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Biomedical subjects

P Jacobs

Publications and source records attributed to P Jacobs.

At least 289 records · Page 16Linked to original sources
PubMed1990

The role of the professional nurse in a bone marrow transplantation programme.

Two different methods of transplantation are available. The allogeneic procedure is the transfer of bone marrow between compatible siblings, whereas in autografting the patient's own haematopoietic stem cells are collected, stored, and subsequently reinfused. Both forms have become established in the treatment of the leukaemias, aplastic anaemia, the malignant lymphomas, myeloma and certain immunologic diseases. Similarly, these techniques are being used in solid tumour oncology to reconstitute bone marrow function after high doses of chemotherapy, which would otherwise result in irreversible myelotoxicity. The success of such programmes depends upon a well developed multidisciplinary approach, prominently involving experienced and dedicated nursing staff. The latter individuals will establish contact with the patient typically during the first admission for chemotherapy and this will be consolidated during subsequent outpatient visits. Then follows the highly specialised care of central venous lines and management of radiation or chemotherapy-related side effects, often with intensive care needed for safe reversal of sepsis that may, however, be associated with renal or cardiorespiratory dysfunction. Most importantly, and again centrally involving the professional nurse, is responsibility for all aspects of maintaining and operating the protected environment, together with laminar air-flow rooms. Additional interaction is also necessary with dieticians, social workers, liaison psychiatrists, occupational therapists and frequently the infectious disease, cardiovascular, respiratory and renal services. Furthermore, achievement of optimal results presupposes the availability of a dedicated cell support section, as well as the competence to cryopreserve haematopoietic stem cells and monitor the safety of this step with in vitro bone marrow culture--another role for the specialised or academic nurse.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Transplantation↗
PubMed1990

Chemotherapy of adult acute nonlymphoblastic leukaemia.

Seventy-two consecutive and previously untreated adults with acute non-lymphoblastic leukaemia (ANLL), having a median age of 36 years (range 12 to 71), were prospectively randomised to receive conventional doses of cytosine arabinoside and doxorubicin combined with either etoposide (CTR III) or 6-thioguanine (DAT). Morbidity was comparable between the two regimens and complete remission (CR) rates of 52% and 62% respectively (p greater than 0.50) were not influenced by age above or below 50 years, initial white cell count, French-American-British classification, or race. However, growth pattern in the GM: CFUc assay was found to identify a subgroup of patients who had a significantly higher CR rate. Similarly, the secretion of tissue plasminogen activator by leukaemic blasts in vitro uniformly predicted for primary drug resistance, whereas a CR rate of 68% was associated with production of the urokinase type or a mixture of both enzymes. Remission duration and survival did not differ between these two forms of chemotherapy, nor were they influenced by immunotherapy with C. parvum or the duration of maintenance therapy, whereas age below 50 and the species of plasminogen activator secreted were significant prognostic factors. It is concluded that etoposide can be substituted for 6-thioguanine in these cytosine arabinoside and doxorubicin-containing regimens and that for both combinations the most sensitive prognostic factor for CR and survival is the species of plasminogen activator secreted in vitro by the leukaemic blasts.

Adolescent↗
PubMed1990

Bioavailability and the mechanisms of intestinal absorption of iron from ferrous ascorbate and ferric polymaltose in experimental animals.

The comparative bioavailability from matching quantities of iron in the form of ferrous ascorbate or ferric polymaltose was defined in rats. Studies were carried out in the intact animals under basal conditions and also when requirements for this metal were either increased or decreased by manipulating stores or erythropoietic activity. No significant difference was found in the total quantity of iron absorbed from either salt or complex under any of these circumstances, suggesting that the mucosal mechanism regulating the overall process was common to both. However, the rate of transfer from the lumen into portal blood was distinctive, reaching a maximum with salt at 30 min compared to 24 h for the complex. To explore the possibility that iron from the two sources was initially handled by different subcellular pathways, the radiolabeled compounds were instilled into loops of bowel that had been isolated between ligatures in vivo. Enterocytes were harvested and fractionated, and incorporation into ferritin and transferrin was determined using RIA. From salt, iron appeared rapidly in duodenal but not ileal ferritin, whereas mucosal transferrin increased under conditions of stimulated absorption, suggesting that this protein may act as a shuttle for the metal. In contrast, iron from polymaltose showed a cumulative incorporation into duodenal ferritin over time that correlated with iron absorption, defined by the appearance of radiolabel in the serum and in the carcass; a similar pattern was demonstrable in ileal mucosal cells. Conversely, binding of iron to transferrin was minimal. No iron polymaltose was found within the mucosal cells. It is suggested that the low rate of iron transfer from this ferric complex may reflect its extracellular breakdown in the lumen of the gastrointestinal tract.

Anemia, Hemolytic↗
PubMed1989

Immunophenotyping in the diagnosis and classification of acute leukaemia.

Ninety-four consecutive patients with acute leukaemia were analysed using cytochemical stains and, in selected individuals, a panel of monoclonal antibodies combined with measurement of the enzyme terminal deoxynucleotidyl transferase. These results were correlated with the French-American-British morphological classification. Acute non-lymphoblastic leukaemia was diagnosed in 55 individuals on the basis of morphology and cytochemical criteria; 6 of this group were further studied with antibodies directed against specific myelomonocytic antigens, but no further clinically useful information was obtained. Blasts from 36 patients did not stain with either Sudan black or myeloperoxidase. These individuals were considered to have acute lymphoblastic leukaemia (ALL) and were further assessed with monoclonal antibodies directed against epitopes expressed on cells of lymphoid lineage; 10 were classified as arising from T precursors; 23 were of B lineage, of which 13 marked as common, 6 as null, 1 as pre-B, 2 as B-ALL and 1 to have a pattern characteristic of lymphoblastic lymphoma. Two cases could not be classified and 1 was found to have megakaryoblastic features. In a further 3 patients who had undergone lymphoblastic transformation as a terminal event in the course of chronic granulocytic leukaemia, 2 were immunophenotypically common and 1 was marked as a null cell. This study confirms the value of monoclonal antibodies for accurately assigning lineage to the acute leukaemias and particularly in those situations where conventional morphological criteria and cytochemical markers are inconclusive.

