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Biomedical subjects

J Swift

Publications and source records attributed to J Swift.

At least 19 recordsLinked to original sources

Paranodal pathology in Tangier disease with remitting-relapsing multifocal neuropathy.

Pathological studies of a sural nerve biopsy in a man with Tangier disease presenting as a remitting-relapsing multifocal neuropathy showed abnormalities in the paranodal regions, including lipid deposition (65%) and redundant myelin foldings, with various degrees of myelin splitting and vesiculation (43%) forming small tomacula and abnormal myelin terminal loops (4%). The internodal regions were normal in the majority of myelinated fibres. Abnormal lipid storage was also present in the Schwann cells of the majority of unmyelinated fibres (67%). The evidence suggests that the noncompacted myelin region of the paranode is a preferential site for lipid storage in the myelinated Schwann cell, and that the space-occupying effects of the cholesterol esters leads to paranodal malfunction and tomacula formation as the pathological basis for the multifocal relapsing-remitting clinical course.

Adolescent↗

A novel method for correlating internal and external structure of individual myelinated nerve fibres.

A new method is described that enables longitudinal and cross sections of an individual nerve fibre to be cut at multiple specified sites along the fibre by the use of a unique marker system. In this way the internal structure of the fibre can be correlated with the external appearance. Individual myelinated nerve fibres are teased apart in epoxy resin and mounted onto a carbon-coated slide, and after orientation and marking of specific sites of interest are snap frozen to liberate the orientated and marked fibres for embedding on the surface of an epoxy resin block for subsequent longitudinal or transverse sectioning. This method is particularly useful for the correlative study of the myelin-axon relationships.

Axons↗

Focal myelin swellings and tomacula in anti-MAG IgM paraproteinaemic neuropathy: novel teased nerve fiber studies.

Focal myelin swellings and tomacula in teased nerve fibers from a case of IgM anti-myelin-associated glycoprotein (MAG) paraproteinaemic neuropathy were examined using a novel technique. Five different morphologic abnormalities were identified--myelin sheath outfolding, myelin sheath infolding, enlargement of the adaxonal space, myelin degeneration, multiple increased concentric loops--and a combination of these structural abnormalities often occur in association with myelin degeneration. Similar structural changes were found in externally normal segments of teased fibers without evidence of myelin swelling or tomacula from the same case. These structural abnormalities are consistent with a disturbance of the normal adhesion functions of MAG in the maintenance of axon-myelin relationships.

Aged↗

EASY--an Expert Analysis SYstem for interpreting database search outputs.

With the ever-increasing need to handle large volumes of sequence data efficiently and reliably, we have developed the EASY system for performing combined protein sequence and pattern database searches. EASY runs searches simultaneously and distils results into a concise 1-line diagnosis. By bringing together results of several different analyses, EASY provides a rapid means of evaluating biological significance, minimising the risk of inferring false relationships, for example from relying exclusively on top BLAST hits. The program has been tested using a variety of protein families and was instrumental in resolving family assignments in a major update of the PRINTS database.

Computational Biology↗

Benefits of osteopathic manipulative treatment for hospitalized elderly patients with pneumonia.

While osteopathic manipulative treatment (OMT) is thought to be beneficial for patients with pneumonia, there have been few clinical trials--especially in the elderly. The authors' pilot study suggested that duration of intravenous antibiotic use and length of hospital stay were promising measures of outcome. Therefore, a larger randomized controlled study was conducted. Elderly patients hospitalized with acute pneumonia were recruited and randomly placed into two groups: 28 in the treatment group and 30 in the control group. The treatment group received a standardized OMT protocol, while the control group received a light touch protocol. There was no statistical difference between groups for age, sex, or simplified acute physiology scores. The treatment group had a significantly shorter duration of intravenous antibiotic treatment and a shorter hospital stay.

Acute Disease↗

Factors influencing palliative care. Qualitative study of family physicians' practices.

