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Biomedical subjects

P L Moriearty

Publications and source records attributed to P L Moriearty.

At least 19 recordsLinked to original sources
PubMed1999

Metrifonate increases neuronal excitability in CA1 pyramidal neurons from both young and aging rabbit hippocampus.

The effects of metrifonate, a second generation cholinesterase inhibitor, were examined on CA1 pyramidal neurons from hippocampal slices of young and aging rabbits using current-clamp, intracellular recording techniques. Bath perfusion of metrifonate (10-200 microM) dose-dependently decreased both postburst afterhyperpolarization (AHP) and spike frequency adaptation (accommodation) in neurons from young and aging rabbits (AHP: p < 0.002, young; p < 0.050, aging; accommodation: p < 0.024, young; p < 0.001, aging). These reductions were mediated by muscarinic cholinergic transmission, because they were blocked by addition of atropine (1 microM) to the perfusate. The effects of chronic metrifonate treatment (12 mg/kg for 3 weeks) on CA1 neurons of aging rabbits were also examined ex vivo. Neurons from aging rabbits chronically treated with metrifonate had significantly reduced spike frequency accommodation, compared with vehicle-treated rabbits. Chronic metrifonate treatment did not result in a desensitization to metrifonate ex vivo, because bath perfusion of metrifonate (50 microM) significantly decreased the AHP and accommodation in neurons from both chronically metrifonate- and vehicle-treated aging rabbits. We propose that the facilitating effect of chronic metrifonate treatment on acquisition of hippocampus-dependent tasks such as trace eyeblink conditioning by aging subjects may be caused by this increased excitability of CA1 pyramidal neurons.

Action Potentials↗
PubMed1999

Effects of time and cholinesterase inhibitor treatment on multiple cerebrospinal fluid parameters in Alzheimer's disease.

Development of neuropathology in Alzheimer's disease (AD) cannot be studied directly in living patients. Therefore, concentrations in cerebrospinal fluid (CSF) of the proteins tau, A beta 42, alpha 1-ACT, apoE and other molecules have been analyzed to elucidate their possible role in degeneration and as biomarkers of the disease. To date, however, studies have not analyzed multiple markers in the same patients over time and as a function of pharmacological interventions. In the present investigation we measured CSF tau, A beta 42, alpha 1-ACT, apoE, total protein and electrophoretic fractions, and leukocytes, as well as MMSE, in 12 AD patients of known APOE phenotype. Two or three CSF examinations were performed during periods of up to 2 1/2 years, while subjects were on and off treatment with the cholinesterase inhibitor (ChEI) metrifonate (MTF). CSF A beta 42 and tau levels were in agreement with clinical diagnosis of AD in all patients. Abnormally high proportions of monocytes were found in CSF at baseline, and these proportions correlated positively with plasma alpha 1-ACT and MMSE scores. A small but significant increase in CSF alpha 1-ACT, which correlated with peripheral alpha 1-ACT, was associated with 6 months' MTF treatment, though alpha 1-ACT levels did not change further when treatment continued for 2 years. Monocyte proportions in CSF declined over time in both treated and untreated patients. Among 5 of 6 patients treated for 2 years or more with MTF, CSF measures remained relatively stable. One patient had changes in CSF parameters apparently associated with a transient ischemic attack. Our findings did not indicate that slowed cognitive decline with MTF treatment is associated with systematic change in any CSF marker analyzed. The results suggest that further investigations of the relationship of tau, A beta 42 and cellular abnormalities in CSF early in the course of AD are warranted.

Aged↗
PubMed1998

Effects of metrifonate on cognitive decline in Alzheimer disease: a double-blind, placebo-controlled, 6-month study.

Forty-seven patients with probable Alzheimer disease (AD) completed a 6-month double-blind study to compare metrifonate with placebo. The Alzheimer Disease Assessment Scale cognitive subscale score of the metrifonate group treated to a 50-70% inhibition of red blood cell acetylcholinesterase activity differed significantly from the placebo group score by 1.8 points (p < 0.03) due to a deterioration in cognitive performance in the placebo group (p < 0.01). Statistically significant deterioration also occurred in the Mini-Mental State Examination scores (p < 0.01) in the placebo-treated group. Adverse effects were uncommon and did not require adjustment of the dose of metrifonate or discontinuation of treatment. These findings extend our previous report of a favorable effect of metrifonate on cognitive symptoms in AD by showing clinical, not only statistical, significance.

