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Biomedical subjects

J North

Publications and source records attributed to J North.

At least 55 records · Page 3Linked to original sources
PubMed1993

Migraine and migrainous stroke: risk factors and prognosis.

We compared epidemiologic and clinical data from 310 patients with migraine and 30 patients with acute migrainous stroke to identify factors predictive of migrainous stroke and assess the risk of future stroke in these two populations. We found no significant differences in gender ratio or in the frequency of smoking, estrogen use, hypertension, mitral valve prolapse, or family history of migraine between the two groups. A history of migraine with aura was significantly more common in the migrainous stroke group (24 of 30 [80%] versus 142 of 310 [46%]; p < 0.001), as was a history of prior stroke (nine of 30 [30%] versus four of 310 [1.3%]; p < 0.001). We followed 173 of the migraine patients for at least 1 year and a mean of 35.8 months, and no strokes occurred in this group. We followed 28 of the migrainous stroke patients for a mean of 25.3 months, and there were six recurrent strokes in that group, all again migraine-associated. Migrainous stroke is more common in individuals with aura than in those who are aura-free, but this association is of little value in attempting to distinguish patients destined for migrainous stroke from the migraine population at large. Patients with a history of migraine-associated stroke are at significantly increased risk for recurrent stroke.

Acute Disease↗
PubMed1992

Photodynamic inactivation of retrovirus by benzoporphyrin derivative: a feline leukemia virus model.

The ability of a photosensitizer, benzoporphyrin derivative monoacid ring A (BPD-MA), and either broad-spectrum (400-1200 nm) or narrow-band (600-700 nm) red light to kill feline leukemia virus (FeLV) and FeLV-infected cat T cells (cell line 3201) was investigated in culture medium containing fetal calf serum and in blood from infected cats. A molecular clone of FeLV, 61E, is minimally pathogenic and productively infects 3201 cells while causing no change in rate of cell division, viability, or size. Active virus (either free or within infected cells) was quantified by using a limiting dilution assay that involved cocultivation of test samples with naive 3201 cells, after which either the polymerase chain reaction or a reverse transcriptase assay was used to detect the presence of virus. It was shown that 61E-infected T cells in culture were slightly more sensitive to photodynamic killing than were uninfected cells. Infected cells and free virus were eliminated from whole blood taken from infected cats by using 4 micrograms per mL of BPD-MA and 40 J per cm2 of red light. These results correlate well with previous results with BPD-MA and vesicular stomatitis virus in whole human blood and suggest that this photosensitizer is a promising agent for the elimination of retroviruses that are either free or located within infected cells in blood.

Animals↗
PubMed1992

Viral inactivation in blood and red cell concentrates with benzoporphyrin derivative.

Using both the vesicular stomatitis virus (VSV) and feline leukemia virus (FeLV) as models we have shown that the photosensitizer benzoporphyrin derivative ring A (BPD), when activated with red light (600-700 nm), is effective in eliminating both free virus and virally infected cells from spiked blood products and whole blood drawn from viremic cats experimentally infected with FeLV, under conditions which appear to share red blood cells. The effect of photodynamic therapy on infected lymphocytes, as visualized by scanning electron microscopy, initially appeared as a limited area of tiny holes in the membrane. These holes were subsequently seen to increase in size until the membrane appeared completely decomposed. The red cell membranes however, seem to be undamaged by such photodynamic treatment.

Animals↗
PubMed1990

Isolation and EBV-transformation of a minor population of normal human tonsillar B cells bearing a cold agglutinin-associated idiotope.

Human autoantibodies which bind to red blood cells and cause agglutination in the cold, collectively comprise the cold agglutinins: a subset of these antibodies with specificity for the Ii carbohydrate antigen on the red cell surface bears cross-reacting idiotypic determinants. A monoclonal antibody has been raised which specifically inhibits the cold agglutination reaction, and has been used to probe normal lymphoid cell populations for the presence of B cells expressing the same idiotope. Although such cells comprise only 1-2% of the lymphoid cells in the tonsil, it has been possible to isolate them in good yield and purity using the antibody and magnetic beads. Released cells were infected with the Epstein-Barr (EB) virus and an idiotope-bearing line established. The IgM secreted by the line was found to agglutinate red cells in the cold indicating that cold agglutinin-producing cells were among this idiotope-positive population. The immunophenotype of the line, and the agglutinating power of the secreted IgM, have been compared with a similarly immortalized idiotope-bearing line established from neoplastic B cells of a patient with frank cold agglutination disease.