Adult↗
PubMed1989

Auto-erythrocyte sensitisation--the Gardner-Diamond syndrome. A case report.

A 34-year-old woman with a 3-year history of easy bruising of unexplained aetiology in anatomical sites consistent with self-infliction is described. Despite major surgery, the patient had never experienced inappropriate bleeding. Owing to psychological instability, the possibility of auto-erythrocyte sensitisation was considered; this was confirmed by subcutaneous injection of autologous red cells and haemolysate, which caused local tenderness and induration. This manifestation of Gardner-Diamond syndrome is unusual and is reported to draw attention to its existence and perhaps thereby avoid unnecessary and costly investigations.

Adult↗
PubMed1989

Recombinant alpha-interferon as salvage therapy in multiple myeloma. A pilot study.

Ten patients with end-stage multiple myeloma refractory to conventional chemotherapy and hemibody irradiation received recombinant alpha-interferon as salvage therapy. The median duration of treatment was 8 weeks. One patient had an objective response and survived 8 months, whereas in the remaining 9 patients the disease progressed and median survival was 11.5 weeks. Side-effects were substantial and included confusion with extreme weakness, resulting in 5 patients refusing further therapy. The low response rate and the morbidity in this pilot study resulted in its discontinuation and the conclusion that recombinant alpha-interferon as single-agent therapy used for salvage in patients with refractory myeloma is of no value.

Aged↗
PubMed1989

The treatment of tumors by the induction of anemia and irradiation in hyperbaric oxygen.

Because increased effects have been achieved when murine tumors are irradiated after a period of hypoxia and because of anecdotal clinical experiences of an improved result after irradiation of previously anemic patients in hyperbaric oxygen, the relationship between irradiation and increased survival was investigated in seventy-two patients with advanced head and neck or cervical cancer. Anemia was achieved by means of a two-stage isovolemic venesection maintained for seventy-two hours, hemoglobin was returned to a normal level, and treatment in hyperbaric oxygen was started. Marked tumor shrinkage after the induction of anemia and before radiotherapy was seen and was probably disease, site, and hemoglobin level related. As a result, a possible new approach to cancer therapy is suggested. After completion of therapy, the 1-year disease-free survival for patients with head and neck and cervical cancer was not improved, but the 21-month survival for cervical cancer was improved. Further studies are strongly urged.

Adult↗
PubMed1989

Porcine D-amino acid oxidase: production of the biologically active enzyme in Escherichia coli.

DNA molecules coding either for mature porcine D-amino acid oxidase or for truncated forms of the enzyme have been obtained by stepwise addition of synthetic oligonucleotides to a partial cDNA. Under the control of the lambda PL thermoregulatable promoter, these DNAs were respectively expressed in Escherichia coli as 36, 28 and 25 kilodalton polypeptides, specifically recognised by antibodies raised against the natural enzyme. None of the truncated proteins were biologically active whereas the mature recombinant species was able to hydrolyze D-alanine in vitro as efficiently as the natural product.

Animals↗
PubMed1989

Regional thromboplastin standardisation using a human brain extract.

The preparation, regional distribution and standardisation of an acetone-dried extract of human brain thromboplastin was prospectively evaluated. The programme was shown to be easy to implement within the constraints of the World Health Organisation recommendations and offers a practical alternative to a national standard in countries where the cost of distribution and lack of expertise in preparing such material are limiting factors.

Animals↗
PubMed1989

Blood doping.

Explore the source record for details and available documents.

Blood Transfusion, Autologous↗
PubMed1989

A model to determine the feasibility of a pediatric practice.

A major concern of urban and rural citizens of the United States is the availability of adequate pediatric health care in their community. Community leaders attempting to recruit health care providers and pediatricians considering locating their practice in a specific community need a method by which they can evaluate a community's potential for supporting a new primary care practice. A detailed survey was conducted in early 1988 of pediatric practices geographically dispersed throughout the state of Oklahoma. Data collected from the physicians and their administrative staff reflected the volume of office and hospital visits and practice costs over the prior 12 months. Using the capital costs and direct operating cost data with information obtained on the number of patient visits and revenue generated collected in this survey, we designed a model to project the economic feasibility of establishing a pediatric practice in a specific community. This model can be used to project the number of annual pediatric primary care visits a community can generate, the direct and indirect costs to establish and maintain a clinic, and the gross revenue and net income of the practice.

Adolescent↗
PubMed1989

8;21 translocation in myelodysplasia secondary to essential thrombocythemia.

A case is presented of a 73-year-old woman who received busulphan for essential thrombocythemia and subsequently developed a myelodysplastic syndrome (MDS), which transformed to acute nonlymphoblastic leukaemia within 1 month. Cytogenetic studies showed a 46,XX,t(8;21) (q22;q22) karyotype in all metaphases examined at diagnosis. The karyotypic abnormality is previously unreported in secondary myelodysplasia and may have specific clinical implications in this setting, such as early transformation to acute leukaemia and short survival. This finding contrasts with the generally favourable prognosis of the 8;21 translocation in patients with de novo acute nonlymphoblastic leukemia. A possible explanation for this difference may be the involvement of a committed progenitor in acute nonlymphoblastic leukaemia, while in myelodysplasia the more primitive multipotent stem cell may be affected.

Aged↗