Aged↗
PubMed1997

Metrifonate treatment enhances acquisition of eyeblink conditioning in aging rabbits.

The cholinergic system is known to show deterioration during aging and Alzheimer's disease. In response, a therapeutic approach to Alzheimer's disease has been to attempt to compensate for the decrease in central cholinergic function by potentiating the activity of the remaining intact cholinergic cells with cholinesterase inhibitors. In this study treatment with the long-lasting cholinesterase inhibitor metrifonate enhanced acquisition of eyeblink conditioning in aging rabbits without producing interfering side effects. The effects of metrifonate on central and peripheral cholinesterase activity were evaluated, as was the involvement of plasma atropine esterase activity on the central and peripheral response to metrifonate. Results demonstrate that metrifonate can produce predictable, dose-dependent ChE inhibition. Associative learning in the aging rabbit was improved by metrifonate-induced steady state ChE inhibition within a range of 30-80%. Metrifonate was behaviorally effective in the absence of the severe side effects which typically plague cholinesterase inhibitors, suggesting that metrifonate is a possible treatment for the cognitive deficits resulting from normal aging and Alzheimer's disease.

Aging↗
PubMed1997

Metrifonate improves associative learning and retention in aging rabbits.

The cholinergic system is known to show deterioration during aging and Alzheimer's disease (AD). In response, a therapeutic approach to AD has been to attempt to compensate for the decrease in central cholinergic function by potentiating the activity of the remaining intact cholinergic cells with cholinesterase (ChE) inhibitors. In this study treatment with the long-lasting ChE inhibitor metrifonate facilitated acquisition and retention of eyeblink conditioning in aging rabbits. Metrifonate treatment resulted in steady-state, dose-dependent acetylcholinesterase (AChE) inhibition in red blood cells. Maximal behavioral efficacy was achieved with AChE inhibition of approximately 40%, with no further improvements resulting from increased levels of inhibition. Metrifonate was behaviorally effective in the absence of the severe side effects that can plague ChE inhibitors, supporting metrifonate as a possible treatment for the cognitive deficits resulting from normal aging and AD.

Acetylcholinesterase↗
PubMed1997

Women's health in the People's Republic of China: some challenges of modernization.

OBJECTIVE: To identify aspects of the health of Chinese women throughout their lifespan which may paradoxically be threatened by modernization and to suggest relevant interventions through medical practice, education and research to meet these challenges. DATA SOURCES: Six risk areas were selected as examples: infant sex ratios; tobacco use by girls; respiratory illness plus anemia; psychosocial stress; osteoporosis; and dementia. Articles and other databases, through article citations, and through consultations with Chinese medical professionals. DATA SELECTION: Studies were selected which described clinical investigations, health care policy, or conditions of women in the People's Republic of China (PRC). Preference (but not exclusivity) was given to articles in internationally available publications, in English, and to authors working in the PRC. DATA EXTRACTION: Study quality, specific descriptive information concerning population, samples, and outcome measures were evaluated. DATA SYNTHESIS: Data documenting the present and future significance of these health threats are described, and current and potential interventions to address these problems through medical practice, education and research are outlined. CONCLUSION: Important issues in women's health are currently recognized in the PRC; problems occur in assigning priorities in the face of a large population and limited resources. The Chinese medical community plays a central role in developing and carrying out interventions to protect and promote women's health.

China↗
PubMed1996

Double-blind, placebo-controlled study of metrifonate, an acetylcholinesterase inhibitor, for Alzheimer disease.

