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Biomedical subjects

A C Logan

Publications and source records attributed to A C Logan.

9 recordsLinked to original sources
PubMed2001

Chronic fatigue syndrome: neurological findings may be related to blood--brain barrier permeability.

Despite volumes of international research, the etiology of chronic fatigue syndrome (CFS) remains elusive. There is, however, considerable evidence that CFS is a disorder involving the central nervous system (CNS). It is our hypothesis that altered permeability of the blood-brain barrier (BBB) may contribute to ongoing signs and symptoms found in CFS. To support this hypothesis we have examined agents that can increase the blood-brain barrier permeability (BBBP) and those that may be involved in CFS. The factors which can compromise the normal BBBP in CFS include viruses, cytokines, 5-hydroxytryptamine, peroxynitrite, nitric oxide, stress, glutathione depletion, essential fatty acid deficiency, and N-methyl-D-aspartate overactivity. It is possible that breakdown of normal BBBP leads to CNS cellular dysfunction and disruptions of neuronal transmission in CFS. Abnormal changes in BBBP have been linked to a number of disorders involving the CNS; based on review of the literature we conclude that the BBB integrity in CFS warrants investigation.

Blood-Brain Barrier↗
PubMed2001

Chronic fatigue syndrome: oxidative stress and dietary modifications.

Chronic fatigue syndrome (CFS) is an illness characterized by persistent and relapsing fatigue, often accompanied by numerous symptoms involving various body systems. The etiology of CFS remains unclear; however, a number of recent studies have shown oxidative stress may be involved in its pathogenesis. The role of oxidative stress in CFS is an important area for current and future research as it suggests the use of antioxidants in the management of CFS. Specifically, the dietary supplements glutathione, N-acetylcysteine, alpha-lipoic acid, oligomeric proanthocyanidins, Ginkgo biloba, and Vaccinium myrtillus (bilberry) may be beneficial. In addition, research on food intolerance is discussed, since food intolerance may be involved in CFS symptom presentation and in oxidation via cytokine induction. Finally, recent evidence suggests celiac disease can present with neurological symptoms in the absence of gastrointestinal symptoms; therefore, celiac disease should be included in the differential diagnosis of CFS.

Antioxidants↗
PubMed1997

Idiopathic myelofibrosis (agnogenic myeloid metaplasia) in a marmoset (Callithrix jacchus): hematologic and histopathologic changes.

Idiopathic myelofibrosis (IMF), or agnogenic myeloid metaplasia, was diagnosed in a sexually mature male marmoset (Callithrix jacchus) based on the results of hematology and histopathologic evaluation of the bone marrow. The hematologic changes included pancytopenia, leukoerythroblastosis, anisocytosis, poikilocytosis, and giant platelets. Histopathologic evaluation of the bone marrow showed marked widespread fibrosis replacing hematopoietic cells and the presence of atypical megakaryocytes. In addition, slight multifocal osteolysis with an increase in serum alkaline phosphatase activity was observed. We believe this is the first report of IMF in a nonhuman primate species.

Animals↗
PubMed1996

Mucociliary function in patients with nasal polyps.

Patients with nasal polyposis complain of nasal blockage and rhinorrhoea, which may be due to impaired mucociliary clearance. The saccharine clearance time and ciliary beat frequency of samples of ciliated epithelium from patients with nasal polyps was measured. We also studied the effect of fluid from the oedematous stroma of nasal polyps and of histamine and prostaglandin (PG) D2, E2 and F2 alpha on the cilia from normal individuals. Polyp fluid was found to increase ciliary beat frequency. Histamine and PGD2 had no effect, but PGE2 and PGF2 alpha both increased ciliary beat frequency and so may cause the ciliostimulatory effect of polyp fluid. The saccharine clearance time was prolonged in three of nine patients, but ciliary beat frequency was only slightly reduced in one of these. Thus, where mucociliary clearance is reduced, it is likely to be due to abnormalities of mucus rather than impaired ciliary activity.

Cilia↗
PubMed1995

The effect of temperature on nasal ciliary beat frequency.

Using a photometric method of measuring ciliary beat frequency, the effect of temperature on ciliary activity was investigated. A linear increase in ciliary beat frequency between 19 degrees and 32 degrees C was found. Between 32 degrees and 40 degrees a plateau was reached in which temperature did not significantly affect frequency and above 40 degrees C the frequency began to decline. It is concluded that nasal cilia are not critically dependent upon temperature in the range 32 degrees and 40 degrees C, the temperature range in which this tissue normally operates.

Adult↗
PubMed1991

Use of Peyer's patch and lymph node fragment cultures to compare local immune responses to Morganella morganii.

Lymphoid tissue fragment cultures were established to analyze the differentiative processes among B cells in Peyer's patches (PP) and peripheral lymph nodes (PLN), especially those in germinal centers. PP cultures from both conventionally reared mice and formerly germ-free mice colonized with Morganella morganii could be maintained for greater than 12 days with continued B-cell division, especially among cells binding high levels of peanut agglutinin, a characteristic of germinal center cells. PLN cultures from conventionally reared mice injected with a heat-killed vaccine of M. morganii could be maintained for the same amount of time. Over this period, PP cultures continued to secrete immunoglobulin A (IgA) as well as smaller amounts of IgM. PP cultures from formerly germ-free mice colonized with M. morganii showed net increases of IgA antiphosphocholine (anti-PC) antibodies with avidities as high as those of the prototypic T15 monoclonal antibody. Similar PLN fragment cultures from conventionally reared mice given footpad injections of M. morganii showed net increases of IgM and IgG anti-PC antibodies in the culture fluid. Thus, although M. morganii stimulated lymphoid tissues in vivo to produce an anti-PC response in vitro when given by either the oral or the parenteral route, the antibody isotypes differed between PP and PLN fragment cultures. Fragment culturing may offer a complementary and simpler way to detect a local secretory IgA response than does either measuring IgA antibody in secretions or detecting IgA antibody in the cytoplasm of plasma cells in the lamina propria of gastrointestinal or respiratory tissue.

Animals↗
PubMedDate not supplied

Clinical pathologic changes in two marmosets with wasting syndrome.

Two sexually mature marmosets (Callithrix jacchus) showing clinical signs similar to those seen in wasting marmoset syndrome (weight loss, decreased muscle mass, and alopecia) were evaluated for clinical and anatomic pathologic changes. The most prominent clinical pathologic alterations included macrocytic normochromic anemia, hypoproteinemia, hypoalbuminemia, elevated serum aspartate aminotransferase and alkaline phosphatase levels, and previously unreported changes of thrombocytosis. The principal gross and histopathologic finding was chronic colitis, which appeared to be the most important contributing factor to the development of wasting syndrome in these marmosets.

Animals↗