acute phase of infection. Moreover, cows treated with dexamethasone showed diminished neutropenia, more pronounced hypozincemia, and delayed onset in the decrease in plasma iron concentrations. Possible mechanisms by which these changes are accomplished are discussed.

Animals↗