OBJECTIVE: To examine factors that influence family physicians' decisions to practise palliative care. DESIGN: Qualitative method of in-depth interviews. SETTING: Southwestern Ontario. PARTICIPANTS: Family physicians who practise palliative care on a full-time basis, who practise on a part-time basis, or who have retired from active involvement in palliative care. METHOD: Eleven in-depth interviews were conducted to explore factors that influence family physicians' decisions to practise palliative care and factors that sustain their interest in palliative care. All interviews were audiotaped and transcribed verbatim. The analysis strategy used a phenomenological approach and occurred concurrently rather than sequentially. All interview transcriptions were read independently by the researchers, who then compared and combined their analyses. Final analysis involved examining all interviews collectively, thus permitting relationships between and among central themes to emerge. MAIN OUTCOME FINDINGS: The overriding theme was a common philosophy of palliative care focusing on acceptance of death, whole person care, compassion, communication, and teamwork. Participants' philosophies were shaped by their education and by professional and personal experiences. In addition, participants articulated personal and systemic factors currently affecting their practice of palliative care. CONCLUSIONS: Participants observed that primary care physicians should be responsible for their patients' palliative care within the context of interdisciplinary teams. For medical students to be knowledgeable and sensitive to the needs of dying patients, palliative care should be given higher priority in the curriculum. Finally, participants argued compellingly for transferring the philosophy of palliative care to the overall practice of medicine.

Adult↗

Signet-ring carcinoma of the prostate.

A case of prostatic signet-ring adenocarcinoma is described in a man with a history of open prostatectomy for prostate carcinoma (18 years previously). Immunostaining confirmed the prostatic origin of the signet-ring tumor which stained for prostatic acid phosphatase (PSAP) and prostate specific antigen (PSA). Cytokeratin immunostaining showed the vacuoles to be true lamina with clear and distinct outlines, the feature confirmed by ultrastructural examination. This aggressive tumor is an uncommon but distinct variant of primary prostatic carcinoma which should be distinguished from artefactual vacuolation of tumor, inflammatory and stromal cells, and metastatic disease.

Aged↗

Initiation of reverse transcription during cell-to-cell transmission of human immunodeficiency virus infection uses pre-existing reverse transcriptase.

H3B cells, a laboratory clone of H9 cells persistently infected with the HTLV-IIIB strain of human immunodeficiency virus (HIV), contained significant levels of cell-associated reverse transcriptase (RT) activity measured by in vitro assays using either exogenous or endogenous templates. The cell-associated RT activity detected using exogenous template was almost wholly in a soluble (non-sedimentable) form whereas endogenous activity sedimented as a particulate structure associated with viral RNA. Despite this, H3B cells did not contain episomal HIV DNA detectable by Southern blot, indicating that in vivo reverse transcription was not occurring to any significant extent in these cells. However, when susceptible HUT 78 cells were infected by co-cultivation with H3B cells, dramatic synthesis of episomal HIV DNA occurred. Concurrently with this de novo initiation of reverse transcription, however, we found no detectable change in intracellular levels or cleavage profiles of immunoprecipitable RT polypeptides. Finally, actinomycin D pre-treatment of H3B cells to prevent de novo transcription from donor cell proviral DNA after co-cultivation did not affect the initiation of in vivo reverse transcription following cell-to-cell HIV infection. These results demonstrated that cells persistently infected with HIV contained significant fully cleaved cell-associated RT in a form that was active in vitro but not in vivo and that following cell-to-cell transmission of HIV infection to susceptible cells, de novo reverse transcription was initiated without detectable evidence of further synthesis or proteolytic processing of HIV RT. The nature of this initiation process requires further study.

Biological Transport↗

Identification of the microsporidian parasite, Enterocytozoon bieneusi in faecal samples and intestinal biopsies from an AIDS patient.

The microsporidian parasite, Enterocytozoon bieneusi, is currently recognized as a potentially important cause of chronic diarrhoea in patients infected with the human immunodeficiency virus (HIV). Faecal concentrates from a 38-year-old, HIV-seropositive patient examined by light and electron microscopy revealed the presence of numerous microsporidian spores. The structural characteristics of the spores were consistent with those previously described for Enterocytozoon bieneusi. Each spore contained a single nucleus, a posterior vacuole and a polar filament with 6-7 overlapping coils which appeared in cross-section as a series of 3 doublets. Mature spores were surrounded by an inner unit membrane, an electron-lucent endospore and a thin, electron-dense exospore. The identity of the parasite was confirmed by the detection of unique endogenous developmental stages in duodenal biopsies. Both proliferative and sporogonial plasmodia (meronts and sporonts) were observed and all stages were monokaryotic (single nucleus) and apansporoblastic (sporophorous vesicle absent). Proliferative and sporogonial plasmodia divided by plasmotomy and spore organelles (polar filament, attachment disc and polaroplast) were well developed prior to fission of the sporogonial plasmodium.

