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Biomedical subjects

J Chapman

Publications and source records attributed to J Chapman.

At least 379 records · Page 21Linked to original sources
PubMed1988

Antibodies to ganglioside GM1 in patients with Alzheimer's disease.

Gangliosides are thought to have a role in neuronal development and regeneration while anti-ganglioside antibodies have been shown to impair these processes. In the present work we examined whether the neuronal degeneration in Alzheimer's disease is associated with the presence of anti-ganglioside antibodies. A significant level of antibodies specific to ganglioside GM1 but not to other gangliosides (GD1a, GD1b, GT1b and GQ1b) was found in patients with Alzheimer's disease as compared to normal age matched controls. A high level of antibodies to GM1 was also found in patients with multi-infarct dementia and Parkinson's disease with dementia but not in non-demented patients with other neurodegenerative diseases. These results may reflect a specific change in ganglioside metabolism which is associated with the neurodegenerative processes underlying Alzheimer's disease and other causes of dementia.

Adult↗
PubMed1988

Cytochemical methods for the localization of invertase activity in plant tissues.

Two cytochemical methods for the localization of acid and alkaline invertases are given. The first is based upon the reduction of a silver complex at two different pH ranges, whilst the second is based upon the tetrazolium reaction and permits quantification of the rate of activity of alkaline invertase activity. The distribution of alkaline invertase activity throughout the root apex of Pisum sativum and the cell wall localization of acid invertase for material excised from tuber tissue of Helianthus tuberosus are both confirmed.

Glycoside Hydrolases↗
PubMed1988

Multiple sclerosis: effects of activated T-lymphocyte-derived products on organ cultures of nervous tissue.

Supernatants from multiple sclerosis (MS) T-lymphocytes cause damage to both myelin and glial cells in cerebellar cultures assessed visually and by radiolabel release. Control T-lymphocytes, even after phytohaemagglutinin (PHA) stimulation, yielded supernatants which induced only slight damage, and at later times patients with other neurological diseases (OND) gave variable results. These differences suggest that MS T-lymphocytes are pre-activated in vivo to produce demyelinating factors while control T-lymphocytes are not pre-activated to the same extent. The visual evidence of activation of cerebellar macrophage-like cells was a common finding after MS T-lymphocyte supernatant treatment but there was no correlation with the severity of demyelination. There was a positive correlation between the percentage IL-2 receptor-bearing lymphocytes and the degree of supernatant-induced in vitro demyelination.

B-Lymphocytes↗
PubMed1988

Recurrent diabetic ketoacidosis.

In a study over 15 years, 740 episodes of diabetic ketoacidosis occurred in 505 patients. A total of 113 patients had more than one episode. The majority (90%) of recurrences were within 4 years of the initial episode. Taking a definition of recurrent ketoacidosis as three or more episodes within 4 years, 39 patients were identified. Two subgroups appeared prone to such frequent recurrences, namely girls less than 20 years of age and women more than 59 years of age. A variety of causes of recurrent episodes was noted in the young patients but in the older patients other chronic illnesses complicated the diabetes. The need for good domiciliary supervision of elderly chronic sick patients who require insulin is emphasized.

Diabetic Ketoacidosis↗
PubMed1988

Antibodies to cholinergic neurons in Alzheimer's disease.

Alzheimer's disease (AD) is associated with degenerative changes in nuclei of the basal forebrain which provide most of the cholinergic input to the cortex and hippocampus and with a reduction in presynaptic cholinergic parameters in these areas. Although the etiology and pathogenesis of AD are not known, several reports indicate the involvement of immunological mechanisms. In the present work we examined the existence of antibodies in sera of AD patients that bind specifically to cholinergic neurons. As antigens we employed the purely cholinergic electromotor neurons of the electric fish Torpedo which are chemically homogeneous and cross-react antigenically with human and other mammalian cholinergic neurons. Our findings show that immunoglobulins from sera of AD patients bind to a specific antigen (molecular mass 200 kilodaltons) in the cell bodies and axons of Torpedo electromotor neurons and that the levels of such antibodies are significantly higher in AD patients than in controls. The possible role of these antibodies in the cholinergic dysfunction in AD and their diagnostic potential are discussed.

Aged↗
PubMed1988

Locally advanced adenocarcinoma of the breast without distant metastasis treated with multimodal therapies.

Locally advanced breast cancer has been treated with a variety of primary treatments with or without adjuvant therapies. This study combines radiation, chemotherapy, and surgery as a multimodal program for Stage III breast cancer. Radiation was started on day 1: 4600 rad were administered to the breast and 4500 rad were administered to the axilla and supraclavicular areas. Chemotherapy was started on day 1 with weekly intravenous injections of 5-fluorouracil (5FU) (300 mg/m2), methotrexate (15 mg/m2), vincristine (0.625 mg/m2), oral cytoxan (60 mg/m2), and prednisone (30 mg/m2 for two weeks, then 20 mg/m2 for two weeks, then 10 mg/m2 for two weeks). The 5FU, methotrexate, and cytoxan were given for 10 months postsurgery. This combination of modalities produced a complete remission in all 13 patients with Stage III breast cancer after two months of therapy. The median disease-free period was two years. The median survival was 44 months. This approach to the management of Stage III breast cancer is worthy of further investigation.