Fifty patients with probable Alzheimer disease (AD) completed a 3-month double-blind study to compare metrifonate to placebo. We dosed metrifonate to achieve a 40-60% inhibition of red blood cell acetylcholinesterase activity. The Alzheimer Disease Assessment Scale cognitive subscale score (ADAS-C) served as the primary outcome measure. At the completion of 3 months of treatment, the metrifonate group ADAS-C score differed significantly from the placebo group score by 2.6 points (p < 0.01). A 0.75-point trend toward improvement occurred during treatment in the ADAS cognitive performance of the metrifonate group (p = 0.15), and a 1.10-point deterioration in cognitive performance was found in the placebo group (p < 0.02). On the Global Improvement Scale (GIS), the two groups differed significantly on their changes from baseline to treatment phase (p < 0.02). Significant deterioration occurred in GIS scores (p < 0.01) and in Mini Mental State Examination (MMSE) scores (p < 0.03) in the placebo-treated group. Adverse effects were uncommon and did not require adjustment of the dose of metrifonate or discontinuation of treatment. We achieved a mean of 52.3% decrease in red blood cell acetylcholinesterase activity. During up to 18 months of subsequent open metrifonate treatment of patients, we found a deterioration of 1.68 points per year in MMSE performance. These findings support further study of the effects of metrifonate on deterioration rate in AD.

Aged↗
PubMed1993

International access to the Chinese medical literature through MEDLINE.

This article reviews, for authors publishing in the Chinese literature, the characteristics of MEDLINE users, the format of MEDLINE citations and the main retrieval strategies used with the system. References were retrieved and data collected through MEDLINE searches of the database 1988-June 1992. Thirty-six indexed journals from the People's Republic of China (PRC) were analyzed. The items of a MEDLINE citation are described. Titles of Chinese journals are listed in English as well as Chinese in the annual "List of Serials Indexed" of Index Medicus. Articles from journals in the PRC are indexed at the China MEDLARS Center, Beijing, PRC. For the 36 journals analyzed, 12,530 citations appeared in MEDLINE during the search period. Basic search strategies are described. Users doing author searches may have difficulties with common Chinese surnames, especially if only one given name initial is used. Journal searches of specialty journals, as well as address field searches for publications from a particular institution, may be helpful to scientists planning a visit to China. Effective use of MEDLINE has become an opportunity and responsibility for scientists and physicians over the world. Suggestions for preparation of English titles and abstracts to assure optimal information transfer and retrieval efficiency are: think about your audience; do not waste words; include key features in the title; be consistent with names and affiliations; use MeSH terms; include important non-MeSH terms in text; use structured abstracts; and obtain MEDLINE printouts of your own citations.

Authorship↗
PubMed1992

Inhibition of human brain and RBC acetylcholinesterase (AChE) by heptylphysostigmine (HPTL).

Heptylphysostigmine (HPTL), a derivative of the AChE inhibitor physostigmine (PHY), is under investigation as a therapeutic agent in Alzheimer's disease. HPTL is active against human RBC AChE both in vitro and in vivo. Activity of HPTL against human brain has not been documented. We have developed an in vitro assay system using particulate membrane fractions which permits comparison of inhibition and recovery kinetics of human RBC (primarily globular dimer) and brain (primarily globular tetramer) membrane-bound forms. Under these conditions the HPTLIC50 is similar for the two forms. RBC AChE inhibition spontaneously reverses in 24 h, as occurs in vivo. In striking contrast, activity of inhibited brain enzyme does not recover on overnight incubation. DDVP-induced inhibition, but not HPTL inhibition, can be reversed by the oxime 2-PAM. Some recovery of HPTL inhibition, but not to the level seen with RBC AChE, occurs on addition of heat-stable fractions from serum or CSF. Brain enzyme recovers rapidly from PHY in this system. Responses of brain and RBC AChE to HPTL indicate that these forms are functionally as well as structurally distinct. Since brain inhibition apparently does not spontaneously reverse like RBC inhibition, peripheral measurements of patient responses should be assessed with caution during treatment with HPTL.

Acetylcholinesterase↗
PubMed1991

Stability of peripheral hematological parameters after chronic acetylcholinesterase inhibition in man.

Acetylcholinesterase (AChE; EC 3.1.1.7) is present in both primitive and mature erythroid cells, and a role has been suggested for the enzyme in regulation of differentiation in the human erythron. AChE is also a major enzyme in the central nervous system; alteration of its activity has been proposed as a therapeutic strategy in Alzheimer disease. We recently treated 18 Alzheimer disease patients with metrifonate, a long-acting AChE inhibitor, over periods up to 7 months, with resulting erythrocyte AChE inhibition as high as 82 per cent of baseline values. Despite chronic reduction of enzyme activity, no significant alterations were noted in erythrocyte, leukocyte or platelet characteristics or numbers that would suggest a deleterious effect of AChE inhibition on normal differentiation. Thus, any modification of developmental pathways appears to be compensated by other regulatory mechanisms in the intact organism.