AIDS-Related Opportunistic Infections↗

Early results of combined electrohydraulic shock-wave lithotripsy and oral litholytic therapy of gallbladder stones at the University of Iowa.

One hundred thirty-three patients were entered into a randomized, double-blind, placebo-controlled trial of extracorporeal shock-wave lithotripsy for symptomatic gallstones versus extracorporeal shock-wave lithotripsy plus adjuvant litholytic therapy with ursodeoxycholic acid (UDCA). Six months after lithotripsy, patients receiving placebo were crossed over to UDCA therapy without unblinding the study. One hundred sixteen patients have completed 6 months of follow-up. Five patients were dropped from the study. Nine percent have required cholecystectomy (11 patients with biliary colic and 1 with acute cholecystitis). Ninety-one patients had a solitary stone (64 patients had stones less than or equal to 20 mm and 27 patients had stones greater than 20 mm in diameter), and 25 patients had two to three stones. Fifty percent were retreated. Cumulative stone-free rates at 6, 12, and 18 months were 26%, 39%, and 41%, respectively. At 6 months there was a significant advantage for patients treated with UDCA versus placebo (36% vs 17% were stone free) that had disappeared by 12 months (placebo-treated patients had received 6 months of UDCA). Patients with solitary stones equal to or less than 20 mm in diameter treated with UDCA had stone-free rates at 6, 12, and 18 months of 58%, 58%, and 62%, respectively, versus 27%, 56%, and 50%. The difference was significant only at the 6- month follow-up. Stone-free rates for patients with large solitary stones and multiple stones were very low. Extracorporeal shock-wave lithotripsy is both safe and effective therapy for treatment of symptomatic gallstones in patients with a solitary stone equal to or less than 20 mm in diameter. UDCA markedly improves the efficiency of the procedure and results in a stone-free gallbladder sooner.

Administration, Oral↗

Release of neuronotrophic factor from rabbit corneal epithelium during wound healing and nerve regeneration.

Epithelial neuronotropic factor (ENF) is secreted by cultured epithelial cells of rabbit cornea and conjunctiva, and is active in promoting survival and inducing neurite outgrowth of cultured trigeminal neurons. This study evaluated the relation of ENF to corneal nerve regeneration utilizing a model of heptanol-induced epithelial wounding. The organ culture technique was used to collect ENF from the intact corneal epithelium, and a neuronal bioassay was utilized to quantify ENF. The results revealed no change in ENF secretion either during initial wound closure or after 1 week, when the epithelium had regenerated. However, ENF secretion was elevated 2.4 times in 2 weeks after wounding. Morphometric analysis of corneal nerves stained by gold chloride impregnation showed that the first sign of regeneration of intraepithelial nerves was observed after 2 weeks, and the normal pattern of epithelial neural density was re-established after 3 weeks. However, the neural density was still subnormal (35-47% less than the control) in the wounded epithelium up to 4 weeks after wounding. Thus it appears that a surge in ENF secretion occurred after epithelial regeneration but before nerve regeneration. The results suggest that ENF may mediate corneal nerve regeneration.

Animals↗

A randomized study of the impact of home health aides on diabetic control and utilization patterns.

Home health aides were offered to half of a group of 227 low-income diabetic clinic patients; in the group offered aides, fasting blood sugar (FBS) declined when compared to control group (10.1 mg/dl vs an increase of 5.1 mg/dl), and missed clinic appointments and emergency room use also decreased. The group of 44, who, upon offer of an aide actually accepted one, showed a significant increase in eye clinic appointments as well as the greatest decline in FBS (13.9 mg/dl).

Adult↗