Adenocarcinoma↗
PubMed1987

Is changing hypothalamic activity important for control of ovulation?

The activity of the hypothalamic gonadotrophin releasing hormone pulse generator in women with regular ovulatory and anovulatory menstrual cycles was assessed to see whether changes therein are important determinants of normal and impaired ovarian function. Endogenous gonadotrophin releasing hormone secretion was inferred by measurement of the pituitary luteinising hormone response by characterisation of pulsatile luteinising hormone release over eight hours on three occasions during the course of follicular development and once during the luteal stage of the same cycles. In 13 ovulatory cycles (serum progesterone concentration greater than 25 nmol/l) confirmed by ovarian ultrasonography a pronounced variability in luteinising hormone pulse patterns among subjects was compatible with ovulation. In the luteal stage of ovulatory cycles the luteinising hormone interpeak interval (85 min, range 42-125) was significantly longer than that during the early follicular (64 min, 40-103), mid-follicular (62 min, 37-107), and late follicular (59 min, 39-80) stages of the same cycles. Thus in ovulatory cycles no increase in frequency of the gonadotrophin releasing hormone pulse generator was detected during follicular development, though this activity decreased in the luteal stage. In five late follicular stage studies in which part of the preovulatory luteinising hormone surge was captured no change in pulse frequency of luteinising hormone was detected compared with the mid-follicular stage of the same cycles or when compared with the late follicular stage of other cycles when no luteinising hormone surge was captured. Though mean luteinising hormone concentrations in luteinising hormone surge series (36 IU/l) were high, the amplitude of luteinising hormone pulses (165%) was only slightly greater than during non-surge late follicular stage studies (145%). Hence no change in hypothalamic gonadotrophin releasing hormone activity is required to generate the preovulatory discharge of luteinising hormone in man, which occurs as a result of the sensitising action of rising oestradiol concentrations on pituitary responsiveness to the same hypothalamic input signal. Luteinising hormone pulse frequency, peak amplitude, and mean serum luteinising hormone concentrations in seven anovulatory cycles (progesterone concentration less than 10 nmol/l) were not different from those at comparable stages of ovulatory cycles. These data suggest that the primary abnormality in this group of regularly menstruating anovulatory women lies in the ovary rather than in the hypothalamic control of the anterior pituitary.

Adult↗
PubMed1987

Quantification of human apolipoprotein E in plasma and lipoprotein subfractions by a non-competitive enzyme immunoassay.

A non-competitive enzyme linked immunosorbent assay (ELISA) has been developed to quantitate apolipoprotein E (Apo E) concentrations in serum and in isolated lipoproteins. Microtiter plates coated with affinity-purified antibodies to Apo E were used and the Apo E bound to the plates was estimated with peroxidase-labelled antibodies to Apo E. The average concentration of Apo E in the serum from normolipidemic subjects (n = 132) was 54 +/- 19 mg/l. The within and between assay coefficients of variation were 4.65 and 7.08%, respectively. The standard curves for Apo E in serum, in VLDL and in HDL were parallel. There was a good correlation (r = 0.81) between estimation of Apo E by our assay and that by electroimmunoassay. Assay sensitivity (1 ng of Apo E) was sufficient to enable a study of the distribution of Apo E in plasma lipoproteins separated by density gradient ultracentrifugal fractionation.

Apolipoproteins E↗
PubMed1987

Certain social considerations in abandoning high technology medical imaging.

The growth in medical costs has created significant public concern and has appeared to mandate health care policy changes of great magnitude. These important policy decisions will evoke changes that could alter the traditional relationship in health care and will significantly affect the activities of both consumers and providers. This article will address one of the major areas affected by these recently instituted health care policies, medical imaging technology.

Cost Control↗
PubMed1987

Epicoccum allergy: skin reaction patterns and spore/mycelium disparities recognized by IgG and IgE ELISA inhibition.

Comparable degrees of skin reactivity were observed towards spore and mycelium extracts from two isolates of Epicoccum and to one preparation of Alternaria in 35 rural and 120 university patients. The best experimental extracts detected Epicoccum sensitivity in 70% of the group tested while the commercial extract detected sensitivity in only 6%. Skin reaction correlations were greatest within isolates (eg, spore-A/mycelium-A), then for specific fungus parts (eg, spore-A/spore-B), then between isolates and parts (spore-A/mycelium-B). High correlations were found between individual IgG and IgE ELISA values for all antigens using serum from Epicoccum skin-reactive patients. ELISA inhibition results suggested that significant cross-reactivity exists between Epicoccum and Alternaria antigens recognized by IgG but not by IgE. ELISA inhibition cross-reaction patterns among Epicoccum antigens were comparable to skin reactions while IgG patterns showed little variability. Further characterization of spore/mycelium and interstrain recognition patterns among different immunoglobulin isotypes will be necessary before complete standardization of extracts from different parts of fungi will be possible. The use of spore material for skin testing and treatment of Epicoccum sensitivity appears to be both premature and unnecessary at this time.

Enzyme-Linked Immunosorbent Assay↗