Alzheimer Disease↗
PubMed1989

Estimation of plasma tacrine concentrations using an in vitro cholinesterase inhibition assay.

THA (9-amino, 1,2,3,4-tetrahydroacridine; tacrine) is currently under study as a cholinesterase (ChE) inhibitor in Alzheimer disease. In this study, a sensitive radiometric assay for THA inhibition of human plasma ChE, suitable for detection of effects of orally administered drug, is described. The assay is sensitive in a range of 4-50 ng/ml plasma. Reversibility of the inhibition permits distinguishing of drug effects on ChE from changes in amount of enzyme synthesized during treatment.

Administration, Oral↗
PubMed1985

Trypanosoma cruzi in the opossum Didelphis marsupialis: an indirect fluorescent antibody test for the diagnosis and follow-up of natural and experimental infections.

The use of an indirect fluorescent antibody test (IFAT) performed in a "sandwich" technique has demonstrated: (i) the usefulness of the test for the diagnosis of Trypanosoma cruzi infection in the opossum Didelphis marsupialis; (ii) the existence of differences in the serological response of the opossum, that were related to the parasite strain and were clearly evident during the follow-up of experimental infections in laboratory born specimens; (iii) that, despite a good correlation between serological and parasitological examinations, IFAT was the most sensitive diagnostic test used, followed by xenodiagnosis; and, (iv) that in general, the opossum D. marsupialis seems to be a good responder to T. cruzi antigens.

Animals↗
PubMed1984

Tissue eosinophilia and Leishmania mexicana mexicana eosinophil interactions in murine cutaneous leishmaniasis.

Outbred albino mice were infected subcutaneously with 10(6) amastigotes of Leishmania mexicana mexicana and the subsequent lesions were evaluated by light and electron microscopy at various intervals after infection. The animals developed persistent nodules and a spectrum of lesions of variable size which was correlated with the host's ability to control the parasite in the tissue. During the acute phase of the disease the histopathological results showed an accumulation of granulocytes, some mononuclear phagocytes and a predominance of eosinophils as compared to other cell types. In this early acute phase, eosinophils were found in the tissue together with normal and degranulating mast cells. In the granulomatous inflammatory reaction of the chronic phases, there was infiltration of granulocytes parallel to parasite multiplication and the formation of parasitized vacuolated macrophages. The number of eosinophils was consistently greater than neutrophils, regardless of lesion type or number of parasites present in the tissue. During the acute reaction, the granulocytes apparently destroyed many parasites; however, there was an unvaryingly low level of phagocytosis of amastigotes during the chronic stages by both eosinophils and neutrophils. Neutrophils seemed to be more effective than eosinophils in the killing of ingested parasites. A close association between eosinophils and parasitized macrophages was seen in the chronic lesions; thus, eosinophils might contribute to parasite destruction through co-operation with macrophages.

Animals↗
PubMed1982

Intralesional plasma cells and serological responses in human cutaneous leishmaniasis.

Intralesional plasma cells and serological responses were investigated in 20 Brazilian cases of cutaneous leishmaniasis. Plasma cell numbers varied from less than 10% to more than 50% of cells in inflammatory infiltrates, in general with greater numbers of such cells present in lesions of longer duration. Direct fluorescence examination with anti-IgG, -IgA and -IgM sera of trypsin-treated sections of formalin-fixed biopsy tissue revealed that most intralesional plasma cells contained IgG. Russell bodies were detected in eight cases, in seven of which these bodies fluoresced only with anti-IgM serum. There was no correlation between serum levels of total IgG, IgA and IgM (detected by radial immunodiffusion) or antileishmanial antibodies (detected by class-specific indirect immunofluorescence and by direct agglutination with and without 2-mercaptoethanol) and numbers of intralesional plasma cells of the same globulin class. No striking or consistent alterations in complement components were noted in the serum of these patients.

Cell Count↗
PubMed1981

A convenient multipurpose mouse restrainer.

A convenient, inexpensive, easily constructed mouse restrainer is described and illustrated. The restrainer has the advantage over other models that while the animal is effectively immobilized, time-consuming and potentially injurious binding of extremities is avoided, and selected areas such as the back, extremities and tail remain accessible for manipulations.

Animals↗