Biomedical subjects

C A George

Publications and source records attributed to C A George.

5 recordsLinked to original sources

PubMed2001

The muscarinic agonist xanomeline increases monoamine release and immediate early gene expression in the rat prefrontal cortex.

BACKGROUND: The muscarinic agonist xanomeline has been shown to reduce antipsychotic-like behaviors in patients with Alzheimer's disease. Because atypical antipsychotic agents increase dopamine release in prefrontal cortex and induce immediate early gene expression in prefrontal cortex and nucleus accumbens, the effect of xanomeline was determined on these indices. METHODS: The effect of xanomeline on extracellular levels of monoamines in brain regions was determined using a microdialysis technique, and changes in expression of the immediate early genes c-fos and zif/268 in brain regions were evaluated using in situ hybridization histochemistry. RESULTS: Xanomeline increased extracellular levels of dopamine in prefrontal cortex and nucleus accumbens but not in striatum. Xanomeline increased expression of c-fos and zif/268 in prefrontal cortex and nucleus accumbens. There was no change in immediate early gene expression in striatum. CONCLUSIONS: Xanomeline increased extracellular levels of dopamine, which is similar to the effects of the atypical antipsychotics clozapine and olanzapine. The regional pattern of immediate early gene expression induced by xanomeline resembled that of atypical antipsychotic agents. Based on the antipsychotic-like activity of xanomeline in Alzheimer's patients and the similarity to atypical antipsychotic agents, we suggest that xanomeline may be a novel antipsychotic agent.

Animals↗

PubMed2000

Substance P regulates PTH secretion through the neurokinin-1 receptor.

The primary regulator of PTH secretion is serum ionized Ca(2+); however, neuropeptide-containing nerve fibers have been localized to the parathyroid gland. The purpose of this study was to determine whether or not substance P (SP) regulates PTH secretion. In dispersed porcine parathyroid cells, SP reversibly inhibited 0.5 mM CaCl(2)-induced PTH secretion (IC(50) = 0.29 nM) and had no effect at CaCl(2) concentrations of 1.5 mM and greater. At 0.5 mM CaCl(2), treatment with a NK-1 selective receptor agonist resulted in a concentration-dependent decrease in PTH secretion (IC(50) = 0.21 nM). In contrast, NK-2 and NK-3 receptor agonists were approximately 100-fold less active than SP or the NK-1 receptor selective agonist. An enantiospecific reversal of the effects of SP on PTH secretion was observed with LY306740, a potent selective NK-1 receptor antagonist (K(i) = 0.125 nM). In porcine parathyroid cells, expression of mRNA for the NK-1 receptor was observed using RT-PCR. In summary, a novel neuroendocrine pathway is described whereby the neuropeptide, SP, regulates PTH secretion through NK-1 receptors.

Acetamides↗

PubMed1997

Mycobacterium smegmatis infection in a healthy woman following a facelift: case report and review of the literature.

In a 35-year-old female HIV-negative patient a facelift was followed by a Pseudomonas aeruginosa wound infection. The infection persisted despite treatment with ciprofloxacin, and an additional bacteriological wound examination revealed Mycobacterium smegmatis as the causative agent. Combination therapy with ciprofloxacin, doxycycline and amikacin led to a slow healing process without the need for further surgical intervention. A relapse 6 months after initial therapy was successfully treated with local measures. Infection with M. smegmatis might have come about by contaminated intraoperative liquids or the application of lipid creams to the open wound. However, microbiological examination of potential sources remained negative. Infection caused by M. smegmatis following plastic surgery should be considered in patients with spontaneous ulceration and violaceous discoloration of the skin adjacent to the surgical wound. Prolonged antibiotic therapy and possibly repeat surgical interventions may become necessary to treat this rare infection.

Adult↗

PubMed1989

[Breast carcinoma: breast-preserving therapy and cosmetic results].

Conservative surgery and radiation therapy for breast cancer is now a well accepted alternative to modified radical mastectomy but the esthetic results are not always satisfactory and often inferior to mastectomy and reconstruction of the breast. The different problems are discussed. A list of selective criteria for limited surgery is established. The author warns against the routine use of conservative surgery and radiation. He gives an overview of the different breast reconstruction techniques.

Adult↗

PubMed1987

Apparent pacemaker malfunction due to ventricular blanking.

Electrocardiographic interpretation in patients with dual chamber pacemakers requires an intimate understanding of their manner of functioning. This report describes a patient whose pacemaker was suspected of malfunction because of failure to sense premature beats. This sense-failure resulted from the fortuitous concurrence of the sensed portion of the premature beat with the ventricular blanking period and was resolved by reducing the low rate limit of the pacemaker. Three principles must be recognized in interpreting suspected failure of sensing: 1. The channel of origin of the pacing artifact must be identified. 2. The surface QRS morphology does not necessarily correspond to the signal detected by the pacemaker. 3. Failure to sense does not necessarily equal pacemaker malfunction.

Cardiac Complexes, Premature↗