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Biomedical subjects

J Richards

Publications and source records attributed to J Richards.

At least 127 records · Page 7Linked to original sources
PubMed1990

Disseminated zygomycosis and systemic lupus erythematosus.

A young woman with long-standing systemic lupus erythematosus and rheumatic fever presented with deteriorating renal function. She had severe gastritis treated with cimetidine and received methylprednisolone when her blood cultures were repeatedly negative. She developed spontaneous bruising and bleeding from venepuncture sites, leading to clotting studies and a diagnosis of thrombotic thrombocytopenic purpura. At post-mortem, extensive evidence of disseminated zygomycosis was found. The likely portal of entry was the gastric route.

Adult↗
PubMed1990

A novel oncofetal gene is expressed in a stage-specific manner in murine embryonic development.

A novel cDNA clone obtained from a murine T-lymphoma library hybridizes to transcripts expressed in placenta and embryos (Pem) in a stage-specific manner. The Pem cDNA sequence predicts an intracellular hydrophilic protein with no significant sequence similarity to other DNA or protein sequences. Pem transcripts are abundant in 7- and 8-day mouse embryos, but decrease precipitously thereafter. On Day 9 they become abundant in placenta and yolk sac, persisting there until parturition. Although Pem transcripts are present in immortalized and tumorigenic cell lines from several different cell lineages, they are not detectable in any of 15 adult tissues tested. The expression of Pem during fetal development and its presence in immortalized and neoplastic cell lines is consistent with the properties expected of an "oncofetal" gene.

Amino Acid Sequence↗
PubMed1990

The repeated sequence CATT(A/T) is required for granulocyte-macrophage colony-stimulating factor promoter activity.

The hematopoietic growth factor GM-CSF (granulocyte-macrophage colony-stimulating factor) is expressed by activated but not resting T lymphocytes. Previously, we localized GM-CSF-inducible promoter activity to a 90-bp region of GM-CSF 5'-flanking sequences extending from bp -53 to +37. To more precisely identify the GM-CSF DNA sequences required for inducible promoter activity in T lymphocytes, we have performed mutagenesis within a region of GM-CSF 5'-flanking sequences (bp -57 to -24) that contains the repeated sequence CATT(A/T). Mutations that do not alter the repeated CATT(A/T) sequence do not eliminate inducible promoter activity, whereas mutation or deletion of either of the CATT(A/T) repeats eliminates all inducible promoter activity in T-cell lines and in primary human T lymphocytes. Thus, both copies of the direct repeat CATT(A/T) are required for mitogen-inducible expression of GM-CSF in T cells.

Animals↗
PubMed1990

Microbiology, chemotherapy and mortality of brain abscess in Newcastle-upon-Tyne between 1979 and 1988.

71 patients admitted to Newcastle Regional Neurosurgical Centre between 1979 and 1988 with a diagnosis of brain abscess are reviewed. The overall mortality was 9.9%, with an operative mortality of 7%. The bacteriology of these abscesses is discussed in detail, together with the importance of effective standardized antimicrobial treatment regimens. The low mortality figures appeared to be in direct relationship to early recognition of this condition, prompt surgical intervention and effective chemotherapy.

Ampicillin↗
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

Cognitive networking as a learning strategy.

A concept map, concept network, or hierarchical concept tree is an instructional tool which graphically arranges information to help students build better mental connections among concepts. The ability to retain and recall concepts by building such mental connections is called cognitive networking. In the pilot study described here, we tested whether this arrangement of graphics could enhance senior medical technology students' ability to create effective cognitive networks on bacterial features. The self-instructional slide/tape program we designed made use of the graphics to show the relationships among general and specific bacterial features. Students who viewed the slide/tape and used the graphics when studying for the exam performed significantly better on objectives illustrated on the slide/tape than did the previous class which did not view the graphics. There was no significant difference between the two groups on objectives which were the base from which the graphics were built.

Cognition↗
PubMed1989

Electrophysiological analysis of dopamine cells from the substantia nigra pars compacta of circling rats.

Extracellular single unit recordings were obtained from dopamine cells in the substantia nigra pars compacta during forced locomotion on a circular turntable treadmill. Stainless steel wire electrodes, 18 microns diameter, insulated with Parylene C were used. During the entire recording session the rat was in the treadmill apparatus. The device was stopped while a cell was being sought. A cell was identified as dopaminergic by a frequency of 3 to 10 Hz and a biphasic or triphasic action potential of greater than 2 ms in duration. An attempt was made to record from cells under the following conditions: animal at rest, animal turning in one direction, at rest again, turning in the opposite direction and finally, at rest. If the cell was still firing after these recordings, haloperidol was injected i.p. to see that the presumed dopamine cell increased its firing rate. A cell was held for all the observations in 4 animals. In an additional 10 rats, recordings were made before, during and after movement in one direction. Three animals were recorded only before and during movement. In 6 of the total of 17 animals haloperidol was administered. Results showed that firing patterns of cells in awake animals were similar to those reported from dopamine cells of anesthetized rats. During either contralateral or ipsilateral turning the firing frequency and burst activity significantly increased. These results indicate that the activity of dopamine cells in substantia nigra is increased bilaterally during circling.

Action Potentials↗
PubMed1989

A conjecture on the interface mechanics in fractures based on the interpretation of impulse vests.

Time-domain tests for monitoring fracture healing, undertaken by the authors and workers elsewhere, show a repeatable characteristic signal behaviour which is difficult to explain using the linear models prevailing in biomechanics. The paper proposes a simple non-linear model which, it is believed, will reproduce the observed signal behaviour and is consistent with the biphasic stiffness model previously identified in static mechanical testing for monitoring of fracture healing. This, in turn, correlates with the two stages of callus formation in the accepted biological model.

Biomechanical Phenomena↗
PubMed1989

Respiratory distress during total parenteral nutrition.

We report on a patient who developed fatal respiratory distress two days after starting parenteral feeding for malnutrition complicating Crohn's disease. Post mortem examination revealed pulmonary collapse secondary to mediastinal leak of the infusion fluid due to an undiagnosed erosion of the vascular catheter tip through the brachiocephalic vein.

Aged↗
PubMed1988

Phorbol ester-induced G2 delay in HeLa cells analyzed by time lapse photography.

The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) has been shown previously to mimic X-irradiation in altering cell cycle parameters in Hela cells [Kinzel, V., Richards, J., and Stöhr, M., Science (Wash. DC), 210: 429-431, 1980]. These changes include a delay in G2 phase from which cells recover in the presence of TPA, which suggests an involvement of cellular mediators. In order to obtain information on the onset and the duration of the G2 delay, as well as the onset and rate of recovery, a time-lapse study has been carried out. The analysis of cells in prophase shows that at 10(-6) M and 10(-7) M concentrations, TPA and 12-O-retinoylphorbol-13-acetate (RPA) cause a G2 delay which lasts on the order of 3.5 to 4 h. Below 10(-7) M of RPA and below 10(-8) M of TPA a clear-cut inhibition of HeLa cells in G2 is no longer detectable by this method. These results for a given phorbol ester are dose dependent within a certain range but unlike the case of X-rays are not proportional to dose. Within the dose range studied the recovery rate follows the opposite order. At 10(-6) M TPA and RPA an indication of a parasynchronous burst is observed. At smaller concentrations or with less biological activity of phorbol ester, the cell multiplication rate approaches that of the control or remains even smaller. Possible reasons are discussed. The determination of the transition points seems to indicate that the cellular events inhibited in G2 occur shortly before visible prophase.

Cell Cycle↗