Agglutinins↗
PubMed1990

Good systems save costs.

The costs in medical practices are high because of the need for personal contact with patients. It is important, therefore, to minimise other costs by the use of good systems. One such system is the Health Record, which is essential in every practice, and if it is the appropriate system it can significantly reduce ongoing costs. Similarly, good financial and accounting systems and efficient appointment systems can also reduce practice costs.

Forms and Records Control↗
PubMed1990

The importance of minutes, contracts and agreements.

Hardly a day passes in the office of the RACGP Services Division without an enquiry from a general practitioner about an employment contract. These contracts are as important as our health records but unfortunately are poorly attended to and often missing from the office files. A little attention can save a lot of anguish.

Contract Services↗
PubMed1989

Identification of normal B-cell counterparts of neoplastic cells which secrete cold agglutinins of anti-I and anti-i specificity.

A monoclonal antibody, which recognizes a cross-reacting idiotypic determinant present on human cold-reactive autoantibodies with anti-I or anti-i binding activity, has been found to specifically inhibit the cold agglutination of red cells. This suggests that an epitope close to the binding site of such autoantibodies is being recognized. The antibody has been used to identify tumour cells in the blood of three patients with cold haemagglutinin disease, and to analyse the heterogeneous nature of the neoplastic B-cell clone present in the bone marrow of one of the patients. Using S-phase analysis, it was found that cell proliferation was occurring in the bone marrow but not in the blood, and that the major proliferating population was that of lymphoplasmacytoid cells containing large vesicular inclusions of idiotypic IgM. It has also been possible to locate normal B-cells which are recognized by the anti-idiotypic antibody. Such cells have been found throughout the normal adult lymphoid tissue where they account for 2.9-10.8% of the B lymphocyte population. They are also present in fetal spleen at 15 weeks gestation, indicating that immunoglobulins bearing this sequence form part of the immature B-cell repertoire.

Agglutinins↗
PubMed1989

Are you master or servant of the telephone?

With good organisation, the telephone is a very useful tool in general practice, but if not controlled, it can become master rather than servant. Involvement in its use in your practice is important.

Humans↗
PubMed1989

Turn account settlement into a PR exercise.

In general practice it will cost 20 to 25 per cent of the average consultation fee to collect the fee by sending accounts. One might well ask the question: Who can afford to lose that amount of the present consulting fee and still survive economically? At the same time as the fee settlement, the receptionist can help the patient and aid practice efficiency.

Fees, Medical↗
PubMed1989

Is your most valuable resource ignored?

Receptionists are important for the efficient functioning of a practice. They are the eyes and ears of the practice and become a most valuable resource. There should be both formal and informal mechanisms for them to feed back information to the practice decision makers if better practice performance is to be achieved.

Communication↗
PubMed1989

Patient recall.

The RACGP Standards for Computerised Medical Records give guidelines on computer use in Preventive Health Care including opportunistic prompting and recall. Several computer software programmes can handle these activities and make prompting and recall a simple and rewarding task. Unfortunately computer use in this area is not yet widespread so the RACGP is introducing a manual recall facility, as part of the Health Record System, to assist general practitioners to introduce this important aspect of health care delivery.

Computer Systems↗
PubMed1988

Identification of a T cell subset using a rabbit antibody raised against a T suppressor molecule.

Rabbit antiserum to a unique component of an Ag-binding Ts-factor was generated by repeated immunization with purified 30-kDa protein isolated from Fd11 Ts factor (11). This antiserum (anti-p30) was shown to recognize cell surface determinants expressed on the Ts hybridomas Fd11 and A10 but not the fusion partner BW5147. Furthermore, this antiserum was shown to bind to approximately 4% of thymocytes and 10% of nylon wool-purified splenic T cells from all strains of mice tested. Sorting nylon wool-purified T cells from DBA/2 mice for the CD4+ and CD8+ subsets revealed both populations contained cells that bound anti-p30. In addition, when CD4-8- thymocytes were examined for anti-p30 labeling, it was found that about 30% of this enriched population also expressed p30 molecules. In a functional study, anti-p30 was able to neutralize the suppressive effects of Fd11 on a specific assay for in vitro antibody synthesis against ferredoxin.

Animals↗